University School of Physical education in Wrocław University

Transcription

HUMAN MOVEMENT
University School of Physical education in Wrocław
University School of Physical education in Poznań
f o r m e r ly
C z l ow i ek i R u c h ( Hu m a n M o v e m e n t )
vol. 6, number 2, 2005
81
Akademia Wychowania Fizycznego we Wrocławiu (University School of Physical Education in Wrocław)
Akademia Wychowania Fizycznego im. Eugeniusza Piaseckiego w Poznaniu (University School of Physical Education in Poznań)
Human Movement
formerly człowiek i ruch (human movement)
vol. 6, number 2, 2005, pp. 81–156
Editor-in-Chief Artur Jaskólski
University School of Physical Education, Wrocław, Poland
Associate Editor Wiesław Osiński
University School of Physical Education, Poznań, Poland
Consultant Editor James S. Skinner
Indiana University, Bloomington, Indiana, USA
Editorial Board
Tadeusz Bober
Jan Celichowski Łucja Pilaczyńska-Szcześniak
Marek Woźniewski University School of Physical Education, Wrocław, Poland
Advisory Board
Oded Bar-Or Janusz Błaszczyk
Wojtek Chodzko-Zajko
Charles Corbin Gudrun Doll-Tepper Józef Drabik
Kenneth Hardman
Andrew Hills
Slobodan Jaric Anna Jaskólska
Toivo Jurimae
Han Kemper Wojciech Lipoński
Robert Malina Melinda Manore Philip E. Martin Joachim Mester Toshio Moritani
John S. Raglin Roland Renson
Tadeusz Rychlewski
James F. Sallis Jerry Thomas Peter Weinberg
Guang Yue Wladimir M. Zatsiorsky Jerzy Żołądź
McMaster University, Hamilton, Ontario, Canada
University School of Physical Education, Katowice, Poland
University of Illinois, Urbana, Illinois, USA
Arizona State University, East Mesa, Arizona, USA
Frei University, Berlin, Germany
University School of Physical Education and Sport, Gdańsk, Poland
Manchester University, Manchester, United Kingdom
Queensland University of Technology, Queensland, Australia
University of Delaware, Newark, Delaware, USA
University of Tartu, Tartu, Estonia
Vrije University, Amsterdam, Netherlands
Tarleton State University, Stephenville, Texas, USA
Oregon State University, Corvallis, Oregon, USA
Pennsylvania State University, State College, Pennsylvania, USA
German Sport University, Cologne, Germany
Kyoto University, Kyoto, Japan
Indiana University, Bloomington, Indiana, USA
Catholic University, Leuven, Belgium
San Diego State University, San Diego, California, USA
Iowa State University, Ames, Iowa, USA
Hamburg University, Hamburg, Germany
Cleveland Clinic Foundation, Cleveland, Ohio, USA
Pennsylvania State University, State College, Pennsylvania, USA
University School of Physical Education, Kraków, Poland
Translation: Tomasz Skirecki
Design: Agnieszka Nyklasz
Copy editor: Beata Irzykowska
Proofreading: Halina Marciniak
Indexed in: SPORTDiscus, Index Copernicus, Altis, Sponet
Financial Support: Komitet Badań Naukowych
© Copyright 2005 by Wydawnictwo AWF we Wrocławiu
ISSN 1732-3991
http://www.awf.wroc.pl/hum_mov
Editorial office
Secretary: Bogusława Idzik
51-617 Wrocław, ul. Banacha 11, Poland, tel. (071) 347 31 32, 347 31 73
hum_mov@awf.wroc.pl
Print: Agencja Reklamowa i Drukarnia KONTRA
HUMAN
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HUMAN
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2005, vol. 6 (2)
contents
Editorial....................................................................................................................................................................... 84
Ewa Dybińska
Visual information communication in creation of mental programmes
during teaching motor activities .............................................................................................................................. 85
Witold Ziara
Relationships between progress in acquisition of swimming skills
and anxiety level in ten-year-old children ............................................................................................................... 93
Łucja Pilaczyńska-Szcześniak, Janusz Maciaszek, Ewa Deskur-Śmielecka,
Alicja Nowak, Joanna Karolkiewicz, Tadeusz Rychlewski, Wiesław Osiński
The effect of Tai-Chi training on surrogate index of insulin resistance (homair)
in elderly subjects ...................................................................................................................................................... 98
Daniel P. Potaczek
The issue of gene doping ......................................................................................................................................... 104
Jürgen Klauck
Push-off forces vs kinematics in swimming turns:
Model based estimates of time-dependent variables ............................................................................................ 112
Przemysław Prokopow, Stefan Szyniszewski, Krzysztof Pomorski
The effects of changes in the timing of muscle activation on jump height:
A simulation study ................................................................................................................................................. 116
Teresa Zwierko, Piotr Lesiakowski, Beata Florkiewicz
Selected aspects of motor coordination in young basketball players ................................................................ 124
Zbigniew Borysiuk
Analysis of changes in saber fencing after the introduction of electrical scoring apparatus .......................... 129
Katarzyna Kisiel-Sajewicz, Artur Jaskólski, Anna Jaskólska
Current knowledge in studies on relaxation from voluntary contraction ........................................................ 136
Regulamin publikowania prac/Instructions for Authors........................................................................................... 149
83
HUMAN
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HUMAN
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2005, vol. 6 (2)
EDITORial
We are proud to present our readers with the second
2005 volume of Human Movement. It includes original
articles from a broad range of sports sciences, encompassing sports methodology and education, exercise biochemistry, physiology, biomechanics and training theory.
The present volume contains two articles on the didactic process in swimming. In one of them the problem
of visual information in teaching swimming is discussed.
The authors stress the importance of creation of the mental
picture of an algorithm of a complex motor activity in the
didactic process. The other article on swimming discusses
the link between the process of acquisition of swimming
skills and the level of anxiety. The author of the article
carefully concludes that systematic exercise does not
necessarily reduce the anxiety level in children. Another
article examines the contemporary problem of obesity.
The authors show that a tai-chi-based four-month training
can be an effective, non-pharmacological measure that
prevents certain metabolic disorders. We also would like
to draw attention of all our readers interested in biome
chanics to a collective simulation study on the effects of
timing of muscle activation on jump height. Another
article on biomechanics is concerned with the model of
forces during swimming turns. Finally, a paper on bas
ketball focuses on the timely problem of players’ selection, i.e. the role of motor coordination as one of selection
criteria. We have also decided to include two review
studies: one on muscle physiology, i.e. muscle relaxation
during voluntary contraction, and the other on gene doping, an important current issue in the area of sports
medicine. Our journal is currently indexed in the SPORT
Discus, Sponet, Altis and Index Copernicus databases.
In 2004 we received 5 points from the Polish State Com
mittee for Scientific Research.
As of September 1, 2005, I was recalled from the
post of Editor-in-Chief of Human Movement by the President of the University School of Physical Education
in Wroclaw. I would like to inform you that the new
Editor-in-Chief of Human Movement will appoint his
own Advisory Board, and I am writing to thank you very
much for your contribution to the journal so far. My
cooperation with the Associate Editor, Consultant Editor
and Advisory Board has been crucial in accomplishment
of our mission. I should be especially grateful to the
reviewers for their critical evaluation, as thanks to them
our journal remains at a high scientific level. My special
thanks go to reviewers of both 2005 volumes:
84
Brian Blanksby, Perth (Australia)
Tadeusz Bober, Wrocław (Poland)
Maarten Bobbert, Amsterdam (The Netherlands)
Jan Celichowski, Poznań (Poland)
Jean-Claude Chatard, Saint-Etienne (France)
Joachim Cieślik, Poznań (Poland)
Ewa Demczuk-Włodarczyk, Wrocław (Poland)
Dariusz Doliński, Wrocław (Poland)
Tadeusz Dobosz, Wrocław (Poland)
Józef Drabik, Gdańsk (Poland)
Piotr E. Dylewicz, Poznań (Poland)
Jeffrey T. Fairbrother, Knoxville (USA)
Grażyna Lutosławska, Warszawa (Poland)
Stanisław Gołąb, Kraków (Poland)
Henryk Grabowski, Kraków (Poland)
Jacek Gracz, Poznań (Poland)
Andrew Hills, Queensland (Australia)
Zofia Ignasiak, Wrocław (Poland)
Lidia Ilnicka, Warszawa (Poland)
Slobodan Jaric, Newark (USA)
Anna Jaskólska, Wrocław (Poland)
Jerzy Jaśkiewicz, Kraków (Poland)
Grzegorz Juras, Katowice (Poland)
Toivo Jurimae, Tartu (Estonia)
Maria Kaczmarek, Poznań (Poland)
Roman M. Kalina, Warszawa (Poland)
Barbara Kłapcińska, Katowice (Poland)
Kazimierz Kochanowicz, Gdańsk (Poland)
Kathy Koltyn, Madison (USA)
Stanisław Kowalik, Poznań (Poland)
Robert M. Malina, Bay City (USA)
Joachim Mester, Köln (Germany)
Janusz Nowotny, Katowice (Poland)
Claudio Orizio, Brescia (Italy)
Wiesław Osiński, Poznań (Poland)
Derek M. Peters, Worcester (UK)
Paul Poirier, Quebec (Canada)
Joachim Raczek, Katowice (Poland)
Elżbieta Rostkowska, Poznań (Poland)
Tadeusz Rychlewski, Poznań (Poland)
Igor Ryguła, Katowice (Poland)
Ann L. Smiley-Oyen, Ames (USA)
Tadeusz Sankowski, Poznań (Poland)
Włodzimierz Z. Starosta, Gorzów Wlkp. (Poland)
Maria Straś-Romanowska, Wrocław (Poland)
Ryszard Strzelczyk, Poznań (Poland)
Andrzej Szmajke, Wrocław (Poland)
Czesław Urbanik, Warszawa (Poland)
Dominic J. Wells, London (UK)
Andrzej Wit, Warszawa (Poland)
Barbara Woynarowska, Warszawa (Poland)
Marek Woźniewski, Wrocław (Poland)
Jerzy Zagórski, Lublin (Poland)
Marek Zatoń, Wrocław (Poland)
Janusz Zdebski, Kraków (Poland)
Jerzy Żołądź, Kraków (Poland)
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2005, vol. 6 (2), 85–92
VISUAL INFORMATION COMMUNICATION IN CREATION
OF MENTAL PROGRAMMES DURING TEACHING MOTOR ACTIVITIES
Ewa Dybińska
Departament of Sport Theory and Methods, Academy of Physical Education in Kraków, Poland
Abstract
Purpose. This paper is an attempt at defining the significance of the content of visual information to successful acquisition of complex
motor actions by children at a younger school age. The research assumptions were formulated as follows: the techniques for visual
information communication that are adequately prepared and adapted to the perceptive capacity of pupils may be helpful in the
creation of a mental plan of activities for the motor algorithm of the activity taught. Basic procedures. A method of natural pedagogical
experiment was used in this research. The research was conducted among third-form pupils from selected primary schools who
attended their obligatory swimming lessons. The final analysis involved 532 children, 279 from the experimental group and 253 from
the control one. The experimental factor – independent variable – was the manner of developing visual information about the movement technique being taught, whereas the dependent variables consisted of the teaching results concerning: mastering of the crawl by
the pupils as well as formation of motor visualizations about the motor activity being taught. Main findings. The differences between
the variables under study were calculated by means of t-Student test. In order to provide an answer to the research questions, relationships between the analysed variables were searched for by means of variance analysis as well as Pearson’s coefficients of linear
correlation. Conclusions. The results of the analysis enabled us, among others, to draw some conclusions that creation of a mental
picture of an algorithm of a complex motor activity during all stages of schooling was crucial to the effectiveness with which this skill
was acquired.
Key words: learning and teaching swimming, visual information, motor visualizations
Introduction
When learning and teaching swimming activities the
manner, kind and selection of information communicated
during lesson plays a special role for the effectiveness
of this didactic process. The information communicated
to the pupil in the course of teaching specific motor
activities should make it easy for him/her to solve his/
her task, which is its execution. The aquatic environment
through its different physical properties (in comparison
with air) poses huge barriers to learners, thus impairing
their correct reception of information, especially of visual and verbal nature. During exercises in water, pupils
receive hundreds of thousands of stimuli and sensations,
to which they react with different intensity, which provokes in them (through kinesthetic receptors) specific, and
often undesirable reactions and brings about disturbances
to their didactic perception. When creating motor visuali
zations about the movement technique being taught, the
verbal and visual information delivered on the shore is
indispensable, but it is only an indirect link in the mas
tering of swimming activities. Kinesthetic information
is indispensable for full and correct motor visualizations.
The most important information necessary for mastering
movement technique is acquired by the pupil in water,
and practically all receptors, particularly kinesthetic
ones, are involved in its perception. This information
concerns, among others, disturbances of balance and
changes in the position of the body in water (perceived
by the labyrinth), pressure of water resistance on the
paddling surfaces of extremities, feeling of water resistance all over the body (via receptors of the skin), reaction of muscular forces (via receptors in tendons),
angular changes during movements of extremities (via
receptors in joints), water pressure, body buoyancy and
its weight (via interoreceptors) [1].
In connection with the above, pieces of verbal and visual
information play only complementary and supporting part
during learning and teaching process of swimming activities. However, properly prepared and inculcated information, especially visual one, which affecting optic
receptors helps to create accurate, precise and conscious
image of motor activity, can considerably contribute to
enhancement of the effectiveness of this didactic process.
The importance of visual information transfer for the
efficiency of learning and teaching motor activities has
been discussed by many authors as far as different aspects
are concerned. Frömel [2] and Nowak [3] proved the
teaching efficiency of motor activities using programmed
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E. Dybińska, Visualizations in the teaching of motor activities
charts, especially among people with different motor
abilities. Moreover, Nowak [3] stated in his research that
the charts are programmed not only with a helpful form
of information transfer but also they make a crucial factor
which powers the idea of pupil’s independence and self-control. Also, experimental research by Czabański [4]
indicated clear relationships between the image, the
mental ‘picture’ of an activity and their practical implemen
tation thanks to, among others, the use of a programmed
chart in the didactic process. However, during those
observations, it was not fully explained whether it was
motor images or practical activities that had a greater
share in mental programming of a motor activity.
Through her empirical research, Guła-Kubiszewska
[5] proved the significance of an internal programming
film in motor image creation, especially the one that
influences the image of individual phases of an activity.
The author showed in her observations that motor images
are the factor which controls motor activity by writing
that “the higher the level of motor image, the higher the
level of motor activity implementation” [5, p. 43].
On the other hand, Wiesner [6] while investigating vi
sual information efficiency in teaching motor activities,
made a series of observations concerning the use of
a didactic film. He stated that “thanks to the use of a didactic film there is a potential chance of increasing the
teaching efficiency even by 20%” [6, p. 82]. The problem
of visualization, i.e. repeating from memory the picture
that has been remembered (thanks to visual receptors)
was also undertaken by Botwina and Starosta [7], but
mainly in the case of sport training process efficiency for
different sport disciplines (football, handball, wrestling).
These authors were of the opinion that the use of visuali
zation in the training process means “setting the ideomotor
force which is inside each of us into move” [7, p. 74], so
this is the technique powering the accomplishment of
a sport result.
Problem, hypothesis, research questions
Taking into consideration the results of research on
the importance of visual information transfer in teaching
motor activities, an attempt at observing this problem in
younger schoolchildren has been made. With these
children, at this stage of their psychomotor development,
visual-motor thinking plays a major role in thinking processes [8].
The main goal of the research work was an attempt
to specify the significance of visual information transfer
to the efficiency of mastering complex motor activities
86
by the example of learning and teaching swimming acti
vities to 10-year-old children.
The following research questions mark the way to
accomplish this goal:
1. To what extent does the use of adequate visual in
formation transfer techniques influence the creation
of a mental plan and the algorithm program of
a motor activity?
2. To what extent, at successive learning and teaching
stages, does visual information influence the
precision of a motor task accomplishment?
Hence, the following research theses have been formulated:
1. The efficiency of learning and teaching motor
activities increases thanks to such a visual informa
tion transfer which enables us to create (set up)
a mental program of a motor activity.
2. Visual information transfer techniques that are
adequately prepared and adjusted to the perception
abilities of 10-year-old pupils help in the creation
of a mental plan of the motor algorithm of the
activity being taught and, as a result, help in developing the efficiency of accomplishing his/her
activity during further learning and teaching steps.
Method and material
This research was conducted among third-form pupils
from selected primary schools, who attended their obligatory swimming lessons in the second semester during
the school year 2001/2002. They took lessons once a week
at the swimming pool of Krakowski Szkolny Ośrodek
Sportowy – KSOS (Cracovian School Sports Centre).
The children were taught complex motor activity which
was the crawl swimming technique at a standard level
according to the programme developed by future KSOS
teachers.
The method of natural pedagogical experiment was
employed in order to determine the significance of the
content of visual information during the formation of
a plan – mental programme – of the motor activity being
taught. The technique of parallel groups was implemented: experimental (E) and control one (C). The experiment
involved 597 children, who were divided using random
numbers into two groups of 298 and 299 pupils. Taking
into account the children’s absences from lessons (their
attendance above 75%) and discarding their incomplete
tests, the final analysis involved 532 children, 279 (147
girls and 132 boys) from the experimental group and
253 (122 girls and 131 boys) from the control one.
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Assumptions of the experiment
The selected groups were homogeneous in terms of
their swimming prowess level because they were subjected to a placement test according to the following
criteria: 1. lack of aquaphobia – evaluated by means of
the Criterion-related Anxiety Test [1], 2. ability to perform
feet-first jumps into water, 3. ability to execute 3–5
combined exhalations into water, 4. ability to glide on
the chest for a distance of 5 m, 5. ability to cover a distance of 20–25 m using the backstroke or by swimming
on their back with alternating movements of legs, 6. no
ability to use the crawl.
The swimming syllabus was implemented in group E
and C in the course of 14 lessons lasting 40 min each.
The swimming skills trained in both groups were based
on the same assumptions contained in the syllabus and
were accomplished by means of the same methods, forms
and teaching aids.
Teaching conditions were identical in both groups
during the experiment. Groups (E and C) were equalized
as far as the conditions which could influence the speed
of developing swimming abilities were concerned. The
conditions include: intelligence level – checked with
Raven test [9], fear level and the level of selected motor
abilities (fitness and coordination).
The experimental factor – independent variable – was
the manner of developing visual information about the
movement technique being taught, whereas the deendent
variables consisted of the teaching results concerning:
mastering of the crawl by the pupils as well as formation
of motor visualizations about the motor activity being
taught.
Traditional means of communicating visual infor
mation were applied in control group (C) by way of
demonstrating movement technique during the teaching
of swimming activities. However, the communication
of visual information used in lessons during the experiment (group E) consisted in inculcating the additionally
developed didactic aids that acted mostly on optical
receptors in the form of programmed cards, prepared on
the basis of Czabański’s programmed card [4] and programmed film [1].
The programmed cards as well as the programmed
film were developed in keeping with the present-day,
cognitive concept of many-sided education which applies to the teaching and learning by changing the three
types of behaviour in pupils, namely cognitive (thinking,
reasoning, knowledge), emotional (attitudes, convictions,
values) and psychomotor (motor activities, abilities, skills)
[10, 11]. The programmed card applied during the experiment consisted of 6 pictures containing 6 stages (steps)
[1] of algorithm sequence of one movement cycle of the
crawl. When designing the cards, the crawl swimming
technique was simplified to these (six) elements of activity, namely “crucial sequences”, which are “basic points
of support” of this movement technique and during the
analysis of motor algorithm they ought to be noticed and
consciously committed (programmed) to memory.
Thanks to the possibility to slow down and/or stop
pictures or repeat them many times, the programmed
film applied during the experiment made it possible to
show the elements of motor activities, which often one
does not notice during a natural demonstration. It was
meant to fulfil both the motivating and also instructing
function during the didactic process.
The film showed the order of motor sequences of the
crawl at a standard level according to the motor algorithm
contained in the programmed cards. “The crucial motor
sequences” were presented at a slow speed, which had
to serve the individual abilities of each pupil to notice
and remember.
The pictures (silhouettes) on the programmed cards
and also the programmed film were adapted in graphic,
visual and also verbal terms to the perception abilities
of 10-year-old children.
In the experimental group, the manner of the instruction of the crawl at a standard level with regard to the
additional communication techniques of visual information, that served to mental program development of
motor activity being taught in every lesson, consisted in
performing the following activities by the children: 1.
watching the programmed film for 5 min before the start
of lesson, 2. watching the programmed cards before
their entry to water – and analyzing consecutive sequences of motor algorithm for the crawl, 3. individual
arrangement of the consecutive sequences of the motor
algorithm (6 drawings) by pupils (from memory).
To evaluate the level the children had mastered their swimming skills, a swimming prowess test was conducted which consisted in swimming a distance of 20–25
m using the crawl at a standard level and in appraising
their swimming technique by means of 10 pts. of the
established criteria. Detailed assumptions and criteria
for evaluation of the swimming test have been described
elsewhere [12].
The results of the swimming test were expressed in
penalty points: the fewer points the subject scored the
better result he/she obtained.
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Statistical analysis
The material collected during the empirical research
was subjected to a statistical analysis by performing basic
calculations on statistical parameters of the arithmetic
mean and standard deviation. The differences between
the variables under study were calculated by means of
t-Student test. In order to provide an answer to the research questions, relationships between analysed variables
were searched for by means of variance analysis as well
as Pearson’s coefficients of linear correlation [13].
Results
At the beginning of the study, tests for motor abilities
as well as IQ tests were conducted (by means of Raven’s
test) for the purpose of determining possible differences
between both groups, which might have potential significance for the speed with which the subjects acquired
new motor skills. The calculations accomplished by means
of t-Student test permitted us to discover that no statistically significant differences appeared in the variables
taken into account. This allowed us to assume that both
the experimental and control groups displayed similar
speeds of learning.
We searched for relationships between the analysed
variables in order to answer the fundamental research
question: To what degree does the creation of a mental
plan, programme of motor activity algorithm with the use
of suitable communication techniques of visual information influence the efficiency with which this activity
is mastered during the consecutive stages of learning?
88
Table 1. Comparison of both groups in terms of analysed
variables (mean results of motor image – x
and swimming ability test – S [points])
x
x
S
S
E
C
E
C
t
df
p
M.V.L.4
0.907 0.312 0.799 0.497
10.18 530 < 0.001
M.V.L.7
1.713 0.636 1.075 0.720
13.44 530 < 0.001
M.V.L.10 2.358 0.968 1.191 0.865
15.25 529 < 0.001
M.V.L.14 3.050 1.348 1.343 1.112
15.84 530 < 0.001
S.P.L.4
8.676 9.332 1.238 1.099
–6.43 529 < 0.001
S.P.L.7
7.247 8.470 2.137 1.967
–6.85 530 < 0.001
S.P.L.10
5.871 7.925 2.214 2.242 –10.60 528 < 0.001
S.P.L.14
4.133 7.111 2.705 2.833 –12.40 530 < 0.001
E – experimental group, C – control group
M.V. – motor visualization, S.P. – swimming prowess, L – lesson
3,5
group E
3
motor visualization
The test that served to determine the level of motor
visualizations concerning the crawl swimming technique
at a standard level consisted in individual arrangement
by the pupils during the prescribed time (less than 5 min)
of 8 drawings constituting one movement cycle – 6
according to the algorithm contained in a programmed
card and the programmed film – as well as in showing
2 wrong pictures (not belonging to the sequence of
motor algorithm for the crawl). When calculating the test
results concerning the level of motor visualizations, the
coefficients proposed by Czabański [4] were taken into
account during the analyses. The motor visualizations
index was expressed in points: the more points the subject scored the better result he/she obtained.
The above tests took place at the following times: first
test – lesson 4 – beginning of learning, second test – le
sson 7 – middle of schooling, third test – lesson 10 – the
end of instruction, fourth test – lesson 14 – end of the
lessons.
group C
2,5
2
1,5
1
0,5
0
lesson 4
lesson 7
lesson 10
lesson 14
Figure 1. Increase in motor visualizations during the consecutive tests in the experimental and control groups
The changes in the level of motor visualizations as
well as swimming prowess during the analysed, consecutive trials have been presented in tables and graphs.
When analyzing the results in Table 1, which concern
the differences between the mean results of the motor
images and swimming ability test (examined with t-Student test) one can see that the experimental group achieved
significantly better results (p < 0.01) in terms of both the
motor images level and the swimming ability. These
differences are seen in all four experiments, i.e. at all
teaching levels.
As follows from the data presented in Figure 1, it can be
stated that the dynamics of the increase in motor visua
lizations was distinctly higher in group E than in group
C, in the case of which considerably smaller increases
in motor visualizations about the movement technique
being taught were observed between consecutive tests.
Furthermore, the motor visualizations index showed
the least diversification (Fig. 1) between the experimental and control groups during the first test, which was at
HUMAN MOVEMENT
the beginning of the swimming lessons (during lesson 4).
However, in the consecutive trials (second, third one)
those differences were greater and greater, while during
the last test (fourth one at the end of the lessons) the
greatest differentiation ( p < 0.001) was observed.
One can also point out that this increase in visualizations in both groups was very even, without visible
“abrupt changes” or stages of stagnation.
For the evaluation of motor images growth in experi
mental and control groups analysis of variance ANOVA
(Tab. 2) was used.
This increase in motor visualizations (Tab. 2) (regard
less of the group) was statistically significant (marked by
a line in the table called MOMENT), yet in the experimental group the effect of faster (more “abrupt”) increase
in motor visualizations was stronger than in the control
group ( p < 0.001) (in the table, this line of analysis is
marked by MOMENT*Group).
One can note that both groups improved their results
during following trials (obtaining smaller number of
penalty points) for their swimming prowess (Fig. 2) and
also for motor visualizations, yet this improvement was
clearly greater in the experimental than control group.
Swimming prowess displayed least differentiation
(Fig. 2) between the experimental and control groups
and during the first test, which meant the beginning of
swimming lessons (during lesson 4). However, during
the consecutive trials (second and third one) those diffe
Table 2. Analysis of variance (ANOVA) of motor image
growth in the whole group and in groups E and C
p
MOMENT (whole group)
984.29
< 0.001
MOMENT*Group
(groups E and C)
120.13
< 0.001
swimming prowess
F (3,1587)
10
9
8
7
6
5
4
group E
group C
3
2
1
0
Table 3. Analysis of variance (ANOVA) of swimming ability growth in the whole group and in groups E and C
F (3,1584)
p
MOMENT (whole group)
1305.50
< 0.001
MOMENT*Group
(groups E and C)
162.90
< 0.001
rences were more and more sizable, while the greatest
differentiation was observed ( p < 0.001) during the final
test (fourth one at the end of the lessons).
Analogously to motor visualizations, the increase in
fitness in both groups was very even, without abrupt
changes and phases of stagnation.
For the evaluation of swimming ability growth in
experimental and control groups analysis of variance
ANOVA (Tab. 3) was used.
The increase in swimming prowess (Tab. 3) (regard
less of the group) was statistically significant (line in
table MOMENT), however the effect of quicker (more
“rapid”) acquisition of swimming skills was stronger in
the experimental group than in the control one ( p < 0.001)
(in the table, this line of analysis is marked by MOMENT*Group).
In order to determine the dependence between the
level of motor image and swimming ability between the
experimental and control groups during successive tea
ching steps, Pearson’s linear correlation was used to
calculate correlation coefficients (Tab. 4).
In Table 4, correlations for the experimental group
are placed over the diagonal, while those for the control
group are under the diagonal. The correlations of both
variables of matching measuring points (consecutive
tests) are marked for both groups in bold type.
The results for the values of Pearson’s linear correlation (Tab. 4) proved statistically significant ( p < 0.01)
in all cases analysed. Therefore, one may ascertain that
the increase in swimming prowess during the consecutive
tests (first, second, third and fourth one) was closely
connected with the growth concerning visualizations of
the algorithm of motor sequences of the activity taught
to both the experimental and control groups.
Discussion
lesson 4
lesson 7
lesson 10
lesson 14
Figure 2. Increase in swimming prowess during the consecutive tests in the experimental and control groups
According to many authors [14–19] one of the significant factors that condition the effectiveness during the
process of learning and teaching motor activities is
89
HUMAN MOVEMENT
Table 4. Values of Pearson’s correlation coefficients between swimming prowess and motor visualizations
during the consecutive trials – experimental and control groups
M.V.L.4
M.V.L.7
M.V.L.0
M.V.L.4
S.P. L.4
S.P. L.7
S.P.L.10
S.P.L.14
M.V.L.4
0.80
0.75
0.74
–0.68
–0.58
–0.59
–0.58
M.V.L.7
0.67
0.88
0.84
–0.72
–0.69
–0.69
–0.68
M.V.L.10
0.67
0.79
0.88
–0.68
–0.66
–0.67
–0.66
M.V.L.14
0.59
0.77
0.85
–0.71
–0.70
–0.71
–0.73
S.P. L.4
–0.60
–0.72
–0.74
–0.77
0.83
0.81
0.79
S.P. L.7
–0.54
–0.67
–0.72
–0.77
0.90
0.92
0.93
S.P.L.10
–0.56
–0.68
–0.73
–0.79
0.88
0.95
0.94
S.P.L.14
–0.54
–0.69
–0.73
–0.80
0.85
0.95
0.96
M.V. – motor visualizations, S.P. – swimming prowess, L – lesson
All correlations are statistically significant at p < 0.01.
a manner of effective and optimum didactic communication concerning the mode of communicating and receiving
information between the teacher and the pupil. The
information obtained by the learner is compared with
the specific stock of his or her motor memory and it generates a picture (visualization) of motor activity in the
mind of the learner. The more diversified information
concerning the activity being taught is received by the
pupil the more thoroughly and accurately it will be stored in his or her consciousness, which in turn will help
him or her to form a mental programme in order to anticipate activities. Thanks to formation of the mental
plan and programme of this activity, the pupil can arrange
and control the order according to which the assumed
sequence of movements should take place (order of
motor sequences) [17, 20–22]. Therefore, during teaching it is essential to understand the progression of
the entire activity, its structure, the manner in which the
whole of it is composed, its consecutive elements as well
as the interrelation between them, which consequently
supports mental planning and programming as well as
further effective performance of this activity.
One of the basic information transfer means in creating
motor image is (as mentioned before) the information
transfer which affects visual receptors and takes into
consideration different transfer forms. According to Cava
llier visualization “is the activating process of perception
and emotional experience which aims at using collected
psychical resources for future plans and their implemen
tation. Visualization works similarly to the screening of
a film from the past in order to forecast the future. Of
course, this screening influences not only our hopes for
90
the future, but also our activity and implementation of our
plans and intentions” [23, p. 62].
The results of the tests do not fully explain the problem of the meaning of visual information transfer in
creating the mental program of the motor activity taught.
For example, in the case of younger schoolchildren,
several processes are not completely known. They include movement control mechanism during the learning
process, precise mental programming in learning complex motor activities, or specifying at which learning
stage the strategy of solving a motor task corresponds to
correct images of the task.
Bearing in mind the remarks presented above, properly prepared and initiated communication techniques
of visual information during the learning and teaching
of swimming activities to children at younger school age
proved to have a significant influence on the results
obtained during the experiment. The execution of the
motor visualizations test consisting in arranging the
correct order of 6 drawings of motor algorithm of the
activity taught revealed that the vast majority of children
from the experimental group indicated the order of motor sequences of the activity taught more accurately, so
they better remembered the pictures depicted in the
programmed cards and programmed film.
During the consecutive stages of learning and teaching
in swimming activities, one could observe a clearly visible
dynamics in the improvement of motor visualizations
about the movement technique being taught in the experimental group in comparison with the control one. In
the course of each test (first, second, third and the fourth
one) differences between the groups were statistically
HUMAN MOVEMENT
significant ( p < 0.001), wherein the pupils from group
E attained the highest level of visualizations about the
order of crawl motor sequences at the end of swimming
lessons. Therefore, one can conclude that the level concerning visualizations of the algorithm sequence of motor
activity taught gradually increased in the experimental
group during the following stages of learning. However,
between the consecutive tests a considerably smaller
increase in motor visualizations about the movement
technique being taught was observed in the control
group. This was also connected with a noticeable increase in swimming prowess.
This acquisition of the adequate level of swimming
prowess was closely related with the increase in motor
visualizations. The level of mastering the free style
gradually rose together with the number of the attended
lessons in the studied groups, while during the consecutive (four) trials the pupils from group E attained a
considerably higher ( p < 0.001) level of acquired skills
than those from group C. The dynamics of this increase
was approximate to the rise in the level of motor visualizations of the motor algorithm of the swimming
technique taught.
The presented research proved the traditional demonstration methods [24, 25] applied during the lessons to
be little effective during the formation of motor visualizations both from the point of view of the teaching goal
(creation of correct, conscious, and full image of motor
activity) and in visualizing the way leading to accomplish
ment of this aim, at least by no possibility to slow down
movements, i.e. prolonging the time to remember the
same number of information (which is possible, e.g.
during the programmed film), or making allowances for
pupils’ individual, perceptive capacities during the reception of this information. Therefore, these methods
do not meet the qualitative requirements that are necessary for pupils to receive visual information.
Conclusions
Recapitulating the issues considered one can formulate the following sweeping statements:
1. At all teaching stages (lessons 4, 7, 10 and 14) the
experimental group achieved better results of the
level of motor images and swimming ability.
2. The growth of motor images and swimming ability in successive lessons was statistically important but it was higher in the experimental group
than in the control one.
3. Creating a mental picture of the complex motor
activity algorithm at all teaching stages showed,
according to the correlation coefficient, a significant connection with the efficiency of its mastering by younger schoolchildren. The better the
pupils imagined the motor activity, the easier they
learned swimming abilities.
4. The use of adequate information transfer techniques by affecting visual receptors proved efficient
both in creating a mental program of the motor
activity taught and in achieving an adequate level
of swimming ability.
References
1. Dybińska E., Optimization of visual information as the factor
facilitating learning and teaching swimming activities of 10-year-old children [in Polish]. Studia i Monografie AWF w Krakowie,
2004, 25.
2.Frömel K., Didactic aspects of programmed teaching in physical
education [in Polish]. Zeszyty Naukowe AWF we Wrocławiu,
1989, 50, 13–20.
3.Nowak A., The efficiency of programmed charts in teaching sport
activities [in Polish]. In: Czabański B. (ed.), Learning a sport
technique. AWF, Wrocław, 1991, 41–55.
4.Czabański B., Motor images vs motor abilities. Learning sports
technique [in Polish]. AWF, Warszawa 1991.
5. Guła-Kubiszewska H., Programming function of motor image
as a factor forming the strategy of solving complex motor tasks
[in Polish]. Wychowanie Fizyczne i Sport, 1996, 1, 20–45.
6.Wiesner W., Didactic film in motor activities teaching process
[in Polish]. In: Czabański B. (ed.), Learning a sport technique.
Warszawa 1991, 56–95.
7.Botwina R., Starosta W., Mental Powering of Sportsmen. Theory
and Practice. [in Polish]. International Association of Sport
Kinetics, Warszawa–Gorzów Wlkp. 2002.
8.Włodarski Z., Matczak A., Introduction to psychology [in Polish].
WSiP, Warszawa 1992.
9.Jaworowska A., Szustrowa T., Raven matrix test – a handbook.
Standard version (1956) [in Polish]. Polska standaryzacja 1989
(5;11–15;11). Pracownia Testów Psychologicznych TPT, Warszawa 1991.
10.Okoń W., Introduction to general didactics [in Polish]. PWN,
Warszawa 1987.
11. Czabański B., Direct, offering and searching teaching in mas
tering swimming ability [in Polish]. Człowiek i Ruch, 2003, 2(8),
41–44.
12.Dybińska E., Evaluation of learning and teaching efficiency of
swimming activities with young children in relation to selected
motor abilities. In: Bartoszewicz R., Koszczyc T., Nowak A.
(eds.), Control and evaluation system in physical training [in
Polish]. AWF, Wrocław 2003, 321–330.
13.Ferguson G.A., Takane Y., Statistical analysis in psychology and
pedagogy [in Polish]. PWN, Warszawa 1997.
14.Bogen M.M., How to increase the effectiveness of teaching
motor abilities [in Polish]. Zeszyty Naukowe AWF we Wrocławiu,
1989, 50, 150–154.
15.Czabański B., Teaching sports activities as teacher–learner
communication system [in Polish]. Zeszyty Naukowe AWF we
Wrocławiu, 1982, 29, 27–33.
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16.Czabański B., Didactic communication in physical training
process. In: Physical training didactics – Didactic communication
in physical training [in Polish]. AWF, Wrocław 1996, 14–24.
17.Pöhlmann R., Basic functional elements of sports-motor learning
spiral [in Polish]. Zeszyty Naukowe AWF we Wrocławiu, 1985,
38, 43–56.
18.Singer R.N., Motor behavior and the role of cognitive processes
and learner strategies. In: Stelmach G.E., Requin J. (eds.), Tutorials in motor learning. North-Holland, Amsterdam 1980.
19.Weinberg P., Learning sports activities vs Galperin theory [in
Polish]. Zeszyty Naukowe AWF we Wrocławiu, 1985, 38, 59–39.
20.Hotz A., Learning motor activities as creating, specifying and
implementing an internal model (or an image) of movements [in
21.Zatoń K., Influence of the quality and quantity of verbal informa
tion on creating plans and programmes of a motor activity [in
22.Schmidt R.A., Motor Learning and performance: from principles
to practice. Human Kinetics, Champaign, Illionois 1995.
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23.Cavallier F.P., Visualization. From image to activity [in Polish].
Rebis, Poznań 1996.
24.Czabański B., A model for learning and teaching sports motor
activities [in Polish]. Studia i Monografie AWF we Wrocławiu,
1980, 1.
25.Czabański B., Optimization of learning and teaching sport activities [in Polish]. AWF, Wrocław 1986, 14.
Paper received by the Editors: November 25, 2004.
Paper accepted for publication: May 15, 2005
Address for correspondence
Ewa Dybińska
Akademia Wychowania Fizycznego
ul. Rogozińskiego 12
31-559 Kraków, Poland,
e-mail: ewadyb@wp.pl
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2), 93–97
RELATIONSHIPS BETWEEN PROGRESS IN ACQUISITION OF SWIMMING
SKILLS AND ANXIETY LEVEL IN TEN-YEAR-OLD CHILDREN
Witold Ziara
Department of Sport Theory and Methods, Academy of Physical Education in Kraków, Poland
Abstract
Purpose. The following study attempts to determine changes in the anxiety level in school-age pupils in relation to the swimming learning
progress. Basic procedures. The results of the study were obtained from the population of 69 pupils. For evaluation of basic swimming
skills a set of 10 swimming control exercises on the first instruction level (introductory adaptation) was applied. For evaluation of the level
of state anxiety (S-A) a modified, Polish adaptation of Spielberger’s State-Trait Anxiety Inventory (“Self-evaluation Questionnaire”) was
used. Main findings. The analysis and observations performed confirmed a strong correlation between the level of anxiety (state anxiety)
experienced in the water and swimming skills (especially at the early training stage). It is also important that despite improvement of
swimming skills the average anxiety level decreased very slightly. It seems that the swimming learning progress is based on systematically repeated exercises, which (sooner or later) would bring desired effects. This, in turn, does not have to mean a decreasing anxiety
level. The correlation between a reaction to a particular hazard (state anxiety) and the level of anxiety as a personality trait is also important.
Intensification of anxiety on an almost steady level can determine some “limitary” value, which if crossed can have a disorganizing influence on child’s behavior. Conclusions. Despite the observed progress in swimming skills the average level of anxiety failed to decrease
significantly. The initial anxiety level can have a decisive impact on the subsequent swimming learning stages in children.
Key words: anxiety, swimming, children
Introduction
Anxiety as a psychological phenomenon
Anxiety is probably one of the most deeply rooted
emotions in human psyche. Its existence is as essential
as satisfaction of basic physiological needs. Anxiety
warns the body about dangers, inhibits adverse actions,
or commences rescuing actions [1, 2]. As far as an object
of anxiety is concerned two kinds of anxiety can be
distinguished: anxiety about a particular phenomenon
(physical or imaginary), close to the notion of fear; and
abstract anxiety, close to the notion of apprehension. It
can be assumed that fear is an objective state formed in
the face of a real existing threatening situation; whereas
apprehension is evoked by an internal stimulus, often
by an imaginary threatening situation [3].
The two kinds of anxiety can be related to the dis
tinction between state and trait anxiety. According to
Cattell [4], state anxiety is a temporary emotional arousal
in the face of threatening demands or dangers; whereas
trait anxiety reflects the existence of stable individual
differences in the tendency to respond with state anxiety in the anticipation of threatening situations. This
concept of anxiety has also been discussed and popularized by Spielberger [5].
Anxiety and learning to swim
Nowadays, at the time of growing popularity and
availability of various forms of water recreation, swimming has become a desirable and even necessary skill.
Today, swimming is not merely a survival skill to prevent
drowning, but primarily a sport and a form of relaxation
and rehabilitation [6–8] taken up at a very early age [9,
10]. However, despite this cultural shift the primordial
fear of water has not been eradicated from human nature
[1, 2, 11, 12]. Even good swimmers experience certain
emotions, as swimming, like any psychomotor behavior,
is always accompanied by some emotional tone [13].
This is especially visible during learning swimming [14].
As Gracz and Sankowski claim, emotional arousal strongly stimulates learning motor skills [15].
Swimming classes have been introduced as a core
subject to Polish primary schools and they have greatly
contributed to improvement of swimming skills among
Polish children and adolescents. Unfortunately, an alarming development can also be observed: the number of
school students unwilling to participate in swimming
classes, or sometimes openly avoiding them, has been on
the increase. In many students, contact with water brings
about stress and aversion, and in some cases extreme
fear [16–19]. The causes of this stress might be found in
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W. Ziara, Anxiety and motorskills in swimming
distinct experiences involved in swimming classes as
opposed to other PE activities.
Aim
The problem of learning and teaching swimming skills
in the context of anxiety has inspired the author of the
present paper to carry out a study attempting to determine
changes in the level of anxiety related to swimming
learning among primary school pupils.
Three research questions were posed:
1. How is the anxiety level being developed in the
swimming learners under study?
2. What are the characteristics of the process of
acquisition of basic swimming skills in children?
3. What are the relationships between the level of
swimming skills and the level of anxiety during
swimming classes?
The following research hypothesis was formulated:
The anxiety level (its initial value in particular) in the
water during swimming classes is strongly correlated with
the level of acquisition of swimming skills in 10-year-old
children.
Material and methods
Characteristics of the studied sample
The studied group consisted of 100 children, aged ten
years, third-form students from primary schools in Cracow, who participated in the obligatory swimming classes
during the school year of 2002/2003. The classes took
place once a week at the swimming pool of the Uni
versity School of Physical Education. Each class lasted
40 minutes. The methods and forms of task implementa
tion were made uniform for all the classes. The children
were taught following the guidelines developed by
instructors from the Cracow School Sport Center.
During the first classes differences in readiness of some
pupils to continue curricular swimming classes in deep
water were noted. Complete results were obtained from
69 subjects; subjects with incomplete results were rejected.
Evaluation of swimming skills
In order to assess the level of basic swimming skills
a modified Swimming Skills Test (ST) consisting of ten
control exercises was used [6, 7, 20]. The exercises were
connected with swimming activities at the first level
of swimming instruction: introductory adaptation [21]
(Tab. 1). The assessment of basic swimming skills was
based on the absolute test result: 0 (unsuccessful) or 1 pt.
(successful) (maximum 10 pts., minimum 0 pts.).
94
Anxiety measurement
For the research purposes state anxiety (S-Anxiety)
(as opposed to trait anxiety – T-Anxiety) was measured.
For measuring state anxiety, a Polish adaptation of
Spielberger’s State-Trait Anxiety Inventory called “Self-evaluation Questionnaire” was used [22].
The Self-evaluation Questionnaire assessed the level
of anxiety understood as a temporary state in a student’s
behavior in the water. Since the questionnaire had mainly
been used for assessment of anxiety among adolescents
and adults, it was modified to be used as an evaluation
tool among the children in the present study [23, 24].
Two items (Item 13 – “I am distressed” and Item 14 –
“I am uptight”) were deleted from the original version.
During the preliminary study and during anxiety assessment a vast majority of children failed to comprehend
both statements and were hesitant to provide satisfactory answers. The remaining statements in the questionnaire were fully understood by the subjects. Considering
the subjects’ age (they had not quite developed their
writing and reading skills) the study was carried out by
way of interview rather than filling in the questionnaire.
The subjects were also given a chart, so they could mark
their feelings about the questionnaire statements. The
point values ranged from 18 to 72.
Research procedure
The assessment of state anxiety (S-A) was made
during at least six consecutive swimming classes. During
class a subject was evaluated after he or she came out
of the pool, and then after having answered the questions
resumed the class. The measurement of anxiety was made
by one interviewer (each interview was preceded with
detailed information about the questions to be asked).
To ensure the most objective results the interviewer
was not any of the children’s teachers. Anxiety measure
ments were not made during classes in which the swimming skills tests were carried out to avoid evaluation of
anxiety in the face of a completely different situation.
The level of swimming skills was assessed every five
classes.
Methodology
The statistical analysis involved calculation of the
arithmetic mean (x)
x and standard deviation (SD). The
correlation between the examined variables was calculated using the Pearson coefficient of correlation. The
significance of differences between the variables was de
termined using Student’s t-test (* p < 0.05, ** p < 0.01).
HUMAN MOVEMENT
Table 1. Control exercise set from the swimming skills test (ST)
Skill test
Control exercise
Face dip
dip face under water for at least 5 s
Opening eyes under water
count how many fingers you can see under water
Breathing while swimming
perform rhythmically 5 breathing cycles with prolonged exhalation
Back lying
keep lying on the back (without floating objects) for at least 5 s
Breast lying
keep lying on the chest (without floating objects) for at least 5 s
Under water orientation
retrieve 2–3 sunken objects
Elementary swimming
swim any style at least 5 m
Breast slide
swim in breast slide after taking off the wall at least 3 m without extra inhalation
Movement of lower limbs
swim at least 15 m with alternant lower limbs movement
Water jump
perform any leg jump from standing position from 0.70 m height
Table 2. Measurement of the level of state anxiety (S-A) and basic swimming skills (ST)
Examination number
I
Examination type
II
III
x
SD
t (2–1)
x
SD
t (3–2)
x
SD
ST
3.9
2.07
2.59**
6.1
3.12
0.05
7.1
3.32
2.96**
S-A
29.1
7.7
0.86
28.8
5.6
0.54
28.3
5.3
0.49
t (3–1)
** p < 0.01
Results
The mean results of three consecutive measurements
of state anxiety (S-A) and basic swimming skills (ST)
are presented in Table 2.
The mean results of the skills test increased gradually
from 3.9 after the first measurement to ~7.2 after the
third measurement (max 10.0 pts.). The increase rate
was, however, unsatisfactory considering the fact that
the evaluation concerned the basic swimming skills (first
level of instruction) and that the third examination was
carried out after 15 swimming classes.
The mean results of evaluation of the state anxiety
level follow a different dynamic. The results during the
first examination reached the maximum value of 29.1,
whereas the second and third examinations produced
lower results (28.3 pts.). The relatively steady level of
state anxiety is significantly correlated to the level of
swimming skills, as presented in Table 3.
The results obtained by the subjects show a strong
negative correlation between the level of anxiety and
the level of basic swimming skills, particularly after the
first examination (r1 = –0.76). There is also a significant
correlation between the anxiety level from the first examination (S-A1) and the results after the second and
third swimming skills tests (r1’ = –0.69 and r1’’ = –0.66),
which concurs the hypothesis put forward.
The correlation after the second and third examinations
(S-A2–ST2 and S-A3–ST3) ranged from weak (–0.34
after the 2nd examination) to average (–0.41 after the 3rd
examination). The third examination showed also a strong
correlation between S-A3 and the results of all three
swimming skills tests.
Next, the correlation between the level of anxiety and
the increase of swimming skills was assessed. The inTable 3. Correlation coefficients (r) between consecutive
state anxiety level (S-A) measurements and basic swimming skills (ST)
Test sequence
I. S-A1
II. S-A2
III. S-A3
ST 1
r1 = –0.76**
–0.31**
–0.33**
ST 2
r1' = – 0.69**
–0.34**
–0.41**
ST 3
r1" = – 0.66**
–0.32**
–0.41**
Marked values are statistically significant with ** p < 0.01.
95
HUMAN MOVEMENT
Table 4. Correlation coefficients (r) between consecutive
state anxiety level (S-A) measurements and increases
in swimming skills (ST)
I. S-A1
II. S-A2
III. S-A3
ST 2 – ST 1
–0.34**
–0.24*
–0.36**
ST3 – ST 2
– 0.31
–0.01
–0.05
ST 3 – ST 1
– 0.32**
–0.21
–0.36**
Marked values are statistically significant
with * p < 0.05, ** p < 0.01.
crement was defined as a difference between the results of
consecutive swimming skills tests (Tab. 4).
The results obtained show a weak but visible correlation between anxiety level S-A1 (1st examination) and
increase in swimming skills ST2–ST1 (r = –0.34), and
anxiety level S-A3 (3rd examination) and increases in
swimming skills ST3–ST1 (r = –0.36). Moreover, the
results after the first and third swimming skills tests
(ST3–ST1) also reveal a correlation between the rate of
acquisition of swimming skills and S-A1 (r = –0.32).
There was no significant correlation between the
anxiety level and the increase in swimming skills between
the 2nd and 3rd examinations.
Discussion
The significant role of anxiety in swimming learning
has been studied by different researchers [6, 13, 14]. Un
fortunately, since there has been no objective method of
measurement and assessment of the “fear of water”, most
of the studies have been based on observation and evalu
ation of child’s behavior in the water and are mainly di
rected towards prevention and alleviation of this unpleasant
feeling [25, 26]. It is, therefore, hard to relate the results of
the present study to the previous ones, although conclu
sions reached in the most crucial areas could be similar.
It is commonly believed that the main cause of anxiety
during learning to swim is the hazard of drowning. It
seems that identification of stimuli that accompany
swimming makes it difficult to disclose the actual cause
of anxiety (the issue is far more complex) [16, 27–29].
This is the reason why the term “fear in water” instead
of “fear of water” has been used, since the latter is imprecise and needs further verification. Slow progress in
learning could be the result of such factors as excessive
pace of instruction or inappropriate adjustment of instruc
tion to children’s mental capabilities. The mechanism
evoked resembles a vicious circle: a child who cannot
handle swimming successfully starts to experience ne96
gative emotions, including anxiety, which hinder the
learning process. As the child experiences more difficulties, the emotions grow stronger and seriously inhibit
swimming learning.
The above studies and observations confirm a high
correlation between the level of state anxiety experienced
in the water and swimming skills (especially at an early
stage of swimming learning). They also display a significant impact of anxiety on the swimming learning
progress in children.
Pupils who showed a higher level of anxiety, especially during the first swimming classes, achieved lower
results in the consecutive swimming skills tests (as
confirmed by the qualitative analysis). However, despite gradual improvement in swimming skills, the average
level of anxiety in children was reduced very slightly.
It seems that progress in swimming learning was
based on systematical repetition of series of exercises,
which (sooner or later) produced the desired effect of
acquisition of simple swimming skills. It, however, did
not have to signify relieving of anxiety tension. The
question remains whether this could be an explanation
for weakening the correlation between the learning
progress and the anxiety level after the second measurement. The relationship between the level of state anxiety and the level of trait anxiety, as distinguished by
Spielberger, is also of great importance. Intensification
of anxiety maintained on an almost steady level can
determine the limit of anxiety. If the limit is crossed,
anxiety can have a disorganizing impact on child’s behavior [5, 30, 31]. It can be assumed that there is some
kind of dynamic balance between the level of anxiety in
children in the water and the rate of acquisition of swimming skills. The children’s aversions and failures may
be consequences of disturbing this balance.
Thus, it should be remembered that the essence of
learning any motor skill is not merely the technical mas
tery of correct movements, but also guiding the learner
to use the acquired skills for his or her own benefit.
Instruction which is not directed towards a harmonious
psycho-physical development is not effective since it is
not beneficial to the learner. In extreme cases it can even
bring about serious psychical losses such as extreme
stress or a permanent trauma.
Conclusions
1. The children successfully acquired the curricular
swimming skills, which can be confirmed by the average
results of the swimming skills tests.
HUMAN MOVEMENT
2. Despite the observed learning progress in swimming the average level of anxiety was not dramatically
reduced.
3. The study of relationships between the anxiety level
and the level of swimming skills reveals a strong negative
correlation.
4. The initial level of anxiety may have a decisive
impact on further stages of the swimming learning process in children.
Considering the above results and observations it must
be emphasized that good and effective swimming learning
relies not only on an appropriate curriculum adapted to
the age and pace of child’s development, but also (and
perhaps first of all) on an individualized, sensitive and
flexible attitude of the instructor who introduces the child
to the world of unknown experiences.
References
1.Freud S., The origin and development of psychoanalysis [in
Polish]. Wydawnictwo Naukowe PWN, Warszawa 2000.
2.Kępiński A., Anxiety [in Polish]. PZWL, Warszawa 1987.
3.Rychta T., Fear and anxiety in sport [in Polish]. Kwartalnik
Metodyczno-Szkoleniowy, 1990, 1 69–78.
4.Cattel R.B., Anxiety and motivation: Theory and Crucial Experi
ments. In: Spielberger Ch.D. (ed.), Anxiety and behavior. Academic Press, New York 1966.
5.Spielberger C.D., Theory and research on anxiety. In: Spielberger Ch.D. (ed.), Anxiety and behavior. Academic Press, New
York 1966.
6.Bartkowiak E., Competitive swimming [in Polish]. COS, Warszawa 1999.
7.Wiesner W., Swim with us [in Polish]. Astrum, Wrocław 1997.
8.Kostova S., Swimming influence on the evolution of physical
capacity in children [in Bulgarian]. Vaprosi na Fiziceskata Kultura, 1987, 8, 28–32.
9.Salvan C., Lessons in water for 6-month to 5-year-old children
[in French]. L’ Education Physique et Sport, 1989, 43, 12–14.
10.Dybińska E., Teaching swimming to 1-year to 4-year-old children
[in Polish]. Kasper, Kraków 2000.
11. Brenstein G.A., Borchardt C.M., Perwien A.R., Anxiety disorders
in children and adolescents: a review of the past 10 years. J Am
Acad Child and Adolescent Psychiatry, 1996, 35, 1110–1119.
12.Ollendick T.H., Mattis S.G., King N.J., Panic in children and
adolescents: a review. J Child Psychology and Psychiatry, 1994,
35, 113–134.
13.Czabański B., Selected aspects of learning and teaching of sports
techniques [in Polish]. AWF, Wrocław 1998.
14.Czabański B., Fiłon M., Zatoń K., Introduction to swimming
theory [in Polish]. AWF, Wrocław 2003.
15.Gracz J., Sankowski T., Psychology of sport [in Polish]. AWF,
Poznań 1995.
16.Tyszkowa M., Aspects of mental resistance of children and
adolescents [in Polish]. PWN, Warszawa 1972.
17.Tyszkowa M., Behavior of schoolchildren in difficult situations
[in Polish]. PWN, Warszawa 1986.
18.Reiss S., McNally R.J., The expectancy model of fear. In: Reiss
S., Bootzin R.R. (eds.), Theoretical Issues in Behavior Therapy.
Academic Press, New York 1985.
19.Reiss S., Peterson R.A., Gursky D.M., McNally R.J., Anxiety
sensitivity, anxiety frequency and the prediction of fearfulness.
Beh Res Therapy, 1986, 24, 1–8.
20.Przybylski S., Waade B., Effects and durability of basic swimming education in 8–10-year-old children [in Polish]. Wrocław–
Srebrna Góra 1994, 41–48.
21.Dybińska E., Initial adaptation to the water environment in the
learning process of swimming skills [in Polish]. Kultura Fizyczna,
1997, 5–6, 14–17.
22.Wrześniewski K., Sosnowski T., State-Trait Anxiety Inventory
(STAI) – Polish adaptation [in Polish]. Warszawa 1996.
23.Brzeziński J., Methodology of psychological research [in Polish].
Wydawnictwo Naukowe PWN, Warszawa 1996.
24.Mayntz R., Holm K., Hubner P., Introduction to the methods of
empirical sociology [in Polish]. PWN, Warszawa 1985.
25.Fenczyn J., Anxiety and fear of deep water in young learning
swimmers [in Polish]. Wych Fiz Zdrow, 2003, 2, 21–23.
26.Dybińska E., Ostrowski A., Anxiety in 10-year-old children
swimming learners [in Polish]. Wych Fiz Zdrow, 2003, 2, 33–36.
27.Bochwic T.M., Anxiety in child [in Polish]. PZWL, Warszawa
1991.
28.Ranschburg J., Anxiety, anger, aggression [in Polish]. WSiP,
Warszawa 1980.
29.Schaw M.N., Children’s fears [in Polish]. Moderski i S-ka, Poznań 1995.
30.Bogdanowicz M., Child’s clinical psychology [in Polish]. WSiP,
Warszawa 1991.
31.Horney K., Neuroses and human development [in Polish]. PWN,
Warszawa 1978.
Paper received by the Editors: December 21, 2004.
Paper accepted for publication: April 5, 2005.
Witold Ziara
al. Jana Pawła II 84
37-571 Kraków, Poland
e-mail: witoldzus@op.pl
97
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2), 98–103
THE EFFECT OF TAI-CHI TRAINING ON SURROGATE INDEX
OF INSULIN RESISTANCE (HOMAIR) IN ELDERLY SUBJECTS
Łucja Pilaczyńska-Szcześniak1,*, Janusz Maciaszek2, Ewa Deskur-Śmielecka3,
Alicja Nowak1, Joanna Karolkiewicz1, Tadeusz Rychlewski1, Wiesław Osiński2
Chair of Physiology, Biochemistry and Hygiene, University School of Physical Education, Poznań, Poland
Chair of Theory of Physical Education, University School of Physical Education, Poznań, Poland
3
Department of Cardiac Rehabilitation, University School of Physical Education, Poznań, Poland
1
2
Abstract
Purpose. The aim of the study was to assess the influence of a 4-month physical training based on the Chinese Tai-Chi exercises on the
insulin resistance index HOMAIR (Homeostasis Model Assessment Insulin Resistance) in elderly men with various body mass indexes
(BMI). Basic procedures. The study population consisted of 118 healthy men, aged 62–83, who volunteered for the training program.
Subjects were randomly assigned to the training group or to the control (nontraining) group. Both groups were further divided into
subgroups depending on BMI: subgroup with normal BMI, overweight subgroup and obese subgroup. The training program lasted 4
months (February–May) and consisted of two 45-minute sessions of the Tai-Chi prophylactic-therapeutic exercises weekly. The training
was aimed at maintaining and increasing fitness in the elderly, with special attention paid to joint mobility and coordination of movements
(quickness and precision of movements). The intensity of the exercises was selected so that the heart rate did not exceed 110–120 beats
per minute. Heart rate was monitored during each exercise session with a heart rate monitor (Accurex Plus, Polar, Finland). Before
entering the training program and after completing it blood samples for biochemical analyses were taken from the antecubital vein
after an overnight fast (between 7 a.m. and 8 a.m.). Serum insulin concentrations were evaluated with an immunoradiometric assay kit
(INS-IRMA, BioSource S.A., Belgium). Serum glucose concentrations were determined with Liquick Cor-GLUCOSE assay kit (Cormay, cat.
No. 2-202, Poland). The insulin sensitivity index HOMAIR was calculated using the mathematical formula described by Matthews and
collaborators [14]. Main findings. Insulin sensitivity index in persons with normal body mass was 2.8 ± 1.58, in the overweight subjects
3.1 ± 1.41, and in the obese men 4.4 ± 2.86 (mean values calculated for the entire subgroups, including both training and nontraining persons, at the beginning of the study). The 4-month training based on the Tai-Chi exercises resulted in significant decreases in serum immuno
radioactive insulin concentrations, glucose levels and HOMAIR in the overweight subgroup and in the obese subgroup. No significant
changes in these parameters were observed over the study period in the subjects with normal body mass index. Conclusions. The results
of the present study indicate that obesity is associated with insulin resistance. Increased physical activity improves insulin sensitivity
in elderly men and may be regarded as a non-pharmacological, preventive method of the civilization-related metabolic disorders.
Key words: elderly men, body mass, overweight, obesity, physical activity, HOMAIR
Introduction
Insulin resistance is defined as an attenuated action of
insulin on the glucose transport and metabolism in skeletal muscle and other target tissues. The main metabolic
consequence of the insulin resistance is hyperglycemia
[1, 2]. To compensate for the peripheral tissue insulin
resistance, islet beta cells increase secretion of this hormone
and glucose concentration in the blood initially remains
within the normal range. Further increase of insulin resis
tance and desensitization of beta cells to insulin lead to
impaired glucose tolerance and type 2 diabetes [3, 4]. It
is well known that impaired glucose tolerance and hyper
* Corresponding author.
98
insulinemia play an important role in the pathogenesis
of dyslipidemia, obesity, ischemic heart disease and
hypertension [4, 5]. It has also been proven that insulin
resistance is related to age [6, 7]. This was proved by
investigations in which Hyperinsulinemic euglicemic
clamp in combination with infused marked glucose ([3H]-glucose) was used [8]. The relation between elderly age
and reduced insulin effect has recently been confirmed
by the European Group for the Study of Insulin Resistance, which revealed reduced age-dependent effect of
insulin in 1146 inhabitants of the Caucasus, both men (p
< 0.01) and women (p < 0.07) [9]. Hyperglycemia, which
is the effect of hyperinsulinemia, results in increased generation of free radicals (ROS) in glucose autooxidation
and protein glycation reactions and in the creation of advanced end products of glycation (AGEs), thus upsetting
the dynamic equilibrium between pro- and antioxidants.
HUMAN MOVEMENT
Ł. Pilaczyńska-Szcześniak et al., The effect of Tai-Chi training on index HOMAIR
As is reported by Chen et al. [10] increased ROS genera
tion in beta-pancreas mitochondria exposed to increased
glucose concentration, contributes to the attenuation of
the first phase of insulin secretion. It has also been found
that glucose concentration higher than reference values
affects the signal transmission route through the activation
of protein kinase C (PKC) and increased concrntration of
diacylglycerol (DAG), which induces diabetic-vascular
and neurological changes.
Several factors, such as enhanced physical activity,
may reduce insulin resistance and hyperinsulinemia and
therefore increase insulin sensitivity [11]. Investigations
conducted by this author have proved that increased
physical activity favourably affects the sensitivity of beta-pancreas cells to glucose and insulin sensitivity of skeletal muscles to insulin. Although the precise mechanism
of this favourable effect has not been fully explained
yet, results of investigations conducted by Henriksen
et al. [11] have proved that increased physical activity
contributes to increased expression of GLUT-4 protein
in muscular cells and its translocation from intracellular
space to cytoplasmatic membrane. On this basis a hypo
thesis can be advanced that endurance training increases
insulin sensitivity of target cells through the increase of
protein phosphorylase processes and the activation of
the 3-kinase insulin/phosphatidylinositol tract (P13K).
Our earlier investigations [12] have also proved that
a 3-week physical training at 90% of the ventilatory
threshold in patients with ischemic heart disease and
hyperinsulinemia significantly decreased insulin concentrations in the blood and improved the affinity of
the insulin receptor. The aim of the present study was to
assess the influence of a 4-month physical training based
on the Chinese Tai-Chi exercises on the insulin resistance
index HOMAIR (Homeostasis Model Assessment Insulin
Resistance) in a group of elderly men with various body
mass indexes (BMI).
The study population consisted of 118 healthy men
aged 62–83, members of the Senior Club in Poznań,
who volunteered for the training program. All subjects
were randomly assigned to the training group or to the
control (nontraining) group. Both groups were further
divided into subgroups depending on the body mass
index: subgroup with normal BMI (20.1–25.0 kg/m2),
overweight subgroup (BMI 25.1–30.0 kg/m2) and obese
subgroup (BMI > 30.1 kg/m2). All subjects gave their
informed consent to participate in the study.
The training program lasted 4 months (from February
to May) and consisted of two 45-minute sessions of the
Chinese Tai-Chi prophylactic-therapeutic exercises weekly.
Overall, 37 training sessions were carried out. The training was aimed at maintaining and increasing fitness in
the elderly. Special attention was paid to joint mobility
and coordination of movements (quickness and precision
of movements). Exercises improving static and dynamic
balance of the body and respiratory exercises were also
included in the training program. The programme consisted of a 10 min warm up exercise (including stretching
and balancing exercise), 30 min of Tai-Chi practice,
and was followed by 5 min of cool down exercises.
Subjects imitated the instructor’s motions and postures
at the same speed. During sessions, the instructor constantly monitored the subjects and corrected the body
position, joint angles and from-to-from transition. In
accordance with the recommendations for subjects over 60
performing average physical activity [13], the intensity
of the exercises was selected so that the heart rate did
not exceed 110–120 beats per minute. Heart rate was
monitored during each exercise session with a heart rate
monitor (Accurex Plus, Polar, Finland). During the study
period, both the training and non-training groups were
not recommended to change their lifestyle, in particular
their nutrition habits. No additional physical activity was
recommended either.
Before entering the training program and after completing it body composition was assessed in each subject
with an electric bioimpedance method (101/S analyzer,
Akern, Italy) and blood samples for biochemical analyses
were collected. The blood samples were taken from the
antecubital vein after an overnight fast (between 7 a.m.
and 8 a.m.) and centrifuged immediately to separate
serum from erythrocytes. Serum samples were stored at
–28°C until analysis.
Serum insulin concentrations were evaluated with an
immunoradiometric assay kit (INS-IRMA, BioSource
S.A., Belgium) using tubes coated with monoclonal
anti-insulin capture antibodies and signal antibodies labeled with 125Iodine. The radioactivity bound to the tube
reflected the antigen concentration. The radioactivity
was measured with SCALAR A-22-M gamma analyzer
(Polon, Poland). The intra-assay error was < 5.7% and
the inter-assay error was < 6.4%.
Serum glucose concentrations were determined with
Liquick Cor-GLUCOSE assay kit (Cormay, cat. No. 2-202,
Poland). The method used the reaction catalyzed by glucose oxidase (GOD), which led to the formation of glu99
HUMAN MOVEMENT
conic acid and hydrogen peroxide. In the presence of
4-aminoantipyrine peroxidase (POD) hydrogen peroxide
reacted with phenol and 4-aminoantipyrine producing
red-colored complex 4-(p-benzochinonomonoimino)-phe
nazone. The intensity of the color was proportional to the
glucose concentration. The absorbance of the samples
was measured at 500 nm with SEMCO S91E spectrophotometer (Poland).
The insulin sensitivity index HOMAIR was calculated
using the mathematical formula described by Matthews
and collaborators [14]:
HOMAIR = CINS (μU/mL) · CGLUC (mmol/L)/22.5.
The protocol of the study was accepted by the local
Ethics Committee.
Table 1. Comparative analysis of the results obtained
before and after the study period in the subgroups
with normal body mass (x ± SD)
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
Results
Tables 1–3 show the results of the within-group com
parisons in subgroups (training and nontraining) with
normal BMI (Tab. 1), overweight subjects (Tab. 2) and
obese persons (Tab. 3). Among men with normal BMI,
both in the training group and in the control group, the
results obtained at the end of the study did not significantly differ from the initial ones (Tab. 1). In the overweight
subjects, the training program resulted in significant
decreases in glucose concentrations and HOMAIR (P
< 0.01), and immunoreactive insulin levels (P < 0.05).
No such differences were found in the control group
(Tab. 2). In the obese men, the training program resulted
in significant decreases in glucose concentrations, insulin
levels and HOMAIR (P < 0.05). These parameters did
not change over the study period in the control group.
Before implementing the training program, the
Spearman’s rank correlation analysis showed significant
correlations between glucose concentration and BMI (r
= 0.524, P < 0.05) and between insulin level and body
mass (r = 0.536, P < 0.05) in the obese subjects assigned
to the training group.
After completing the training program, there were
significant correlations between insulin level and BMI
(r = 0.425, P < 0.05), between HOMAIR and body mass
(r = 0.422, P < 0.05) and between HOMAIR and BMI
100
after
69.6 ± 6.7
165.7 ± 5.6
65.9 ± 5.2
23.9 ± 1.0
17.2 ± 4.5
26.6 ± 7.63
6.0 ± 1.2
8.9 ± 1.6
2.4 ± 0.6
67.7 ± 7.3
24.2 ± 1.5
17.7 ± 4.7
26.1 ± 6.27
5.8 ± 0.9
7.7 ± 2.0
2.0 ± 2.1
0.123
0.767
0.859
0.894
0.929
0.139
0.722
Control group (n = 9)
Statistical analyses
All statistical analyses were performed with Statis
tica v. 6.0 software package. The differences between
paired variables were investigated with Wilcoxon test
Spearman’s rank analysis was used to calculate correlation coefficients. P value < 0.05 was considered
statistically significant.
before
Wilcoxon
test
P
Training group (n = 11)
Parameter
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
73.3 ± 3.9
171.5 ± 3.1
68.5 ± 4.5
23.3 ± 1.3
18.1 ± 3.24
26.4 ± 4.0
6.0 ± 0.7
11.1±3.0
3.0 ± 0.8
68.4 ± 5.4
23.3 ± 1.3
17.7 ± 2.0
25.4 ± 2.5
5.9 ± 0.7
10.6 ± 3.8
2.6 ± 0.7
0.401
0.889
1.000
0.343
0.779
1.000
0.401
BMI – body mass index, FM – fat mass,
HOMAIR – Homeostasis Model Assessment Insulin Resistance
(r = 0.385, P < 0.05) in the overweight men. Among
subjects in the control group, there were significant
correlations between insulin concentration and fat
mass (expressed in kilograms; r = 0.703, P < 0.05) in
the subgroup with normal BMI, and between glucose
concentration and body mass (r = 0.415, P < 0.05), between HOMAIR and body mass (r = 0.333, P < 0.05) and
between HOMAIR and fat mass (r = 0.331, P < 0.05) in
the overweight subgroup.
Discussion
The present study investigated insulin resistance in
the elderly and the potential influence of physical activity
on this parameter. To assess insulin resistance, we used
the index HOMAIR proposed by Matthews et al. [14]. In
their original work, the normal range for HOMAIR in
population with normal body mass was 1.25–1.41. Other
authors found higher values of HOMAIR in healthy, lean
subjects: Chevenne et al. [15] – 2.1, Yeni-Komshian et al.
[16] – 2.7, Ascaso et al. [17] – 3.8. In our study, insulin
HUMAN MOVEMENT
before and after the study period in the overweight
subgroups (x ± SD)
Parameter
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
before
69.3 ± 6.3
170.0 ± 6.9
78.6 ± 7.9
27.2 ± 1.5
23.9 ± 4.2
30.1 ± 4.6
6.4 ± 1.5
10.5 ± 3.4
3.0 ± 1.1
after
79.3 ± 9.0
27.4 ± 2.0
24.7 ± 5.0
30.5 ± 4.1
6.0 ± 1.1
9.2 ± 2.8
2.4 ± 0.8
Wilcoxon
test
P
0.643
0.587
0.459
0.970
0.001**
0.030*
0.002**
before and after the study period in the obese subgroups
(x ± SD)
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
69.3 ± 5.8
171.7 ± 6.4
81.4 ± 7.2
27.6 ± 1.5
25.7 ± 4.4
31.2 ± 4.9
5.9 ± 0.9
11.7 ± 4.5
3.1 ± 1.6
80.6 ± 7.3
27.3 ± 1.8
25.4 ± 4.8
30.9 ± 5.1
5.7 ± 0.8
11.2 ± 3.8
2.9 ± 1.2
before
after
Wilcoxon
test
P
67.5 ± 4.4
169.6 ± 5.3
94.5 ± 9.3
32.8 ± 2.0
33.5 ± 6.7
35.2 ± 4.2
6.8 ± 1.9
14.5 ± 6.3
4.6 ± 3.5
94.6 ± 9.60
32.8 ± 2.07
31.8 ± 6.45
33.4 ± 4.21
5.9 ± 1.03
10.8 ± 4.14
3.0 ± 1.56
0.950
0.850
0.136
0.080
0.019*
0.008**
0.013*
Parameter
0.156
0.052
0.587
0.713
0.361
0.107
0.127
Age (years)
Height (cm)
Body mass (kg)
BMI (kg/m2)
FM (kg)
FM (%)
Glucose (mmol/L)
Insulin (µU/mL)
HOMAIR
68.7 ± 6.0
170.4 ± 5.4
93.6 ± 8.6
32.2 ± 2.8
32.6 ± 6.3
34.7 ± 4.4
6.6 ± 1.8
14.5 ± 7.0
4.2 ± 2.3
92.5 ± 9.7
31.7 ± 3.1
31.8 ± 6.3
33.9 ± 4.4
6.3 ± 1.0
13.9 ± 4.9
3.8 ± 1.4
0.298
0.127
0.173
0.249
0.135
0.086*
0.074*
BMI – body mass index, FM – fat mass, HOMAIR – Homeostasis
Model Assessment Insulin Resistance, * p < 0.05, ** p <0.01
BMI – body mass index, FM – fat mass, HOMAIR – Homeostasis
Model Assessment Insulin Resistance, * p < 0.05, ** p < 0.01
resistance index varied depending on the body mass index
(BMI). In persons with normal body mass, HOMAIR was
2.8 ± 1.58 and was similar to the values reported by Yeni-Komshian and collaborators [16]. In the overweight subjects HOMAIR was 3.1 ± 1.41, and in the obese men 4.4 ±
2.86 (mean values calculated for the entire subgroups,
including both training and nontraining persons, at the
beginning of the study). These findings indicate that in
subjects of similar age (the mean age in study subgroups
was 71.3 ± 5.80, 69.3 ± 5.99 and 68.2 ± 5.3 years and was
not significantly different between subjects with correct
body mass and obese subjects and between overweight
and obese subjects) the value of HOMAIR depends mainly
on their body mass. The relationship between HOMAIR
and body mass index was further confirmed by Spearman’s rank correlation. The correlation coefficient in the
overweight subjects was 0.385 (P < 0.05), and in the
obese persons 0.423 (P < 0.01).
The results of the present study suggest that the increase in physical activity in overweight or obese, elder-
ly men may favorably influence disturbances leading to
insulin resistance even if body mass remains unreduced
(Tab. 2 and 3). It should also be underlined that the applied
kinesitherapy did not affect glucose or insulin concentrations in the subjects with normal body mass index (Tab.
1). Henriksen [11] and Chibalin and collaborators [18]
showed that the favorable impact of the increased physical activity might be due to the enhanced expression
of the Glut-4 glucose transporter isoform or increased
expression and/or function of the proximal elements in
the signaling cascade comprising the insulin receptor
and the insulin receptor substrate-1 (IRS-1). In our previous study we found that physical training at 70% of the
VO2max increased insulin receptor affinity and decreased
serum fasting insulin levels in obese youth [19]. Moreover, we observed higher insulin receptor affinity in the
trained subjects in comparison with people performing
moderate physical activity [20]. These findings are consistent with the results of the present study. We have
found a significant decrease in the fasting insulin con101
HUMAN MOVEMENT
Table 4. Analysis of Kruskal-Wallis ANOVA of selected
parameters in training and non-training groups
in two study periods
Parameter
term I
value H
Glucose
(mmol/L)
Insulin
(µU/mL)
HOMAIR
term II
value H
P
0.612
0.930
0.628
10.071
0.006**
4,716
0.095
8.382
0.015*
0.351
0.839
0.983
P
Non-training group (n = 65)
Glucose
(mmol/L)
Insulin
(µU/mL)
HOMAIR
0.805
0.669
0.801
0.670
2.672
0.263
2.190
0.335
4.663
0.097
2.510
0.285
* p < 0.05, ** p < 0.01
centrations after the training program in the overweight
(Tab. 2) and obese (Tab. 3) subgroups. The decrease in
the insulin levels may directly depend on the nervous
system. Physical exercise is associated with increased
sympathetic and decreased parasympathetic impulsation,
which in turn is the main mechanism responsible for the
inhibition of the insulin secretion during exercise [15,
21, 22]. The decreased insulin levels may also be due to
the increased uptake of the non-esterified fatty acids
during exercise [23]. Goodpaster et al. [24] found that
obese persons (particularly those with abdominal obesity) showed decreased ability to utilize fatty acids at
rest in comparison with lean subjects due to the decreased
activity of carnitine acyltransferase. Moreover, low
density of β2-adrenergic receptors on adipocytes in the
abdominal fatty tissue, or decreased blood flow in this
tissue may contribute to the lipolytic resistance to catecholamines observed in subjects with abdominal obesity [25]. Despite some controversies about the increase
in the adipose tissue blood flow during physical exercise, it is known that decrease in the body mass and the
amount of fatty tissue leads to an enhancement of this flow
resulting in a greater availability and utilization of free
fatty acids by working muscles, especially if exercise is
low to moderate (25 to 65% of VO2max).
Gumbiner et al, [26], and Ferrannini et al, [9] found
that aging was associated with an impairment in the insulin-dependent glucose transport into skeletal muscles,
and that insulin resistance in the elderly was a result of
102
both receptor and post-receptor defect. Chronic
hyperglycemia and hyperinsulinemia, being after-effects
of the insulin resistance, induce peroxidation processes
involved in the aging [27]. In the present study we have
shown that aerobic physical activity (heart rate 110–120
bpm) favorably influences HOMAIR in healthy, elderly
men (Tab. 4). These findings indicate that physical activity may play an important role in the prevention of
insulin resistance and its consequences in the elderly.
We observed a significant decrease in the immunoreactive insulin levels and HOMAIR over the 4-month
study period in the obese subjects assigned to the control
group (Tab. 2 and 3). In contrast, glucose concentrations
in this subgroup remained unchanged. These favorable
changes most probably are the result of more active
lifestyle in the warmer season, conducive to frequent
walking, or impossible to eliminate contacts with subjects
assigned to the training group. In other control subgroups
(overweight and with normal body mass), the insulin
resistance parameters tended to decrease during the study
period (P = ns). These findings seem to support the hypo
thesis that the spontaneous physical activity in our study
population increased because of the warmer season.
Conclusions
The results of the present study confirm that in persons
of similar age insulin resistance increases along with
body mass. Physical activity increases insulin sensitivity
in elderly men and should be regarded as a non-pharma
cological, preventive method of the civilization-related
metabolic disorders.
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myocardial infarction. J Cardiopul Rehab, 1999, 9, 98–105.
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Paper received by the Editors: February 12, 2005.
Paper accepted for publication: June 20, 2005.
Łucja Pilaczyńska-Szcześniak
Zakład Higieny
ul. Królowej Jadwigi 27/39
61-871 Poznań, Poland
e-mail: stefan@szczesniak-tlumacz.com.pl
103
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2005, vol. 6 (2), 104–111
THE ISSUE OF GENE DOPING
Daniel P. Potaczek
Department of Medicine, Jagiellonian University School of Medicine, Kraków, Poland
Abstract
Increasing competition in sports is followed by an ever growing use of doping. Classical doping methods have many unwanted side
effects and are now relatively easy to detect. In addition, more efficacious methods of improving body performance are sought. It is
known that individual composition of genes is responsible for the performance profile and predispositions to become an athlete. We
know that some genes are particularly significant for athletic performance. It is thought that methods of gene doping are going to be
developed in the nearest future. Current possibilities of application of gene therapy have been extensively studied. At first, the results
of tests on animals were encouraging, but when applied in humans gene transfer has yielded different results. Some of the studies
on gene therapy in humans led to unwanted, serious and even fatal effects. However, most of the tests were successful. There is
a great amount of ongoing research concerning application of gene transfer in patients with muscular dystrophies and anemia. In the
nearest future, gene therapy could also be useful in sports medicine and, if used in inappropriate ways, as a method of doping. The
use of gene doping could lead to a local expression of desirable protein controlled by natural regulatory mechanisms. It could result
in lower toxicity, and also be more difficult to detect. The potential development of gene doping concerns possible use of erythropoietin,
vascular endothelial growth factor, endorphins, insulin-like growth factor-1 and myostatin.
Key words: genes, gene transfer, vectors, doping, gene doping
Introduction
In recent years more and more attention has been paid
to the issue of gene doping. The present study aims at the
following facets of gene doping: its definition, significance, scientific justification, connection between genetic
variability and efficiency of the human body, current possi
bilities of developing methodology of gene therapy, tissue
engineering as well as various controversies and directions
of possible development of gene doping in the future.
Definition of gene doping
According to the World Anti-Doping Agency (WADA)
gene or cell doping is defined as the non-therapeutic use
of genes, genetic elements and/or cells that have the
capacity to enhance athletic performance. This definition
was included in the WADA 2004 Prohibited List [1], which
is a proof of a real threat that may be posed by applica
tion of methods of molecular biology, gene therapy and
tissue engineering in sport doping. Gene doping has been
the subject of a heated debate in biomedical circles for
some years. Already, it has been discussed by the WADA,
United States Anti-Doping Agency (USADA) and the
Netherlands Centre for Doping Affairs (NeCeDo). For three
years, one of the sessions of the Annual Convention of
the American Association of the Advancement of Science
104
(AAAS) has been devoted to gene doping (Denver, CO
2003; Seattle, WA 2004). The author of the present paper
participated in a series of gene doping workshops held
at the 38th Annual Convention of the European Society
of Clinical Investigation (ESCI) in Utrecht, the Netherlands, on April 17, 2004.
Genes and sport
There is no doubt that the individual set of genes in
each of us determines our maximum efficiency and capa
bilities of our body. Proper training allows us to bring
them all out, however, only in the confines of information
contained in our genome. There are certain gene sequen
ces which clearly predestine individuals to achieve more
in a given area of sport. It can be illustrated by the cases
of long-distance runners from Ethiopia or Kenya or the
Finnish ski runner Eero Mäntyranta, who won two Olympic medals at the Innsbruck Games. The latter carried
a mutation in the erythropoietin (Epo) receptor gene –
which causes an increase in the number of erythrocytes
– contributing to his outstanding endurance and sports
performance [2–4].
Understanding and recognition of the role of genes in
shaping potential capabilities of the human body led to
the drawing of a human gene map for performance and
HUMAN MOVEMENT
D.P. Potaczek, The issue of gene doping
health-related fitness phenotypes [5]. The publication
covered the genes recognized before 2000 and has been
updated two times [6, 7].
Although the variability of these genes has been exten
sively described, particularly interesting seems to be angio
tensin-converting enzyme (ACE) gene insertion/deletion
(I/D) polymorphism. This genetic variability affects the
size of training-related left-ventricular hypertrophy, but
also seems to exert an impact on skeletal muscle strength
and endurance, metabolic efficiency and maximal aerobic
capacity [8–10]. Although the results of different studies
may still seem controversial, the allelic variants of ACE
gene I/D polymorphism appear to reveal a different distri
bution in groups of elite athletes performing different sports
as compared with subjects from control groups [8, 11].
To sum up, natural variability indicates genes influencing sports capabilities, and suggests possibilities of
genetic manipulations aimed at genetic transformations.
The genes are transferred into cells using two kinds
of special carriers called viral and non-viral vectors. Out
of the former, the most frequently used are retroviral
vectors, adenoviruses, adeno-associated viruses (AAV)
and herpes simplex viruses. The latter consist of transfers
of “naked” deoxyribonucleic acid (DNA), lipid-coated
DNA (liposomes), DNA-lipid complexes (lipoplexes)
or cationic polymer-coated DNA (polyplexes). The
genes are transferred with attached regulatory elements,
called promoters, responsible for effectiveness of expression. Their activity can be controlled from the outside
by administering a specific substance, e.g. doxycycline
A
Why gene doping?
In the times of constant and uncontrollable pursuit
of success and financial benefits the problem of gene
doping seems unavoidable. Frequent disqualifications
of athletes on the grounds of illegal doping are merely
the tip of the iceberg, and discouragement of at least a
few athletes from using doping seems unattainable. For
this reason, more effective, safer and harder to detect
doping methods, such as gene doping, will be sought.
Although, at first glance, the gene doping appears to be
less predictable (thus less safe) than classical pharmacological doping, it allows achieving desired effects at
the site of administration. Additionally, gene doping
remains under natural physiological regulation and ifs
effects can be reached with lower concentrations of the
active substance. Detection of gene doping can be very
difficult [2, 12–15]. It seems that during the next couple
of years, or perhaps even at the 2008 Summer Olympic
Games in Beijing, we may witness an appearance of
genetically modified athletes [2, 13–16].
Gene therapy
Gene therapy consists in transformation of the genetic
information in somatic cells or germinal cells (already
prohibited).
There are two strategies of gene therapy: in vivo, via
transfer of a gene directly into the cells in the system
(Fig. 1A); and ex vivo, via transfer of a gene into cells
taken and cultured outside the system followed by repo
pulation of the transformed cells (Fig. 1B).
B
A)
B
A
C
D
B)
Figure 1. Strategies of gene therapy
A. In vivo gene therapy via muscular transfer of Insulin-like
Growth Factor-1 (IGF-1). A – transfer of IGF-1 gene to skeletal
muscle cells, B – increase in muscle mass,
B. Ex vivo gene therapy via transfer of gene of gamma chain lymphocytic cytokine receptor to CD34+ bone marrow
progenitor cells in patients suffering from Severe Combined
Immunodeficiency (SCID). A – taking CD34+ progenitor
cells from the patient’s bone marrow, B – transfer of gamma
chain gene to cells, C – repopulation of transformed cells,
D – increase in patient’s immunity
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[17, 18]. Detailed characteristics of the vectors are,
however, beyond the scope of the present study.
Pros and cons of gene therapy
Initially, it appeared as if gene therapy would be highly
successful. Numerous successful tests on animals indicated possible success on humans. No transmission of
the AAV vector to germinal cells was observed following
delivery of the recombinant vector into human skeletal
muscle and the hepatic artery [19]. There was no wild-type virus reactivation and replication in peripheral blood
following local, intratumoral (non-small cell lung cancer)
transfer of the recombinant adenoviral vector [20]. Some
studies reported on achievement of biological effects
following gene therapy. Kay et al. [21] provided evidence
for gene expression of factor IX following intramuscular
administration of a recombinant AAV vector in hemophilia B patients. They noted an increase in factor IX
concentrations and a decrease in the frequency of factor
IX infusions in those patients. Neither transmission of
the vector sequence to the germinal cells, nor presence
of factor IX antibodies was observed. Another research
team applied gene therapy in treatment of a fatal congenital disease called Severe Combined Immunodeficiency (SCID). SCID is caused by a mutation of a chromosome X gene that encodes the gamma chain. The latter
is an essential component of cytokine receptors which
determine proper systemic immunity [22]. The correct
gamma chain gene was transferred ex vivo into CD34+
bone marrow progenitor cells using a retroviral vector.
After implanting the modified cells a sustained correction of immunodeficiency was achieved in four out of
five patients in therapy. No life-threatening side effects
were noticed. Then, the gene therapy was given to other
patients, unfortunately after three years one of them
developed T-cell leukemia [23]. It was followed by yet
another similar cancer case later on. In both cases the
causing factor turned to be retroviral vector integration
in chromosome 11 evoking an uncontrollable expression
of LMO-2 oncogene, which, as has been ascertained, may
cause childhood leukemia [24]. Further research revealed
such insertion in a third patient from the group under
study, who, however, did not develop leukemia [25].
The above case is not the only known serious complication following gene therapy. In the United States, in
the late 1990s, an experiment was carried out consisting in
application of adenoviral gene transfer in congenital ornithine transcarbamylase deficiency patients. One of the
treated patients developed a fatal systemic inflammatory
response syndrome [26]. The events described above
106
evoked a debate in the scientific community and resulted
in temporary discontinuation of gene therapy research in
humans. In most countries research concerning retroviral
gene therapy was suspended.
A certain discord becomes also noticeable between
Europe and the United States when it comes to gene the
rapy. In the latter a very cautious and skeptical approach
towards gene therapy dominates. The National Institute
of Health (NIH) and the Food and Drug Administration
(FDA), for instance, approve of gene therapy in X-linked SCID only when there is no alternative treatment
available. They allow research on retroviral gene therapy only after close scrutiny of individual cases [27]. A
critical and cautious approach to gene therapy can also
be observed in other treatment trials, e.g. in Parkinson’s
disease. This seems quite justified in view of the therapy
failures mentioned above as well as overenthusiastic attitudes of certain scientific communities, based on results
of preclinical studies [28].
In most European countries the temporary ban on
retroviral gene therapy research has been lifted. On the
whole, European experts seem to be more favorably
and enthusiastically disposed to this kind of research.
General opinion is that successful results in therapy
prevail against the risk of retroviral gene therapy in X-linked SCID patients. They suggest implementation of
the so-called molecular monitoring and possible use of
non-retroviral vectors [29]. It must be noted, however,
that it is the opinion of researchers directly involved in
the studies described on gene therapy. On the other hand,
U.S. scientists are of the opinion that gene therapy, like
any other novel treatment, may also reveal shortcomings,
but it should not be disqualified as a therapeutic possibility [30]. Gene therapy offers possibilities of treatment
entailing a considerable risk, however, as in the case of
SCID being the sole option, this may have a long-term
and discernible effect [30, 31]. It can be justified in view
of consecutive therapeutic successes in X-linked SCID
patients [32] and previous advancements in treatment
of other SCID variants [33]. In conclusion, although
there have been no routine and verified methods of gene
therapy (with no possible side effects or potential health
hazards), individual clinical cases require careful consideration of all possible risks linked to application of gene
therapy and balancing them with all possible benefits.
Gene therapy in sport
Over the last two decades a great improvement has
been observed in treatment of sport-related injuries.
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New and advanced operative techniques and rehabilitation methods have been developed. Nevertheless,
therapy of certain injuries such as skeletal muscle
injuries, tendon and ligament ruptures, meniscus and
articular cartilage injuries or delayed bone union still
remains unsatisfactory. Rapid development of gene
therapy and genetic engineering offers (considering the
aforementioned drawbacks and risks) a possibility of
effective treatment of sport-related injuries based on
such methods. Application of gene therapy consisting of
a transfer of genes encoding proteins can be a form of
potential treatment that allows achieving a local, proper
concentration of the growth factor at the injury site and
therefore enhancement of healing. The growth factors
that deserve particular consideration in the context of
their application in sport medicine include the insulin-like growth factor (IGF-1), basic fibroblast growth
factor (bFGF), nerve growth factor (NGF), transforming
growth factor-β (TGF-β), bone morphogenic protein
(BMP) group, platelet-derived growth factor (PDGF)
group, epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF). The tissue engineering
methods combined with gene therapy can be potentially
applied in regeneration of damaged tissues following
sport-related injuries [34, 35].
Prospective development of gene doping
Unfortunately, the results of research into the development of gene therapy of various disease entities can
also be applied in gene doping. The most plausible prospects of such “promising developments” are presented
below. They include possible application of Epo, VEGF,
opioids, IGF-1 and myostatin (Fig. 2).
Erythropoietin (Epo)
Epo, synthesized in the kidney, is a survival factor
for erythroid progenitor cells, preventing their apoptosis.
It conditions the production of new erythrocytes, which
enhances the aerobic capacity. Infusion of Epo protein
is administered in anemia patients suffering from neoplastic diseases, long-standing, devastating contagious
diseases such as AIDS as well as the anemia associated
with renal insufficiency. As it enhances the supply of oxy
gen to tissues, Epo may also be used in sport as a stimulant.
There are ongoing studies concerning gene therapy
using Epo. AAV-mediated intramuscular delivery of Epo
in baboons led to sustained elevation of Epo in circulating blood and concurrent elevation of the hematocrit
value (indicator of erythrocyte volume in blood) for
A
D
B
E
C
Figure 2. Potential developments in gene doping
A – intraspinal transfer of opoids gene for long-lasting allevia
tion of pain, B – transfer encoding Vascular Endothelial
Growth Factor (VEGF) gene to enhance vascularization and
perfusion of myocardium and other tissues, C – transfer of
Epo encoding gene to enhance production of red blood cells,
D – transfer of Insulin-like Growth Factor-1 (IGF-1) gene
to increase muscle mass and strength, E – transfer of genes
encoding myostatin inhibitors to improve muscle mass
twenty-eight weeks [36]. Intramuscular administration
and electroporation-mediated transfer of the plasmid encoding Epo gene in normal rats and rats with severe renal
insufficiency resulted in an 11-month- and 15-monthexpression of Epo gene and associated eryhthropoiesis.
The uremic rats developed recombinant Epo-induced
arterial hypertension [37]. The AAV-mediated intramus
cular delivery of Epo in mice resulted in Epo expression
permitting reversal of anemia and left-ventricular hyper
trophy (a frequent complication in anemia). Differences
in the results were observed, depending on the promoter
used. Application of the constitutive cytomegaloviral
promoter led to fatal polycythemia (abnormal increase in
red blood cells), whereas the usage of hypoxia response
element promoter allowed anemia treatment by achieving the physiological number of erythrocytes in a blood
unit. The above is an example of a mechanism regulating
close-to-physiological gene expression, which suggests
a possibility of a safer and more-controlled application
of gene therapy in clinical conditions [38].
Unfortunately, not all the studies so far have yielded
such promising results. An AAV-mediated intramuscular
delivery of Epo in macaques led to autoimmune anemia
induced by anti-Epo antibodies [39]. A similar AAV-me
diated intramuscular transfer of Epo with a doxycycline107
HUMAN MOVEMENT
-regulated promoter system in macaques led to anemia
with anti-Epo antibodies [40].
In summary, there is still much to be done before
recombinant-Epo gene therapy can enter the phase of
clinical trials.
Vascular Endothelial Growth Factor
The VEGF is the chief protein in angiogenesis in phy
siological and pathological conditions. Since the VEGF
group stimulates the growth of new blood vessels, there
have been attempts to use the VEGF gene therapy in
coronary artery disease (CAD) and peripheral artery
occlusive disease (PAOD) which lead to thickening and
obstructing arteries by artherosclerotic plaques. Application of the VEGF gene therapy in sport doping seems
plausible. A larger number of blood vessels in the heart,
lungs or skeletal muscles would enhance blood and oxygen supply to athletes’ tissues, thus improving their effi
ciency and exercise performance.
In 1998, Baumgartner et al. [41] transferred “naked”
plasmid DNA encoding VEGF into the lower-extremity
muscles of PAOD patients. In a few cases the therapy led
to improvement of arterial blood pressure and flow in the
bad limbs and sped up ulcers healing. The side effects
included only transient lower-extremity edema connected with VEGF-related increase in vascular permeability.
In the same year Losordo et al. [42] used as sole therapy a myocardial transfer of “naked” plasmid DNA en
coding VEGF via minimally invasive chest wall incision
in patients with severe CAD. The researchers managed
to alleviate the symptoms of angina pectoris and improve
myocardial perfusion in all the patients. No serious side
effects or life threatening situations were observed.
Another study of the same group of patients [43]
proved a myocardial transfer of “naked” plasmid DNA
encoding VEGF via femoral artery catherization safe.
Such an application may likely allow targeted administration of a vector with VEGF, non-use of general
anesthesia as well as shorter hospitalization of a patient.
The results of some studies on the VEGF transfer
must, however, be treated with caution. In studies on
mice, myocardial delivery of myoblasts showing, thanks
to the presence of retroviral promoter, an uncontrollable
and continuous expression of VEGF, led to a failure to
thrive and formation of endothelial cell-derived intramural vascular tumors [44]. This shows that regulation
of VEGF expression administered as a way of therapeutic
angiogenesis is necessary. Weisz et al. [45] showed, on
the other hand, some potential benefits of a local transfer
108
of VEGF as compared with administration of the VEGF
active protein. An ex vivo transfer of AAV-VEGF to
human endothelial cells resulted in sustaining high
local concentration of this factor and in sensitization of
endothelial cells to VEGF activity.
In a study carried out in Finland VEGF-D was
declared the strongest angiogenic effector among the
VEGFs delivered into rabbit skeletal muscle via adenoviruses [46]. An adenoviral catheter-mediated transfer
of VEGF-D into porcine heart enhanced angiogenesis
and improved myocardial perfusion, so it might be of
therapeutic use [47].
Unfortunately, other studies failed to confirm the
therapeutic properties of VEGF transfer. In the study by
Rajagopalan et al. [48] intramuscular adenoviral VEGF
did not improve exercise performance and quality of life
in patients with peripheral arterial disease.
Nevertheless, it can be assumed that VEGF gene
therapy developed solely for therapeutic use may find
its application in sports doping after the aforementioned
difficulties have been overcome.
Opoids
In the case of numerous terminal diseases, pain poses
a difficult and significant problem. The search for new
methods of alleviating pain has been going on for many
years. The late 1990s witnessed numerous studies on
prospective application of gene therapy for that purpose,
using endorphins. A transient production of Met-encephalin related to pain alleviation after a transfer of human
preproencephalin via the herpes simplex virus vector in
mice was noted [49]. Extensive research has been carried
out in recent years into application of pro-opiomelanocortin (POMC). An intrathecal, electroporation-mediated
transfer of plasmid POMC DNA led to an increase in
concentration of β-endorphins in the spinal medulla and
raising the pain threshold in the rat model of chronic pain
[50]. This may suggest a possibility of application of this
efficient technique in future clinical trials. The same research team in another study (working on the same model)
used an electroporation-mediated, intraspinal delivery
of a system of two plasmids which allowed a doxicline-controlled POMC gene expression. The application of
the system made it possible to regulate production of
β-endorphins, depending on the intensity of pain [51].
Another team showed effective pain alleviation by an
electroporation-mediated transfer of a modified pCMV
plasmid with POMC DNA into the tibialis anterior muscle
in a rat model of rheumatoid arthritis [52].
HUMAN MOVEMENT
Sport has been inseparably linked to pain which may
result from a variety of injuries, overtraining or fatigue.
Permanent pain alleviation, and thus better exercise
performance, can be achieved by application of methods
described above. It requires, however, prior clinical
examinations. By now any prospective application of
POMC in therapy or sport doping seems rather remote.
Insulin-like growth factor-1
IGF-1 is the basic factor contributing to the growth and
regeneration of muscle and other tissues. There have been
studies concerning application of IGF-1 gene therapy in
medical conditions with relative insufficiency of muscle
regeneration processes such as muscular dystrophy and
senescence. The most common type of muscular dystrophy – Duchenne’s dystrophy – features a mutation of
dystrophine – a protein protecting muscle fibers from
damage. In senescence the muscle regeneration processes become inhibited. The insufficiency of protection and
regeneration processes leads to reduction in muscle mass
as well as deprivation of muscle strength and endurance.
IGF-1 causes recruitment of skeletal muscle stem cells
(mainly satellite cells), their differentiation and connection with existing muscle fibers as well as regeneration
of damaged muscle (for a comprehensive description
of muscle stem cells see Chen and Goldhammer [53]).
The greatest contribution to the research on application of TGF-1 gene therapy in treatment of muscular
conditions has been made by H. Lee Sweeney, Elisabeth
R. Barton (-Davis), Antonio Musaro and Nadia Rosenthal,
who worked together a number of times. In 1998, they
discovered that an intramuscular delivery of recombinant
AVV vector with an IGF-1 encoding DNA sequence
blocked the aging-related loss of muscle function [54].
Later they bred transgenic mice in which tissue-specific
expression of local IGF-1 isoform resulted in sustained
hypertrophy and regeneration in senescent skeletal muscle
[55]. They also observed that the transgenic muscle-specific IGF-1 expression exerted a positive effect in
the mouse model of Duchenne’s dystrophy, not only by
contributing to functional hypertrophy but also preventing fibrosis in damaged muscle [56].
Finally, in their most famous study concerning the
role of IGF-1 and IGF-1 gene therapy they showed that
intramuscular administration of IGF-1 encoding AAV
vector in rats enhanced training-related muscle hypertrophy and inhibited the loss of muscle mass following
a stoppage in training [57]. It also turned out that IGF1 enhanced regeneration of skeletal muscle by way of
recruitment of bone marrow progenitor cells [58].
Gene therapy using vectors containing IGF-1 (e.g.
liposomes) can also find its application in sport medicine in healing acute wounds [59]. It is possible that the
achievements in research on IGF-1 gene therapy can be
used in gene doping to enhance and develop selected
muscle groups.
Myostatin
Myostatin belongs to the transforming growth factor-β
group and is a negative regulator of skeletal muscle mass.
It was observed that administration of foliastitin or other
inhibitors of the myostatin signaling pathway resulted in
a considerable increase of muscular mass comparable
with that reached in myostatin null mutant mice. This may
suggest potential application of myostatin inhibitors in
treatment of muscular conditions in humans [60]. The po
tential therapeutic role of the compounds discussed was
further confirmed by crossing of myostatin null mutant
mice with mdx mice (in a mouse model of Duchenne’s
and Becker’s dystrophies). The mdx mice, without the
myostatin gene, featured greater muscular strength and
mass as well as less muscle fibrosis, which was indicative of improved tissue regeneration [61]. Similarly, also
in an mdx model, inhibition of endogenous myostatin
by way of intramuscular delivery of blocking antibodies
brought about an increase in muscle mass and strength
and reduced the intensity of degeneration processes [62].
Application of these encouraging results in dystrophy
treatment requires further research on consequences of
long-lasting inhibition of myostatin and the involved
mechanisms [63]. It also appears that gene therapy techniques linked with the myostatin pathway are very likely
to be developed. If this is the case, their application in
gene doping may become reality.
Other issues
Gene doping has certain “advantages”. Theoretically,
it might be very difficult for some time to detect physiologically regulated natural genetic products in athletes’
bodies. While detection of high Epo and hematocrit levels
may be indicative of using doping, detection of locally
delivered IGF-1 showing tissue-specific gene expression
may be very difficult. It might be possible to detect elements of vectors or substances used that allow genetic
transfer, however, it would require the muscle biopsy in
athletes right before entering competition [2, 4, 12, 15].
Another question connected with gene doping is its
potential harmfulness to health. It includes the threats
linked to the methods of genetic transfer (see “Pros and
109
HUMAN MOVEMENT
cons of gene therapy”) as well as threats related to the
transferred gene, e.g. Epo and VEGF (see “Erythropoietin (Epo)” and “Vascular Endothelial Growth Factor”).
In view of some athletes using the classical doping methods, known for their harmfulness, it does not appear
that the threats connected with gene doping would dis
courage them from using this form of enhancement of
physical capabilities of their own bodies. Finally, ethical
questions, which, however, remain beyond the scope of
the present study, require also a serious consideration.
Conclusions
Rapid development of gene therapy techniques and
specific therapies of certain conditions can lead to an
attempted illegal use of them in sport as a form of gene
doping. A number of experts claim that we may face this
problem very soon.
Acknowledgements
I would like to express my gratitude to Mrs. Agata
Pletnia-Potaczek for drawing the figures for the present
work and to Prof. dr hab. Andrzej Szczeklik and Dr hab.
Marek Sanak for their valuable comments.
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Paper received by the Editors: December 17, 2004.
Paper accepted for publication: May 6, 2005.
Daniel P. Potaczek
II Katedra Chorób Wewnętrznych CMUJ
ul. Skawińska 8
31-066 Kraków, Poland
e-mail: danppot@mp.pl
111
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MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2), 112–115
PUSH-OFF FORCES VS KINEMATICS IN SWIMMING TURNS:
MODEL BASED ESTIMATES OF TIME-DEPENDENT VARIABLES
Jürgen Klauck
Institute of Biomechanics, German Sport University Cologne, Köln, Germany
Abstract
Based on results of force measurements during the push-off phase in swimming an attempt is made to determine the kinematics
of the swimmer’s centre of gravity (C.G.), especially the speed at the end of the push-off phase as an important initial value for
the subsequent gliding phase. This is done by solving approximately the equation of swimmer’s motion; the equation yields the
time dependent speed curve of the swimmer’s C.G. during the whole push-off. The absoute magnitude of the push-off forces and
their distribution over time can be studied in quantitative terms. This information provides some hints with respect to the preferred
training procedures to be followed when pushing-off during the swimming turn.
Key words: swimming turn, push-off force, kinematics modeling
Aims and objectives
After a swimming turn, body speed is generated by
a push-off movement from the pool wall. Evidence suggests that a stronger push-off force, or a greater linear
momentum, delivers more speed to the swimmer. On the
other hand, there are no quantitative data about the relationship between the increase of force (possibly achieved
by training) and greater resultant speed during and after
push-off. Previous literature (e.g. Takahashi et al. [1],
Blanksby et al. [2], Lyttle and Mason [3]) only reported
statistical relations between measured force parameters
and time integral of force with the final speed after push-off. These data show only a tendency for the relations
to be valid for the experimental group of subjects but
cannot be applied to an individual athlete.
In this study, an attempt was made to establish a proce
dure delivering the time curve of speed during the push-off phase by using experimental reaction force time curves
during the push-off. Then, these data were applied to a ma
thematical model (equation of motion), including reasonable settings for the water resistance force. The results
are somewhat speculative, but can provide some insight
into the basic relationship: push-off force vs speed deve
lopment of the moving body based on individual data.
Moreover, force increase/decrease effects on speed can be
studied quantitatively, and the role of the force distribution
over time can be investigated. As a consequence, the re
sults can influence the training process by providing more
effective, individual knowledge of the main influencing factors
one can achieve to give better results in a shorter time.
112
Physical model of push-off:
Properties and consequences
In this section, a mechanical model of the push-off mo
vement of the swimmer’s C.G. is established, discussed
and solved by approximation. Kinematic and dynamogra
phic parameters of the model are valid for the horizontal
direction exclusively. For this direction, the balance of time
dependent external and inertial forces can be given by:
Σ Fext (t) – m ·
dv (t)
= 0
dt
(1)
dv (t)
where dt denotes the time dependent acceleration a(t)
of the swimmer’s mass.
The sum of external forces in equation (1) simply
consists of the reaction force FR (t) due to the swimmer’s
action and the water resistance force Fw (t). It can be
written as:
Σ Fext (t) = FR(t) – Fw(t).(2)
A combination of equations (1) and (2) forms the
equation of motion of the swimmer during push-off:
FR (t) – Fw (t) – m · a(t) = 0.
(3)
In contrast to the push-off force, the water resistance
cannot be measured during the push-off movement. This
means that the differential equation (3) can only be solved
numerically if the parameters (dependent variables) of
the water resistance force are known. The functional
dependence of water resistance on speed and acceleration parameters (because of the non-stationary nature
of the push-off phase) was set in the format as outlined
by Klauck [4]:
HUMAN MOVEMENT
J. Klauck, Push-off forces vs kinematics in swimming turns
Fw (t) = D · v 2 (t) + Δm · a(t)(4)
where: D – constant (resistance factor), and Δm – hydro
dynamically active “additive” mass. Thus one can derive
the complete form of the swimmer’s C.G. differential
equation as:
FR (t) = D · v 2 (t) – [Δm + m] ·
dv (t)
.(5)
dt
This rearranged equation (5) gives a clearer insight into
the dependence of the swimmer’s acceleration during
the push-off:
approximation. This is done by solving the differential
equation with force FR remaining piecewise constant as
proposed by Klauck [5]: The push-off force (recorded
experimentally) is cut into “slices” of short duration,
say Δt, with constant values FR during this time interval.
These force values are introduced together with the speed
values v0 at the beginning of the time interval, and the
speed value at the end of the time interval is determined
by using:
FR (t)
· Δm
m + Δm
v(Δt) =
.
D
1 + v0 +
· Δt
m + Δm
v0 +
FR (t)
dv (t)
D
a(t) =
= Δm + m –
· v 2 (t).(6)
dt
Δm + m
a(t) > 0
means
FR (t) > D · v 2 (t)
(7)
for the whole time interval from the beginning to the
end of the push-off. This condition cannot be fulfilled
because the time curve FR (t) begins and ends with zero
values. Therefore, equation (7) contains an important
consequence with respect to the time course of the
push-off force. Absolute maximal possible speed can
only be obtained if the peak force is applied at the end of
the push-off phase. If peak force is applied earlier, there
is a time interval within the push-off time in which the
acceleration is negative and the speed decreases even if
a push-off force continues to be applied till the end of
this phase. This occurs in contrast to push-off phases in
air where every push-off force contribution can increase
speed, and the position of the time mark of maximal
force does not influence the push-off result.
The above-mentioned findings about the push-off
are not restricted to push-off movements from a firm
wall but are valid also for the propulsion generation in
swimming, rowing, canoeing and kayaking by “push-off
“ from the fluid medium.
Physical model of push-off:
Approximative solution
Since the differential equation (6) cannot be solved
exactly because of the presence of time dependent parameters, the time-dependent speed curve using given time
curves of the push-off force should be computed by an
The computed speed value serves as an initial value
for the following time interval. By this procedure, the
time-dependent speed curve is obtained point by point
by application of time-dependent push-off forces in
combination with the water resistance parameter D.
Applications and examples
Equation (8) allows the speed curves to be determined
from experimental data FR(t), D and Δm using commonly
available software (as, for example, Microsoft Excel). In
this section, some quantitative results based on experi
mental data are discussed.
The first example deals with the role of the absolute
magnitude of reaction force generated during the push-off. The input data of the male subject are: m = 80 kg,
Δm = 40 kg, D = 25 kg/m, experimental curve of the
reaction force (see an example in Fig. 3), time increment
Δt = 0.01 s. Linear variation of the push-off force was done
in the range of ± 10 and ± 20% of the experimental curve.
The resulting speed time curves are presented in Figure 1,
3.0
110% Fr
100% Fr
2.5
120% Fr
2.0
speed C.G. [m/s]
From the structure of equation (6) two elementary
conclusions can be drawn at the first glance:
– the increase of speed depends on the push-off force
applied, and
– the increase of speed is limited by the speed-dependent term in combination with the water
resistance coefficient.
The condition of an increasing speed during the push-off phase can be deduced from equation (6):
(8)
80% Fr
1.5
end of push-off
90% Fr
1.0
0.5
0.0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
time [s]
Figure 1. Speed curves of the C.G. simulated
using different levels of push-off force
113
HUMAN MOVEMENT
3.0
final speed C.G. [m/s]
2.8
2.6
r = 0.9995
2.4
2.3
2.0
1.8
900
1000
1100
1200
1300
1400
1500
maximal push-off force [N]
push-off force [N]
Figure 2. Variation of final speed of C.G.
vs change of maximal push-off force
1400
1200
1000
800
600
400
200
0
push-off
glide
speed C.G. [m/s]
0.0
,
0.1
,
0.2
,
0.3
,
0.4
,
0.5
,
0.6
,
0.7
,
0.8
,
0.9
,
1.0
,
2.5
2.0
1.5
final speed:
1.0
0.5
0.0
0.0
0.1
0.2
0.3
0.4
0.5
2.43 m/s at D = 20 kg/m
2.40 m/s at D = 25 kg/m
2.38 m/s at D = 30 kg/m
0.6
0.7
0.8
0.9
1.0
time [s]
Figure 3. Speed development during push-off
for different resistance coefficients
1400
push-off force [N]
1200
1000
reversed
800
normal
600
400
200
0
speed C.G. [m/s]
0.0
0.1
0.2
0.3
0.4
0.5
0.6
2.5
2.0
reversed
1.5
1.0
0.5
normal
final speed:
normal 2.41 m/s
reversed 2.20 m/s
0.0
0.0
0.1
0.2
0.3
0.4
0.5
time [s]
Figure 4. Effect of positioning of push-off force
maximum on speed development
114
0.6
showing considerable changes of the speed at the end
of the push-off phase due to the different force levels.
The time dependent speed curves show considerable
changes in the value at the end of the push-off phase.
The results show a strong correlation between absolute
maximal force and the final speed (see Fig. 2).
These findings stress the importance of executing the
push-off with maximal effort in order to achieve maximal
final speed. Furthermore, this would require that more
attention is directed towards the training of active muscle
groups during the push-off. This is because we get an
increase of push-off speed of about the same percentage
range as the maximal force improvement brought about
by training procedures.
The role of the resistance coefficient D, with respect
to the speed development, was studied by using the
model as a simulation tool. That is, the movement was
performed under the same mass conditions but with the
constant D varying from small (20 kg/m), normal (25
kg/m) to large (30 kg/m). The result of this simulation
is given in Figure 3 together with the push-off force.
It can be seen that the variation of the resistance
coefficient has no great effect on the time course of
the speed nor on the value of the final speed, the latter
changing in the range of 1 percent only. The different D
values show a greater effect only during the subsequent
gliding phase.
The last simulation experiment consisted in handling
the problem of the distribution of push-off force, or mainly, the problem of the position of maximum force during
the whole movement. As pointed out in the theoretical
section, the optimal position of the maximum force is
very close to the end of the push-off phase in order to
avoid phases of negative acceleration of the swimmer’s
C.G. The simulation is performed by comparing the speed development of a “normal” force curve (as shown in
Fig. 3) to a “reversed” force function with the maximum
position close to the beginning of the push-off. The result
of this comparison is presented in Figure 4.
The maximum position of the force at the very begin
ning of the push-off movement leads to the loss of final
speed by about 10 percent as compared with the position
at the end of the push-off. Hence, force training should
not only contain elements to increase the push-off force
but should be focussed on the point of application of the
maximum force, too.
HUMAN MOVEMENT
Conclusions
By the applying an appropriate mechanical model it
is possible to estimate quantitatively the role of different
parameters such as water resistance, additive mass, timedependent push-off force with respect to the speed deve
lopment during the push-off after a swimming turning.
These parameters can be measured individually and
consequences for the training process can be deduced.
References
1. Takahashi G., Yoshida A., Tsubakimoto S., Miyashita M., Propulsive forces generated by swimmers during a turning motion.
In: Hollander A.P., Huijing P., de Groot G. (eds.), Biomechanics
and Medicine in Swimming. 1983, 192–198.
2. Blanksby B.A., Gathercole D.G., Marshall R.N., Force plate
and video analysis of the tumble turn by age-group swimmers. J
Swimming Res, 1996, 11, 40–45.
3. Lyttle A.D., Mason, B., A kinematic and kinetic analysis of the
freestyle and butterfly turns. J Swimming Res, 1997, 12, 7–11.
4. Klauck J., Man’s water resistance in accelerated motion: an
experimental setup of the added mass concept. In: Keskinen K.L.,
Komi P.V., Hollander P. (eds.), Biomechanics and Medicine in
Swimming VIII. 1999, 83–88.
5. Klauck J., Swimming Speed Estimation Based on Forward Dyna
mics Model. In: Chatard J.-C. (ed.), Biomechanics and Medicine
in Swimming IX. 2003, 75–80.
Paper received by Editors: March 22, 2005.
Jürgen Klauck
Institute of Biomechanics
German Sport University Cologne
Carl-Diem-Weg 6
D 50933 Köln, Germany
e-mail: klauck@dshs-koeln.de
115
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2), 116–123
THE EFFECTS OF CHANGES IN THE TIMING OF MUSCLE ACTIVATION
ON JUMP HEIGHT: A SIMULATION STUDY
Przemysław Prokopow1, 2, *, Stefan Szyniszewski3, Krzysztof Pomorski4
Computational Biomechanics Unit, RIKEN, Japan
Graduate School of Science and Engineering, Saitama University, Japan
3
Graduate School of Natural Science and Technology, Florida University, USA
4
Graduate School of Arts and Sciences, Tokyo University, Japan
1
2
Abstract
Purpose. Vertical squat jump performance critically depends on precise muscle control. The control in jump is performed dominantly
in feedforward manner, wherein preprogrammed nerve impulse volleys (muscle activation patterns) are sent by the central nervous
system to excite muscles in specific sequence, time and amplitude. The purpose of present study was to evaluate on a control of
which muscles the most sensitive is vertical jump and what the importance of setting precise muscle activation time is in obtaining
maximal jump height. Basic procedures. Forward dynamics computer simulation of human body was used in the present study.
In order to evaluate the effect of altered muscle coordination, an optimal solution muscle activation time was first found through an
optimization method and then the optimal activation time of muscles was systematically altered by the interval of 0.1 ms in the range
± 50 ms. Main findings. Muscle activation onset time shift amounting to 2–3 ms resulted in a remarkable (over 10%) difference
in jump height. The most sensitive to precise control in vertical jump were: m. soleus, mm. vasti and hamstrings, where m. soleus
was found to be sensitive on earlier activation, whereas mm. vasti and hamstrings were significantly sensitive to later activation.
Jump was not sensitive to changes in activation offset time. Conclusions. Jump height was found to be exceptionally sensitive to
control of individual muscles. It has been confirmed that precise control of individual muscles is essential in achieving maximum
height in vertical jump. Minimal time interval of applied activation time shift to which jump height was sensitive was very small.
Key words: jump, control, muscle, computer, simulation
Introduction
The sensitivity of the human vertical jump to precise
neural control is a noteworthy problem in terms of movement control and sports biomechanics. The considerable
importance of the human vertical jump arises from the
fact that it is a basic and commonly observed daily
motion pattern that is also an essential skill in volleyball,
basketball, vertical jumping and other sport disciplines.
The latest developments in computer simulation techniques made it possible to study the effect of neural control
[1–7] on movement kinematics and kinetics and hence
elucidate muscle coordination principles. In forward dy
namics computer simulation neural control (i.e. muscle
activation pattern) is given as a single input and motion
dynamics is calculated, therefore it is possible to evaluate
quantitatively the extent to which motion dynamics
depends on a given neural control.
Previous forward dynamics studies demonstrated that
the human vertical squat jump is very sensitive to precise
116
timing of muscle action [1–3]. A computer simulation
technique was used previously to investigate which
muscle group is the most sensitive to a shift in onset
time of the muscles [1] and it was found that jump height
depends the most on control of knee extensors, while
plantar flexors are the most sensitive to precise control
(10 ms onset timing shift resulted in more than 10%
decline in jump height). The importance of precise adjustment of muscle activation time was ascertained by
Pandy et al. [2]. Although their work focused mainly on
the description of an optimal control solution for the
squat jump, they also investigated the sensitivity of the
optimal solution to changes in control of mm. vasti and
m. gastrocnemius. It was found that when activation of
mm. vasti was delayed by 10% (percentage of time from
the beginning of the simulation to lift-off; 10% amounted
to 50 ms), coordination was significantly hampered.
They also noted that control of mm. vasti noticeably
altered the motion of individual limb segments. Further
computer simulation study of muscle strengthening [4]
and neuromuscular training [5] showed that precise
muscle control is indispensable in increasing jump height.
Finally, van Soest and Bobbert [3] demonstrated that:
HUMAN MOVEMENT
P. Prokopow, S. Szyniszewski, K. Pomorski, Muscle control in vertical squat jump
(i) the musculoskeletal system is very sensitive to changes
in precise control and that (ii) muscle properties are essential in decreasing the impact of changes in the control of
the movement of the human body. In their study, they made
the analogy between the mechanics of vertical jumping
and an inverted pendulum. In such systems small distur
bances in control tend to amplify in time. Since body
segmental dynamics are very sensitive to precise control,
the authors demonstrated that small differences in joint
angles significantly affect jump achievements.
Previous studies have discussed the general importance of precisely controlled muscle action on jump perfor
mance. However, no research to date has quantitatively
examined control of muscles and which individual mus
cle is the most important for the performance of vertical
jump. The aim of this study was to investigate the effect
of changes in the timing of muscles in vertical jump.
The motivation underlying this study of precise timing
of muscle activation in vertical jump is threefold: (i)
Firstly, increasing precision of muscle control might be
important in improving sport performance [4, 8], therefore it is important for sport specialists to know the effect of
changes in precise muscle control on movement performance. (ii) Precision in muscle control is diminished as
an effect of diseases such as antiorthostaic hypokinesia [9]
and Huntington’s disease [10]. It is important in clinical
applications to know the effect of this diminishing control on movement. (iii) Moreover, precise muscle con
trol is important in neuromuscular electrical stimulation
[11], neuroprosthetic [12, 13] and biorobotic modeling
[14], where researchers seek to imitate the muscle control.
Therefore, it is useful in these applications to know the
precision of the muscle control as well as the effect of
that precision on human movement.
We believe that knowledge of precise muscle control
in complex movements such as jump can be applied
directly to improve motion patterns of the human body,
particularly when affected by disease or in sports. Due to
the plasticity present at various sites of the motor system,
precise muscle control might be increased by training
[15]. One technique to increase the neural precision of
muscle control in complex motor tasks was proposed by
Scaringe, Chen and Ross [16]. That study investigated
kinetic devices (simulators) and the mechanism of performance feedback and it was proposed that that technique
is suitable for improving neural precision in human body.
Methods
Forward dynamics computer simulation of the vertical
squat jump was used in this study. A 3D musculoskeletal
model of the lower extremities was used to simulate unconstrained three-dimensional jump motion. The body was
modeled as nine rigid body segments, with a 20 degree-of-freedom linkage which was free to make and break
contact with ground. The segments (head–arms–trunk
(HAT), right and left upper legs, right and left lower legs,
right and left feet, and right and left toes) were connected
with frictionless joints. Body segmental parameter values,
i.e. length, mass, location of the center of mass of segments, were derived from de Leva [17]. Hip joints were
modeled as universal joints that have three degrees of freedom. Knee joints were modeled as hinge joints. Ankle
joints were modeled as biaxial joints [18]. Metatarsopha
langeal joints were modeled as hinge joints with tilted
axes [19]. Passive elastic joint moments of hip extension/
flexion, hip abduction/adduction, hip internal/external
rotation, knee extension/flexion, and ankle dorsi/plantar
flexion were applied to the musculoskeletal model as
a set of equations reported by Riener and Edrich [20].
A total number of 26 individual musculotendon actuators (Fig. 1) drove the model (m. gluteus maximus,
m. gluteus medius, m. gluteus minimus, m. adductor
longus, m. adductor magnus, hamstrings, m. adductor
brevis, hip external rotators, m. rectus femoris, mm. vasti,
m. gastrocnemius, m. soleus, and other plantarflexors).
These are a Hill-type musculotendon model that consists
of a contractile element and a series elastic element [5].
Muscle parameter values, i.e. optimal contractile element
length, maximal isometric force of contractile element,
and pennation angle, were derived from Friederich and
Brand [21] (Tab. 1). Muscle activation dynamics (i.e.
delay between muscle activation and muscle active state)
was described in the form of first-order differential equa
tion [5]. Each muscle activation pattern was specified by
three variables, i.e. onset time, offset time, and magnitude
of activation [5]. The interaction between the foot segments and the ground was modeled similarly to Anderson
and Pandy [22]. The model was free to make and break
contact with the ground. A complete description of the
musculoskeletal model can be found elsewhere [23].
An optimal control muscle activation pattern of the
squat jump was found through numerical optimization.
As an objective function we used a maximum height
reached by the mass centroid of the body. At the initial
time the body was assumed to be in a static squat position
(Tab. 2) and the activation level of all muscles was set to
zero level (no excitation). Maximum height was obtained
through numerical optimization of activation patterns
where Bremermann’s method of unconstrained opti117
HUMAN MOVEMENT
Table 1. Muscle parameters: maximal isometric force
(FMAX), optimal contractile element length (LCEopt)
and tendon slack length (Lslack)
FMAX (N) LCEopt (m) Lslack (m)
m. gluteus maximus
1883.4
0.1420
0.1250
m. gluteus medius
1966.2
0.0535
0.0780
m. gluteus minimus
848.6
0.0380
0.0510
m. adductor longus
716.0
0.1380
0.1100
m. adductor magnus
1915.8
0.0870
0.0600
m. adductor brevis
531.1
0.1330
0.0200
hip external rotators
1512.0
0.0540
0.0240
m. rectus femoris
1353.2
0.0840
0.4320
hamstrings
3053.6
0.0800
0.3590
mm. vasti
6718.3
0.0870
0.3150
m. gastrocnemius
2044.4
0.0450
0.4080
m. soleus
5880.7
0.0300
0.2680
other plantarflexors
3137.1
0.0310
0.3100
The values of muscles maximal force and optimal contractile element
length were derived from Friederich and Brand [21]. The values of
tendon slack length and muscle geometry were derived from Delp [19].
mization [24] was applied. As the squat jump has been
assumed to be bilaterally symmetric, identical neural
control signals were sent to muscles in both legs.
In order to quantitatively evaluate the importance of
control of individual muscles for jump height we shifted
muscle activation time. Specifically, we altered either
muscle onset time, muscle offset time, or muscle switching
time (total activation duration remained constant but
onset and offset times were shifted equally). In every trial,
after applying a new activation pattern, the jump motion
was re-evaluated. The range of applied time shift was
± 50 ms and the resolution of the shift was 0.1 ms. Each
of the muscles used in the simulation was examined
separately. Only 16 out of 26 muscles were investigated
as the remaining 10 muscles were found to be silent in
squat jump (activation magnitude ~0%).
Results
The numerical optimization procedure generated a
natural-looking and smooth squat jumping motion. The
optimal jump motion generated in this study is depicted
in Figure 2. The simulation resulted in a jump height of
34.57 cm. The angular displacement of each joint has
been plotted in Figure 3. Muscle optimal activation timing
is presented in Figure 4. A magnitude of stimulation had
a range zero (no excitation) to one (muscle fully excited),
118
Table 2. The starting position in the simulated squat jump
Joint
Hip flexion
Position (deg)
86.7
Hip abduction
0.0
Hip internal rotation
0.0
Knee flexion
80.3
Ankle dorsi flexion
28.5
Ankle aversion
0.0
Metatarsophalangeal joint dorsi flexion
0.0
The values of these parameters were adapted from Anderson and
Pandy [22], who carried out experiments to measure the initial position
in a squat jump and then they were optimized in order to fit to the model
[23]. The values are given for only the right side of the body as the
position of left leg was assumed to be the same as for the right leg.
where virtually any value in that range could be chosen
as a result of optimization process. In fact, however, optimization resulted in bang-bang control, where muscles
were chosen to be either fully exited or not excited at all.
The active muscles in the simulation were: m. gluteus
maximus, m. adductor magnus, hamstrings, m. rectus
femoris, mm. vasti, m. gastrocnemius, m. soleus and
other plantarflexors. The optimal squat jump solution
presented in Figures 2 to 4 is consistent with previous
studies [2, 5–7, 22].
Muscle control in a vertical jump was exceptionally
sensitive to a shift applied to onset time. Jump control
was sensitive to shifts in muscle activation onset time
amounting to less than 2–3 ms. The effect of activation
time shift applied to each of the individual muscles on
jump achievement is presented in Figures 5a–h.
Control of the squat jump deteriorated the most by
earlier activation of monoarticular ankle plantarflexor
(m. soleus; Fig. 5g) and delayed activation of monoarticular knee extensor (mm. vasti; Fig. 5e). Control of
plantarflexors (m. soleus, m. gastrocnemius and other
plantarflexors) and control of the muscles spanning the
hip joint (m. gluteus maximus, m. adductor magnus,
hamstrings, m. rectus femoris) were sensitive to earlier
activation. Control of the biarticular muscles was dominated by control of the hamstrings (Fig. 5d).
Control of muscles with larger isometric maximum
force: mm. vasti, m. soleus, hamstrings and other plantarflexors (Tab. 1) was found to be especially important
for muscle control in jumping.
Muscles control was not equally sensitive to earlier and
delayed activation onset timing. The most sensitive to
HUMAN MOVEMENT
Figure 1. Schematic drawing of the 3D musculoskeletal
model of the lower extremity in the sagittal plane consisting
of 9 body segments and 26 major muscle groups.
Each muscle is modeled in series with tendon. Muscles
used in the vertical squat jump simulation include:
GMAX (m. gluteus maximus), HAMS (hamstrings),
RECT (m. rectus femoris), VAST (mm. vasti), GAST
(m. gastrocnemius), OPFL (other plantarflexors),
and SOLE (m. soleus), (m. adductor magnus is not shown
but is also used in the simulation)
Figure 2. Optimal control of vertical squat jump motion
generated in this study. All diagrams are equally spaced
in time (Δt = 0.03 s). The motion pattern found through
a numerical optimization method resulted in smooth movement consistent with previously published
experimental data. The three-dimensional kinematics generated in the study was bilaterally symmetrical
a later activation were mm. vasti (Fig. 5e) and the hamstrings (Fig. 5d), whereas m. soleus (Fig. 5g) and other
plantarflexors (Fig. 5h) were found to be considerably
sensitive to earlier activation. Other examined muscles:
m. gluteus maximus (Fig. 5a), m. gluteus medius (Fig.
5b), m. rectus femoris (Fig. 5c), and m. gastrocnemius
(Fig. 5f) were sensitive to earlier activation.
Among examined muscles: m. adductor magnus
(Fig. 5b), hamstrings (Fig. 5d), mm. vasti (Fig. 5e), and
other plantarflexors (Fig. 5h) were found to be sensitive
to both, earlier and delayed activation, whereas muscles:
m. gluteus maximus (Fig. 5a), m. rectus femoris (Fig.
5c), m. gastrocnemius (Fig. 5f) and m. soleus (Fig. 5g)
were a little sensitive to activation delay.
Muscle control in the squat jump was found to be
insensitive to a time shift applied to activation offset
time. In particular, further prolongation of the activation
time of m. gluteus maximus, m. adductor magnus, m.
rectus femoris, mm. vasti, m. gastrocnemius, m. soleus,
and other plantarflexors until lift-off was found to have
a negligible effect on jump height (decline less than 0.1
cm). On the other hand, prolonging activation of the
hamstrings was found to have a minor effect on overall
jumping performance and kinematics. In this case, the
jump height decreased by 0.6 cm. Resulting rotational kinematics differed slightly from the optimal control jump
(maximal difference in joint angles amounted to 2 deg).
Discussion
The present study investigates the importance of the
control of individual muscles in vertical jumping. It was
found that the most sensitive to activation timing are
three muscles: mm. vasti, hamstrings and m. soleus. In
addition, the control of m. soleus was found to be especially sensitive to earlier activation, while muscles: mm.
vasti and the hamstrings were found to be the most sensitive to later activation. This finding is consistent with
a previous study by Bobbert and Zandwijk [1] wherein
the authors demonstrated that jump height is particularly
sensitive to the onset time delay of plantarflexors relative
to the onset time of the proximal muscles. Furthermore
the finding that mm. vasti is sensitive to later activation is
consistent with the previous work of Pandy et al. [2]. One
important finding obtained in this study is that individual
muscles are not equally sensitive to premature activation
and activation delay. It was found that control of monoarticular muscles spanning the hip and ankle joints
(m. gluteus maximus, m. adductor magnus, m. soleus and
other plantarflexors) was sensitive to earlier activation,
119
HUMAN MOVEMENT
Figure 3. Mean time histories of hip ( ), knee ( ), ankle ( ), and subtalar ( ) joint angles during the ground contact phase
of jumping. Time t = 0 marks the instant of toe-off. The push-off phase began shortly (~0.1 s) after beginning
of the simulation
Figure 4. Optimal muscle stimulation pattern, found through
numerical optimization. Time is expressed relative to take-off
with simulation time starting at 400 ms before take-off.
Abbreviations of muscle names are the same as in Figure 1
while control of the monoarticular knee extensor (mm.
vasti) was sensitive to activation delay. Control of the
biarticular hamstrings was sensitive to later activation,
while timing of m. rectus femoris and m. gastrocnemius
was sensitive to earlier activation. None of the previous studies of vertical jump movement investigated the
sensitivity of control to muscle offset timing. This study
has demonstrated that jump coordination is insensitive
(with the exception of the biarticular hamstrings that was
found to have a minor effect) to changes in activation
120
offset time. This finding might be explained by previous
results [7], which demonstrate that muscle contribution to the vertical acceleration of the body center of
gravity near take-off is negligible at which time most
of the acceleration is produced by body segment inertia.
Even if muscles are activated longer than in the optimal
solution, they can produce only relatively small forces
in the extended activation time. This is because the muscles have already been shortened (force–length muscle
property determines that the shorter the muscle length
is over its optimal length the less force the muscle can
generate) and the contraction velocity is relatively high
(force–velocity muscle property determines that at high
muscle velocity muscle force is small). In such conditions
muscles cannot produce significant forces and therefore
are not capable of causing further increase in the body
segments inertias. Therefore, the control of muscles
near take-off has a negligible effect on jump kinetics
and jump height.
The conclusions of the present study were drawn with
an assumption that the control in squat jump is done in
a complete feedforward manner. This seems to be valid
in vertical jump motion [1, 3] as the push-off phase takes
a very short time (~300 ms; Bobbert, Huijing, and Ingen
Schenau [25]) compared to the time required by the fastest
possible feedback mechanism (fastest short latency
reflex is known to take 40 ms [26], while an additional
of 50–100 ms [27] is needed for the muscle to react to
a reflex output).
HUMAN MOVEMENT
34.6
m. gluteus maximus
25.9
17.3
8.6
a)
0
–50
34.6
c)
25
b)
50
34.6
m. rectus femoris
25.9
17.3
17.3
8.6
8.6
0
hamstrings
0
–50
–25
0
25
50
–50
34.6
mm. vasti
25.9
25.9
17.3
17.3
8.6
8.6
0
–25
0
25
50
0
25
50
d)
0
25
50
f)
0
25
50
h)
m. gastrocnemius
–50
–25
34.6
m. soleus
other plantarflexors
25.9
25.9
17.3
17.3
8.6
8.6
0
–50
–25
0
–50
34.6
g)
0
25.9
34.6
e)
–25
0
–25
0
25
50
–50
–25
Figure 5. The effect of time shift applied to optimal muscle activation onset time of each individual muscle
on jump achievements. Applied time shift resolution amounted to 0.1 ms
121
HUMAN MOVEMENT
The results presented in the paper were generated
by a biomechanical model and simulation approach.
Regrettably, it is impossible to confirm our findings by
direct experiments in vivo. However, the usefulness and
reliability of a forward dynamics approach has been examined and was confirmed by a number of studies (e.g.
Bobbert and van Soest [4], Bobbert and van Schenau [6],
Pandy and Zajac [7]). The reliability of the optimal squat
jump solution used in the present study was confirmed
by a quantitative comparison with the experimental data
presented in the above literature and it was found that
the present model represents all the features salient for
human vertical jumping. Compared to other forward
dynamics studies, our whole-body model was three dimensional and was free to make and break contact with
the ground. This convinces us that the present simulation
was able to accurately reconstruct the effect of altered
muscle control on squat jump performance.
The finding of this paper is that jump motion is very
sensitive to changes in precise muscle timing (2–3 ms),
which is consistent with the previous work of Hore et
al. [28], who investigated the precise timing of finger
opening in overarm throws and demonstrated that the
precision with which ball is released for long throws is
less than 1 ms.
The results in this study indicate exceptionally high
sensitivity of jump performance to changes in precise
muscle control and remains in agreement with previous
investigations, which studied the precise timing required
in muscle activation and release for fast accurate throws
[29]. These investigations demonstrated that the window
during which the wrist flexors could be activated in
human throwing was 10 ms.
On the other hand, the variation in the timing of
muscles EMG-patterns of subjects performing jumps
repeatedly is much greater than that found in our study
[1]. This can be explained by (i) the fact that in humans
there are many control patterns which lead to suboptimal
jump. The control pattern will definitely change with the
starting position of the foot on the ground and other factors
that make it, in practice, impossible to generate two
identical movement patterns in vivo. (ii) The forward
dynamics simulation used in this study, even though complex but verified, certainly did not include all stabilizing
features present in vivo and mechanically remains much
simpler than actual human motion patterns. Hence, the
sensitivity of the model is expected to be higher than
in actual human motion patterns. Furthermore, the data
collected by the EMG might be classified qualitatively
122
rather than quantitatively because it is difficult to precisely
define the timing of muscle stimulation. Therefore, we
suggested that differences in timing of muscle stimulation measured by EMG [1] might be greater than it
actually is in the human body.
Conclusions
The present modeling approach has demonstrated
a high sensitivity of muscles to control (i.e. precisely set
activation time). It was found that changing the activation
onset time of certain muscles (i.e. mm. vasti, m. soleus
and hamstrings) by as little as 2–3 ms resulted in a
remarkable (over 10%) difference in jump height. This
is an extremely short amount of time when considering
that the electromechanical delay in surface EMG ranges
between 20 and 100 ms.
Appendix
The activation-excitation dynamics was adapted from
Nagano [5] and was described in the model as the first-order
differential equation:
α–q
q=
,
(τrise – τdecl) · α + τdecl
where the values of τrise = 55 ms (ascending time constant) and
τdecl = 65 ms (descending time constant) were adapted from
Nagano [23].
The formula for the muscle force produced during isometric
contraction was adopted from van Soest and Bobbert [3] and
from Cole et al. [30]. The fraction of the force relative to ma
ximal muscle force is given by the equation:
Fisom = c1
LCE
LCE 2
+ c2 ·
+ c3,
LCEopt
LCEopt
where
c1 = –1.0 2 ,
width
c2 = –2.0 · c1,
c3 = 1.0 + c1.
The value of width = 55% (maximum length range of
active force production relative to LCEopt) was derived from
Allinger et al. [31].
The equation describing the force–velocity relation was
adopted from van Soest and Bobbert [3]. The following equa
tion describes the force–velocity relation for concentric phase:
VCE = –FACTOR · LCEopt
(Fisom + AREL) · BREL
– BREL ,
LCE + A
REL
FMAX · q
were FACTOR = min(1, 3.33 · q) and the values of Hill’s
constants AREL = 0.41 and BREL = 5.2 was derived from van
Soest and Bobbert [3].
HUMAN MOVEMENT
The force–velocity relation for eccentric was derived from
van Soest an Bobbert [3] and from Cole et al. [30]:
VCE = –LCEopt
c1
,
FCE + c
2
FMAX · q
in which
c2 = –Fisom · Fasympt ,
c1 =
FACTOR · BBEL · (Fisom + c2)2
,
(Fisom + AREL) · slopefactor
c1
c3 = F · c ,
isom
2
where the value of slopefactor = 2.0 (the ratio between derivatives dFCE/dVCE), Fasympt = 1.5 (the asymptotic maximal force
relative to FMAX in the eccentric phase) was derived from van
Soest and Bobbert [3].
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Paper was received by the Editors: March 2, 2005.
Paper accepted for publication: July 11, 2005.
Przemysław Prokopow, M.Sc. Eng.
Computational Biomechanics
The Institute of Physical and Chemical Research, RIKEN
2-1, Hirosawa, Wako, Saitama 351-0198, Japan
e-mail: przem@riken.jp
123
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HUMAN
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2005, vol. 6 (2), 124–128
SELECTED ASPECTS OF MOTOR COORDINATION
IN YOUNG BASKETBALL PLAYERS
Teresa Zwierko*, Piotr Lesiakowski, Beata Florkiewicz
Institute of Physical Culture, University of Szczecin, Poland
Abstract
Purpose. The aim of the study was to assess selected motor coordination aspects in young basketball players as compared with
their non-sporting counterparts; the study also served as an evaluation of recruitment criteria and initial training stages. Basic
procedures. The study involved forty 14–15-year-old skilled basketball players from four macroregions in Poland. The control
group consisted of 40 non-sporting boys of the same age. Computer-assisted laboratory technology was used to measure the following abilities: time of simple reaction to visual stimuli, spatial orientation, complex multiple-stimuli reaction and focused attention, frequency
of movements, dynamic-spatial differentiation, directional and temporal anticipation and rate of movement acquisition. Main findings.
Highly significant differences (p < 0.01) between the skilled basketball players and the non-sporting subjects were observed in the
spatial orientation, complex reaction and focused attention, and the rate of movement acquisition tests. Differences in frequency
of movements, spatial and temporal differentiation and temporal anticipation were also significant, but at p < 0.05. Conclusions.
Young basketball players, due to the well-selected recruitment criteria and training routine displayed a significantly higher level of
selected motor coordination abilities as compared with their non-sporting counterparts. The results of the study show that the selected
aspects of motor coordination are crucial during the recruitment of young players; the assessment of spatial orientation, complex
reaction and focused attention as well as the movement acquisition rate could be especially helpful in selection of prospective players.
Key words: basketball, coordination, young players
Introduction
Basketball is one of the most demanding sports from
the standpoint of coordination training [1–3]. Studies
have shown that results of coordination motor tests have
a direct and significant influence on the performance level
of basketball players, especially younger ones. Dembiń
ski [4] examined factors that exerted the greatest impact
on the effectiveness of performance in basketball. He
observed that motor coordination, effective free throws
and shots on run had a great influence on young basketball players’ overall effectiveness (D = 23%). On the
other hand, Kubaszczyk [5], in his study of correlations
between the level of motor coordination skills and special
competence in 171 young basketball players (13–18 years
old), observed that motor coordination skills and technical
skills were an integral and essential constituent part of
the players’ competence structure.
The effect of highly complex exercises on the level of
technical preparation in young female basketball players
was studied by Mikołajec and Ryguła [6]. During their two-year-long research a correlation was observed between
124
coordination skills (spatial orientation, kinesthetic diffe
rentiation, reaction time, balance) and individual technical skills (throwing effectiveness, dribbling speed, shot on
dribble effectiveness, time and effectiveness of two-hand
chest passes). In the younger group (13–14 years of age)
out of 96 analyzed coefficients of correlation 50 turned
out to be significant; in the older group (17–18 years of age)
39 out of 120 correlation coefficients were significant.
Different studies on conditions of basketball players’
skills also focused on more elementary psychomotor func
tions constituting the basis of motor coordination skills.
Kioumourtzoglou et al. [7], by using laboratory mea
suring methods, studied cognitive factors (memorizing abi
lities, perceptual skills and speed, anticipation, selective
attention) and coordination skills (dynamic balance, body
coordination, dexterity, rhythmicity) in a group of highly
skilled basketball players (n = 13) as compared with
a group of physical education students. The studied group
of basketball players under study displayed a higher level
of dexterity, but a lower level of dynamic balance. More
over, the basketball players achieved higher results in the
memorization, anticipation and selective attention tests.
The present study attempted to objectively evaluate the
motor coordination sphere in young basketball players,
using computer-assisted laboratory technology. Selected
aspects of motor coordination in players aged 14–15 years
HUMAN MOVEMENT
T. Zwierko, P. Lesiakowski, B. Florkiewicz, Selected aspects of motor coordination
were assessed and compared with the results achieved
by their non-sporting counterparts. The study attempted
to evaluate the effectiveness of the basketball players’
preliminary recruitment and initial training stages.
The study group consisted of 40 basketball players,
aged 14 and 15 years, representing four macroregions
in Poland. The study was carried out between June 26
and July 5, 2004, during a training camp of the Polish na
tional junior basketball team in Szczecin. The subjects’
mean body height was 188.30 ± 7.63 cm, and the average
body weight amounted to 74.70 ± 8.7 kg. The subjects’
average sports training period was 4.56 ± 0.68 years.
The control group consisted of 40 non-sporting boys,
aged 14–15 years, from the 25th Junior High School in
Szczecin. The average body height in the control group
was 175.07 ± 7.90 cm; the average body weight 60.13
± 9.56 kg.
The study used computer-assisted measuring methods. The following abilities were assessed:
– Simple reaction time. The “cancel the circle” test
included in the “Motoryk” Software Package was used [8].
The subjects were supposed to press a key as soon as
a circle appeared on the computer screen. The test was
repeated 15 times. The reaction times were from 0.5 to
4.0 s. After the tests had been completed the average
reaction time was calculated.
– Temporal-spatial orientation. The “marking numbers” test included in the “Motoryk” Software Package
was used [8]. The subjects were to arrange a designated
space by mouse-clicking on 16 numbered circles of various sizes that appeared on the computer screen. The
mean reaction time was then calculated.
– Complex reaction and focused attention. The decision test included in the Wiener Test System (Schuhfried,
Austria) was used. The subjects were to react to visual
stimuli (in white, yellow, red, green and blue colors)
and auditory stimuli (high pitch and low pitch sounds),
by pressing five buttons with the right or the left hand
corresponding to five color lights. White lights which
appeared on a black background required pressing one of
two pedals with a foot. The subjects reacted to the emitted sounds by pressing a respective key with one or two
hands. Subjects’ correct responses (n) were analyzed.
– Frequency of movements. The bimanual tapping test
included in the Wiener Test System (Schuhfried, Austria)
was used. The subjects were tapping a plane composed
of squares 40 × 40 mm with a pen within 32 s.
– Dynamic-spatial differentiation. A test consisting
in aiming at points included in the Wiener Test System
(Schuhfried, Austria) was used. The subjects’ task was
to touch 20 lined circles (sensors) on the panel of the
measuring device with a pen held in the dominant hand.
The number of correct hits (n) and total time (s) were
calculated.
– Directional anticipation. The anticipation of direction test [9] was used. A dot (p) appeared at the top of
the screen and moved towards one of three target points
(c1, c2, c3) at the bottom of the screen. The subjects
were to determine the direction of movement of the dot by
pressing a respective key. The test consisted of 40 trials.
The subjects were to anticipate the direction of the dot
moving with the speed of V = 0.17 m/s, V = 0.33 m/s,
V = 0.42 m/s, and V = 0.59 m/s, respectively.
– Temporal anticipation. The time anticipation test
was used [9]. Two-thirds of the length of the route of the
moving dot on the screen was not shown to the subject.
The subjects were to anticipate the time in which the dot
would reach one of the target points. The test consisted
of 40 trials with the dot moving with an increasing
speed (V = 0.17 m/s, V = 0.33 m/s, V = 0.42 m/s, V =
= 0.59 m/s). The mean time difference (s) between the
actual and anticipated time of reaching the target was
measured by pressing the key “Reaching Target”.
– Rate of movement acquisition. The motor abilities
test was used [10]. The subjects were shown a footage
including a sequence of movements and were to re-create
it. If a subject repeated the sequence in a wrong order he
was shown the footage once again. The number of trials
(n) needed to re-create the sequence of movements in
the correct order was calculated.
Results
The examination of basic somatic parameters of the
boys under study revealed a statistically significant (p <
< 0.01) difference in the body height in both the study
and control groups. The mean body height in the study
group was 13.23 cm bigger than the average body height
in the control group.
Table 1 presents statistical characteristics of the para
meters being studied in the basketball players’ group and
the control group. The results of the motor coordination
tests indicate a considerable diversification within each
group. It can be confirmed by relatively high values of
the coefficients of variability in both groups. In the study
group the greatest diversification was observed in the
results of the temporal anticipation test (V = 38.29%)
125
HUMAN MOVEMENT
Table 1. Statistical analysis of test results in two groups being studied
Ability (test)
Simple reaction time
(cancel the circle) (s)
Spatial orientation
(marking numbers) (s)
Complex reaction and focused
attention (decision test) (n)
Frequency of movements
(bimanual tapping test) (n)
Dynamic-spatial differentiation
(aiming at points) (n)
Dynamic-spatial differentiation
(aiming at points) (s)
Directional anticipation
(anticipation direction test) (s)
Temporal anticipation
(time anticipation test) (s)
Rate of movement acquisition
(motor abilities test) (n)
Basketball players group
x
SD
V (%)
x
Control group
SD
V (%)
Difference
|d|
0.276
0.036
13.04
0.279
0.037
13.26
0.003
29.341
5.693
9.402
33.641
6.525
19.396
4.300**
237.615
25.615
10.780
213.259 25.080
11.760
24.356**
371.769
41.665
11.20
343.480 54.660
5.913
28.289*
9.692
2.237
23.080
7.640
3.925
51.374
2.052*
7.351
1.328
18.065
7.668
1.606
20.944
0.317
0.406
0.051
12.560
0.424
0.049
11.556
0.018
0.141
0.054
38.297
0.178
0.099
55.617
0.037*
4.675
1.508
32.256
8.740
3.747
42.871
4.065**
* p < 0.05, ** p < 0.01
and the rate of movement acquisition test (V = 32.25%).
In the control group the most diversified were the results
of the dynamic-spatial differentiation test (V = 51.37%),
and in the players’ group temporal anticipation (V =
55.61%) and rate of movement acquisition (V = 42.87%).
Table 1 also shows the arithmetic mean values of
the results of particular tests in the two groups. It can
be concluded that the mean value of the simple reaction
time test is only 0.003 s better in the players’ group than
in the control group. The difference is not, however,
statistically significant.
A highly significant difference ( p < 0.01) was noted
between the results of the spatial orientation test. The
study group was 4.300 s better than the control group
(1.5 SD). Similar results can be seen in the complex
reaction and focused attention test. The arithmetic mean
in the study group was 237.615 ± 25.615 correct responses, whereas in the control group 213.259 ± 25.080 correct
responses. The difference was 24.356 and statistically
significant ( p < 0.01).
In measurement of the frequency of movements the
bimanual tapping test was applied. The mean results were
28.289 hits more in the study group. The difference was
statistically significant ( p < 0.05).
In the dynamic-spatial differentiation test two variables were measured: number of hits and reaction time.
126
The results were better in the players’ group. A statistically
significant difference (p < 0.05) was only observed in
the case of successful hits (d = 2.052).
In the anticipation tests a statistically significant
difference was only observed in the case of temporal
anticipation ( p < 0.05). The arithmetic mean in the basketball players’ group amounted to 0.141 ± 0.054s and
was 0.037s better than the arithmetic value in the control
group. In the directional anticipation test the players’
group achieved better mean results (xx = 0.406 ± 0.051s)
than the control groupx (x = 0.424 ± 0.049s), but the
difference (d = 0.018s) was not statistically significant.
A highly significant difference ( p < 0.01) was noticed between the arithmetic mean results of the rate of
movement acquisition test (motor abilities test) in the
two groups. The mean results in the players’xgroup (x
= 4.675 ± 1.508) were 4.065 better than in the control
x
group x = 8.740 ± 3.747.
Discussion
The tests used in the present study made it possible to
thoroughly evaluate selected aspects of motor coordina
tion in young basketball players as compared with their
non-sporting counterparts.
Obviously, the groups under study differed from each
other in terms of somatic parameters: body height and body
HUMAN MOVEMENT
0.6
0,6
0,5
0.5
0,4
0.4
0.3
0,3
0,2
0.2
rate of movement
acquisition
szybkoœæ uczenia siê ruchów
antycypacja
czasu
temporal
anticipation
antycypacja
kierunku
directional
anticipation
dynamic-spatial
przestrzenne
differentiation
ró¿nicowanie dynamiczno-
of movements
frequency
czêstotliwoœæ
ruchów
reakcja z³o¿ona i skupienie
complex reaction
uwagi
and focused
attention
orientacja
przestrzenna
spatial orientation
00
szybkoœæreaction
reakcji prostej
simple
time
0,1
0.1
Figure 1. Characteristics of selected motor coordination
aspects in basketball players (normalized values)
weight ( p < 0.01). This proves that those parameters were
taken into consideration during the recruitment of basket
ball players, which seems to be quite appropriate, consider
ing specific morphological requirements in basketball.
After the evaluation of the motor coordination aspects
a profile of basketball players’ abilities was drawn in
reference to the control group (Fig. 1).
In most of the variables examined the basketball
players achieved higher results than their non-sporting
counterparts. Statistically significant differences were
observed in spatial orientation (p < 0.01) and dynamic-spatial differentiation (variable: number of hits, p <
0.05). These abilities are regarded as most essential in
the development of basketball skills [11, 12]. An expert
analysis carried out by Ljach [13] made it possible to
create a hierarchy of basic coordination abilities necessary
in basketball. These include spatial orientation, matching,
speedy reaction, movement linkage, rhythmicity and
balance. The results of the present research confined to
laboratory measurements seem to confirm in part the
above conclusions, however, the results of the simple
reaction time test are not different (d = 0.003s).
The basketball players group achieved higher scores in
their complex reaction and focused attention test ( p < 0.01).
In this case, the test results translate directly into the
specificity of motor actions performed during any bas
ketball game. The dynamics of play and constantly changing situations during a basketball match require prompt
commencement and execution of effective movements
from the players in response to signals from their teammates and opponents, or reacting to the moving ball [12].
Perceptual abilities (especially recognition of visual sig
nals) contribute significantly to the effectiveness of players’
actions. Al-Abood et al. [14] in their study of effects of
visual perception and verbal instructions on the effec
tiveness of free throw shooting in beginning players
observed that the skill with the greatest impact on the
accuracy of free throw shots was focusing attention during
the final stages of movement (e.g. ball trajectory). Cesari et al. [15] noted a significant correlation between
basketball players’ sports level (n = 30), their motor
system activity and their abilities to recognize and anticipate the effects of shots seen on a television screen.
The results of the present research show that the
players achieve higher scores in anticipation tests. A sta
tistically significant difference ( p < 0.05) between the
studied groups was noted in the results of the temporal
anticipation test. The results confirm to some extent the
results of a comparative analysis (using the same evalua
tion method) conducted by Zwierko et al. [16] on team
games players (n = 22) and individual sports players
(n = 18). The team games players achieved higher results
in the temporal and directional anticipation tests ( p < 0.05).
It can be stated that the specificity of training in team
sports determines a higher level of motor anticipation
in players. The wider the spectrum of objects involved
in a given motor situation and the shorter the time to the
anticipated occurrence, the higher the expectations for
anticipation abilities [17]. Team games often feature
situations in which the time of the ball flight is shorter
than the player’s reaction and motor response time,
whereas the speed of action often requires the players
to make various anticipatory decisions on the pitch [18].
Statistically significant differences between the groups
under study were also observed in movement frequency,
measured with a bimanual tapping test. The tapping test
is considered one of the best measuring methods to reflect
the capability of the central nervous system and its effec
tors. Especially bimanual tapping (also used in the present
research) is tremendously useful in diagnosis of quality
and effectiveness of motor control as it requires coordination of work with the maximum speed of two limbs
[19]. The results of the present study may indicate that
the level of movement frequency in the basketball players
group translates directly into the players’ high level of
coordination preparation.
Highly statistically significant differences ( p < 0.01)
were also noted in the group of basketball players in the
movement acquisition rate measured with the motor
abilities test [10]. The research results confirm a significant influence of motor abilities on the sports level in
young players [20–22].
127
HUMAN MOVEMENT
The results of the study of the selected aspects of
motor coordination in highly skilled basketball players
aged 14–15 years confirm the role of motor coordination
in this sport. They may serve as useful hints in developing
recruitment criteria in basketball.
Conclusions
Young basketball players, due to well-directed recruitment, selection and training, represent a significantly
higher level of motor coordination aspects as compared
with their non-sporting counterparts. The greatest differences in results achieved by the two studied groups were
observed in the spatial orientation, complex reaction and
focused attention and rate of movement acquisition tests.
References
1.Glasauer G.J., Nieber L., Theoretical basis for coordination training
in basketball [in German]. Leistungssport, 2000, 30, 28–37.
2.Nevill M., Intermittent exercise testing for games players. In:
Avela J., European College of Sport Science. July 19–23 2000,
Jyvaskyla, 7.
3.Ljach W., Selected aspects of coordination training in a long-team
system of preparation of basketball players. Education. Physical
Training. Sport, 2002, I 42, 34–43.
4.Dembiński J., Effectiveness of performance in basketball training
[in Polish]. Trening, 1997, 3, 124–134.
5.Kubaszczyk A., Motor coordination level and special competence
in basketball [in Polish]. Wych Fiz i Sport, 2001, 4, 481–499.
6.Mikołajec K., Ryguła I., The effect of highly complex exercises
on the special competence level and technical and tactical effectiveness of young basketball players [in Polish]. Trening, 1999,
1, 39–67.
7. Kioumourtzoglou E., Derri V., Tzetzis G., Theodorakis Y., Cog
nitive, perceptual, and motor abilities in skilled basketball perfor
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8.Juras G., Waśkiewicz Z., Time, space and dynamic aspects of
coordinational motor abilities [in Polish]. AWF, Katowice 1998.
9.Konzag G., Krug Th., Lau A., Objectivation of players’ anticipation capacities [In German]. Theorie und Praxis der Körperkultur,
1988, 37 (3), 188–194.
10.Szopa J., Latinek K., Studies on the essence and structure of
motor coordination abilities [in Polish]. Antropomotoryka, 1998,
17, 43–61.
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11. Brill M.S., Selection in sport games [in Russian]. FiS, Moskwa
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12.Raczek J., Mynarski W., Ljach W., Shaping and diagnosing motor
coordination abilities [in Polish]. AWF, Katowice 2002.
13.Ljach W., Coordinational preparation in team games [in Polish].
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Podlaska 1995, 155–167.
14.Al Abood S.A., Bennett S.J., Hernandez F.M., Ashford D., Davids
K., Effect of verbal instructions and image size on visual search
strategies in basketball free throw shooting. J Sports Sci, 2002,
20, 271–278.
15.Cesari P., Romani M., Aglioti S., Movement recognition and mo
vement execution: knowing and knowing by doing. In: Progress
in Motor Control IV: Motor Control and Learning over the Life
Span, August 2–23 2003, Basse-Normandie, 61.
16.Zwierko T., Dąbrowski E., Level of motor anticipation in players
of different sports. In: Szopa J., Gabryś T. (eds.), Directions of
development of scientific research in sport training. Częstochowa
2004, 143–146.
17.Wyżnikiewicz-Kopp Z., Motor coordination abilities in children
and youth. Theoretical and methodological basics [in Polish].
US, Szczecin 1992.
18.Williams M., Perceptual and cognitive expertise in sport. The
Psychologist, 2002, 416–417.
19.Waśkiewicz Z., The influence of anaerobic efforts on chosen
aspects of motor control [in Polish]. AWF, Katowice 2002.
20.Chojnacki T., Selection of children for sports schools in Szczecin
[in Polish]. Studies on the development of physical education
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21.Ryguła I., Zając A., Studies on the structure of motor abilities
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Paper received by the Editors: February 25, 2005.
Paper accepted for publication: July 20, 2005.
Teresa Zwierko
Uniwersytet Szczeciński
Instytut Kultury Fizycznej
al. Piastów 40 b blok 6,
71-065 Szczecin, Poland
e-mail: Teresa_Zwierko@univ.szczecin.pl
HUMAN
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HUMAN
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2005, vol. 6 (2), 129–135
ANALYSIS OF CHANGES IN SABeR FENCING AFTER THE INTRODUCTION
OF ELECTRICAL SCORING APPARATUS
Zbigniew Borysiuk
Faculty of Physical Education and Physiotherapy at Technical University of Opole, Poland
Abstract
Purpose. The introduction of electronic scoring apparatus and changes in fencing regulations essentially altered the fencing
technique and influenced fencers’ effort profile. The aim of the paper was to identify factors that decide about the sports level of
saber fencers, and to formulate practical, methodological solutions applicable to modern training of fencers. Basic procedures.
The research subjects were fencers ranked 1 to 18 on the Polish Fencing Association list in the 1999/2000 season. The tests
conducted pertained to morpho-structural, physiological, psychomotor and temperament-personality factors as well as special
fencing preparation. The regression analysis (stepping model) was used to examine variables that exert the most considerable
influence on the ranking of the contestants under study. Main findings. Application of a three-stage regressive procedure showed
that the factors deciding on the position of the contestants in ranking are physiological parameters with an emphasis on short- and
medium-time efficiency (aerobic and anaerobic processes) and psychomotor conditions. Conclusions. Taking into account the
results in the scope of physiological parameters, it becomes clear that present-day fencers are facing considerable requirements
pertaining to releasing and rebuilding anaerobic energy resources. This is confirmed by high parameters of anaerobic power, HR
LT and medium HR during fencing duels. The significance of speed, reaction accuracy and a high level of visual–motor coordination
in saber fencing point to the need of developing psychomotor properties in shaping nervous conditions during training.
Key words: saber fencing, electronic scoring equipment, effort profile in fencing, evolution of training methods
Introduction
Fencing, including saber fencing, is one of five sports
that have been included in the program of modern Olympic Games since their foundation. Olympic fencing has
developed from an old utilitarian martial art into an elabo
rate sport that requires versatile, physical and psychological skills and preparation. Sports saber fencing has a
century-long tradition. It enjoyed periods of successful
development as well as serious decline, in particular in
the 1970s [1, 2]. Lack of impartial scoring apparatus
in saber fencing, which had been used in foil and epee
for some time, led to overuses of conventional rules of
combat. A result of those practices was replacement of
marked thrusts and parries with actions that would force
referees to award more points. The breakthrough came
in the late 1980s and early 1990s with the introduction
of electrical scoring equipment. For the first time the
electronic scoring apparatus was used during the Fencing
World Championships in Denver in 1989, and was soon
followed by radical transformations in saber fencing
tactics and technique. In 1993, further changes in fencing regulations were introduced, including limitation
of the field of play to 14 m and cutting 2 m off the rear
limit. Next, the inverse step and lunge offensive were
forbidden. All these changes drastically reduced the time
of a saber match and had a tremendous effect on saber
fencers’ training and physical condition requirements.
Modern research into fencing focuses mainly on
creation of a model of fencing mastery, with a particular
emphasis on analysis of somatic, efficiency, psychological and special factors of fencers’ preparation [3–6].
The changes in regulations concerning both the fencing
equipment and time of a fencing match have brought
a need to reconsider fencing in terms of complex studies
using physiological and psychomotor diagnostic tools
[7]. Such a complex approach to fencing is applied to
verify the entire process of fencers’ training in an objective way. Earlier methods can also be useful, providing
they meet the modern research requirements. Taking
advantage of quantitative and qualitative analyses in the
area of sports theory and motoricity, this study aimed
to examine factors of saber fencing mastery and to evaluate the development of saber fencing on the basis of
experts’ opinions.
The following research questions were formulated:
– Which factors related to saber fencers’ training
determine their sports level?
– What has been the effect of the introduction of
electrical scoring apparatus and new regulations
129
HUMAN MOVEMENT
Z. Borysiuk, Analysis of changes in saber fencing
in saber fencing on the factors of saber fencing
mastery?
The study subjects were top Polish national team
saber fencers. Each fencer was assigned a series of specific variables (results obtained in individual tests). To
construct the most complete profile of the contestants,
five areas of factors that affected the subjects’ sports level were examined. The following types of factors were
tested: morpho-structural, physiological, psychomotor,
temperament-personality and special fencing preparation. In statistical analysis, a multidimensional regression
analysis (stepping model) was used to examine variables
that had the greatest influence on the ranking of the
contestants under study.
The subjects were fencers ranked 1 to 18 on the Polish
Fencing Association list in the 1999/2000 season. They
included 10 senior and 8 junior fencers. The seniors
constituted the world top fencing elite; three juniors
were included in the list of 16 top world saber fencers.
All subjects had practiced fencing for at least 7 years; 4
seniors had a much longer fencing experience. It should
be mentioned that 2 juniors aged 20 years in the study
group represented Poland at the European Senior Championships, and one of them won the title of European
vice-champion.
Statistical analysis
The statistical analysis used measurements of ranking
and variability of all characteristics being studied. For
twenty variables under examination the following calculations were used: mean, standard deviation, variability
index, and kurtosis coefficient. These indexes, with the
exception of the BMI variable, indicate insignificant
distribution in relation to normal distribution. Such a set
of indexes allows application of more powerful statistical
tools, e.g., regression analysis [8].
The regression analysis (stepping model) was used to
assess variables that significantly affected the ranking of
fencers (place on the list) with RANK as a dependent va
riable. The remaining 20 variables were regarded as inde
pendent variables of the regression model. All calcula
tions were made using the Stat Soft 6.0 software package.
Somatic examination
– Body mass index (BMI) using the BIA-10/S.C.
impedance analyzer. This computer-assisted device
samples tissue resistance and reactance values
130
as well as tissue volume, and then measures the
percentage of lean body mass.
– Body height and weight measured with Rohrer’s
index according to the following formula: body
weight (grams) × 100/ body height cube (cm).
Special preparation assessment
– 5-meter speed test from flying start with photo
finish,
– Speed and accuracy ‘glove pinning’ test in three
series; the test was performed using a bench propped against the wall bars at a standard angle (70 cm
from the wall). The “pinning” spots corresponded
to the saber target area marked with two tapes
placed on the bench at 100 cm and 170 cm from
the ground.
– Fencing endurance test consisting of moving back
and forth along the piste back, six times in the
on-guard position.
– Test of a combination of three fencing actions,
electronically measured. The test started with
a forward lunge, taking the on-guard position,
face-mask lunge, on-guard position – step backward, feinting attack sideways and return to the
on-guard position. The combination was used as
a form of coach-assisted exercise.
Physiological examination
– Medium heart rate (HR) measured during duel
practice, using the Polar sport-tester.
– Maximal work capacity (VO2max) measured with
the Monark cycloergometer, based on Astrand’s
method:
peak anaerobic power (PP) measured according to the Monark procedure. A 30-second
test with 7.5% body mass load as an inhibiting
force and the ‘flying start’ mode with no load
during the first 5 seconds were selected.
lactate threshold power (LTP) measured to
obtain two values: LT and heart rate during the
lactate threshold (HRLT), according to Ryguła’s procedure [9] based on Conconi’s method.
It allowed calculation of the tendency of the
variables under study (HR and P) as well as the
HR variability range. The subjects performed
submaximal-intensity exercise beginning with
1.25 W/kg load, increased for 0.75 W/kg every
three minutes. The fencers were equipped with
the Polar sport-tester.
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Psychomotor examination
– Visual motor coordination measured using the
cross apparatus in default mode. The subjects
were to press buttons on a coordinate axis to activate respective lights. The test was carried out
three times at the set pace of 50, 70 and 90 impulses
per minute. The test result was calculated as a total
of received stimuli in three consecutive trials.
– Simple reaction time calculated using a computer
program generating 30 light impulses, at various
intervals. The total test result consisted of the
mean reaction speed and, what is important, the
number of errors, i.e. missed stimuli or premature
reactions.
– Choice reaction time. The subjects were to
promptly respond with their left or right hand to
respective light signals. Different sequences of 40
stimuli used signals in two colors. The program
recorded the mean reaction time with the accuracy
of 0.01 s as well as the number of errors.
Psychological examination
– Personality traits measured using H.J. Eysenck’s
Personality Inventory [10]. The extroversion/intro
version level was used in the statistical analysis.
– Temperament traits assessed with the Strelau
Questionnaire, modified by Wjatkin. The following
parameters were examined: intensity of stimulation,
intensity of inhibition, agility of nervous processes.
Results
The 5 m speed test results were regarded as a special
training predisposition. The test corresponded to the
running speed specific to fencing. Numerous saber actions (e.g. lunges lasting from a fraction of a second to
2 or 4 seconds) are very dynamic and involve acceleration in the final stages. The mean results obtained by the
fencers amounted to 1.01, which is only slightly lower
than in the case of the football players and much higher
than in the case of tennis and badminton players.
The fencing endurance test (maximum-intensity
exercise for 40.4 s) is assumed to reflect varied energetic
processes. It is an accurate diagnostic tool used frequently
by fencing coaches. The data from other studies show
higher scores achieved by saber fencers as compared with
other fencers.
The ‘glove pinning’ test results (9.06) proved
very predictive. A closer analysis showed that the test
differentiated the entire study group as the top ranked
fencers achieved results very close to the maximum.
The test of three combined actions revealed insignifi
cant variability in the group. This could be an indication
of the equally high sporting level of all the saber fencers
under study, but it may also point to its inaccuracy.
The measurement of physiological parameters places
the fencers close to the sports level of representatives of
other martial arts. The best Polish fencers’ mean VO2max
value of 57.9 ml · kg–1 · min–1 and their variability up
to about 70 ml · kg–1 · min–1 VO2max show that the top
fencers feature significant maximal work capacity.
Interesting data was obtained in the analysis of lactate
threshold, heart rate, and HRLT, and correlation with
medium heart rate during real fencing duels. The difference between HR LT (152.2) and medium HR (160.1)
shows that a saber fencing duel takes place mainly in
the range of anaerobic processes. Recording using sport
testers can only be used during training duels, since refe
ree’s regulations do not allow using the sport tester during
real contests. It can be assumed that stress-related factors
during real fencing contests raise the HR level to 170–180.
In this context the assessment of the peak anaerobic
power with the Wingate test (10.7 W/kg) is also significant. The results obtained as compared with other
reference data indicate a significant phosphagen power
in the fencers’ lower limbs and their ability of dynamic
‘pick-up’ legwork.
In the assessment of psychomotor predispositions,
the cross apparatus was used as a measure of visual-motor coordination [11]. In the research practice in fencing this instrument is often given preference, as it allows
assessment of higher stages of senso-motor coordination
close to the complex fencing requirements. The subjects
achieved statistically significant results (95.3) performing the test in the most demanding mode. In the last
series the apparatus emitted light signals at the pace of
90 impulses/min (the score of 85 is commonly regarded
as very good).
Significant components of psychomotor predispositions are different types of reaction speeds [12, 13]. The
study focused on the assessment of simple reaction time
and choice reaction time. In both cases the computer
recorded the number of errors. The results obtained
compared with reference data from other sports show
that the saber fencers feature very good time of reaction
to visual stimuli in the simple reaction test (0.18) and the
choice reaction test (0.34). The analysis of the number of
errors in both tests also yielded interesting results. The
131
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Table 1. Statistical measures of ranking and variability of investigated characteristics of fencers (n = 18)
Variable
RANK
BMI (body mass index) (%)
Test of speed 5 m (s)
Variability
index
Standard
deviation
Kurtosis
coefficient
9.5
28.5
5.3
0.000
27.4
346.7
18.6
3.872
1.01
HR (medium heart rate) (a.u.)
0.001
0.038
117.987
40.4
13.8
3.72
0.339
9.06
7.1
2.66
–0.192
Rohrer’s index
1.27
541.6
Specialty test – combination of 3 actions (s)
4.33
‘Glove pinning’ (pts)
–1
–1
VO2max (ml · kg · min )
LTP (lactate threshold power) (W/kg)
HRLT (heart rate during the lactate threshold) (a.u.)
PP (peak power in Wingate test) (W/kg)
57.9
2.1
0.13
19.1
0.12
10.8
0.226
160.1
Fencing endurance test (s)
23.2
0.243
4.243
0.36
0.127
4.3
0.508
0.35
0.961
152.2
37.2
6.1
0.269
10.7
1.2
1.11
–0.120
Simple reaction time (s)
0.18
0.000
0.018
0.590
Number of errors in simple reaction test (a.u.)
0.944
0.997
0.998
0.520
Choice reaction time (s)
0.34
0.001
0.038
–0.264
Number of errors in choice reaction time (a.u.)
4.39
8.95
2.992
1.116
Cross apparatus (a.u.)
95.3
245.0
Strelau – intensity of stimulation processes (a.u.)
44.6
78.5
8.86
–1.175
Strelau – intensity of inhibition processes (a.u.)
42.8
77.7
8.81
0.198
Strelau – agility of nervous processes (a.u.)
61.1
64.5
8.03
–0.192
Eysenck – extroversion/introversion level (a.u.)
34.0
32.9
5.73
–0.796
two top fencers in the study group made no error in the
simple reaction test, and made only one error each in
the choice reaction test.
The temperament-related parameters: intensity of
stimulation (44.6), agility of nervous processes (61.1)
and intensity of inhibition (42.8) reveal the subjects’
significant reactivity, and thus a low level of nervous
efficiency. These parameters indicate a significant correlation with the extroversion/introversion level (34.0)
as a type of personality assessment (Tabl. 1).
In the first stage of the stepping model of regression
analysis for dependent variable: RANK, 16 independent
variables were selected. Four variables were considered
statistically insignificant: medium HR, VO2max level,
combination of three fencing actions, and agility of
nervous processes in the Strelau Questionnaire. The results obtained point to lower significance of parameters
determining aerobic efficiency for the sports level of
saber fencers. The combination of three fencing actions
test was not included in the group of 16 most predictive
132
Mean
15.6
–0.128
factors. This is an indication that the test fails to meet
the accuracy criteria. Also exclusion of the psychological
factor: agility of nervous processes is quite surprising at
this stage of statistical analysis, as this factor together
with the strength of nervous processes should be classified as part of the combination of variables determining
the ranking of fencers, i.e. in the last stage of regression
analysis (Tabl. 2).
In the final stage of the regression analysis for dependent variable: RANK, after removal of the absolute
term, eight factors with the greatest impact on the sports
level of the saber fencers under study were selected.
The factors of choice reaction time, visual-motor coordination (cross apparatus) and simple reaction time are
in the scope of psychomotor conditions. The heart rate
during the lactate threshold (HRLT) and peak power
in the Wingate test (PP) are physiological factors. The
highest statistical significance is related to the somatic
parameter of Rohrer’s index and special training parameter of the fencing endurance test. The lowest statistical
HUMAN MOVEMENT
Table 2. Regression analysis of dependent variable: RANK
R = 0.999, R2 = 0.999, F (16.1) = 12429, p < 0.007, standard error: 0.049
Variable
BETA
Standard
error
BETA
Intercept
B
Standard
error B
T (1)
p
–9.665
1.966
–4.916
0.128
Test of speed 5 m (s)
0.182
0.027
–25.807
3.893
–6.628
0.095
0.306
0.003
–0.104
0.001
–90.482
0.007
–0.543
0.011
–0.125
0.002
–49.970
0.012
0.524
0.010
0.751
0.015
51.072
0.012
–0.225
0.004
–1.074
0.020
–55.741
0.011
–0.426
0.012
–59.887
1.729
–34.633
0.018
0.260
0.006
1.391
0.035
39.224
0.016
Strelau – intensity of stimulation processes
(a.u.)
–0.178
0.003
–0.107
0.002
–47.346
0.013
HRLT (heart rate during the lactate threshold)
(a.u.)
0.418
0.018
0.366
0.016
23.135
0.027
Rohrer’s index
Number of errors in simple reaction test
(a.u.)
‘Glove pinning’ (pts.)
–0.074
0.010
–0.148
0.021
–7.091
0.089
BMI (body mass index) (%)
0.240
0.006
0.069
0.002
42.833
0.015
LTP (lactate threshold power) (W/kg)
0.321
0.010
4.832
0.145
33.236
0.019
Strelau – intensity of inhibition processes
(a.u.)
0.101
0.004
0.061
0.002
26.894
0.024
Eysenck – extroversion/introversion level
(a.u.)
–0.213
0.019
–0.199
0.018
–10.767
0.059
Number of errors in choice reaction time
(a.u.)
–0.064
0.008
–0.114
0.014
–7.971
0.079
Simple reaction time (s)
–0.012
0.006
–3.515
1.921
–1.830
0.318
Table 3. Summary of regression of dependent variable: RANK after the removal of the absolute term
R = 0.997, R2 = 0.994, F(8.10) = 212.81, p < 0.000, standard error: 1.11
Variable
BETA
Standard
error
BETA
B
Standard
error B
T (1)
p
2.095
0.331
0.559
0.088
6.332
0.000
–0.915
0.271
–0.920
0.273
–3.369
0.007
Rohrer’s index
–0.197
0.028
–0.090
0.013
–7.138
0.000
–1.503
0.250
–47.652
7.937
–6.004
0.000
2.509
0.443
0.178
0.032
5.661
0.000
–1.005
0.190
–0.113
0.021
–5.292
0.000
0.142
0.039
1.134
0.320
3.548
0.005
–0.369
0.126
–0.088
0.030
–2.918
0.015
HRLT (heart rate during the lactate threshold)
(a.u.)
Number of errors in simple reaction test
(a.u.)
Strelau – intensity of stimulation processes
(a.u.)
133
HUMAN MOVEMENT
significance (0.015) is observed in Strelau’s intensity of
stimulation test (Tabl. 3).
Discussion
The assessment of physiological factors shows that
the saber fencers are facing considerable requirements
pertaining to releasing and rebuilding anaerobic energy
resources. This can be confirmed by the high parameters
of anaerobic power, HR LT and medium HR recorded
during fencing duels. An important conclusion for fencing
coaches is that certain elements of individual training
sessions and legwork practice should be characterized
by high intensity and short duration, especially in the
preliminary stage of preparation and shortly before impor
tant contests [14, 15]. It must be stressed that fencing
contests usually last two days, or even three days during
the Olympic Games and world championships (including
team competitions). Therefore, optimal preparation of
saber fencers should take into account long-time efficiency training. As the study showed, the mean VO2max of
saber fencers amounted to 57.96 ml · kg–1 · min–1. Saber
fencing training should focus on development of speed
predispositions on the basis of overall endurance. The
final results of the regression analysis also proved the
significance of speed, reaction accuracy and the high
level of visual-motor coordination. It can be stated that
psychomotor efficiency depends on resistance to fatigue
and speedy regeneration of the psycho-physiological
functions.
In the case of psychological factors the main emphasis
was placed on temperament traits and extroversion/intro
version as indicators of the subjects’ personality [16, 17].
The results obtained show that the scope of temperament
and personality traits of saber fencers is wide, although
the so-called master model features significant strength
of the nervous system. This is confirmed by the dominance of stimulation processes over inhibition processes.
At the same time the saber fencers were characterized
by significant agility of nervous processes, which remains in accordance with some earlier studies [18, 19]
indicating a low level of perseverance in fencers (all
weapons) in the Catell test. Many researchers [20, 21]
point to significant correlations between the strength of
stimulation processes and the considerably high level of
fencers’ extroversion. The above conclusion does not
rule out a possibility that the world championship medalists may include contestants with a different profile, e.g.
introverts with dominating inhibition processes. In this
context, Czajkowski’s [22] comment that, “the greatest
134
fencing successes are achieved by choleric persons who
can control themselves and phlegmatic persons who can
stimulate themselves” seems quite appropriate. There is
no doubt that this statement precisely reflects the specificity of present-day saber fencing, in which offensive
actions surpass to a certain degree counterattacks and
defensive actions. Coaches’ observations seem to confirm
the necessity of balancing the opposite nervous processes,
which is conducive to optimal solution of technical and
tactical problems in saber fencing.
On the basis of earlier observations of Tyszler and
Tyszler [2], and Czajkowski [5] it can be concluded
that, from the tactical point of view, the former fencing
masters required much more time to score points. The
decision to make a hit used to be preceded with a few
seconds long maneuvering on the piste, which often led
to saber duels lasting from 5 to 10 min of the actual fight
time. Another factor affecting the duration of duels was
inaccurate judgment based on voting of five fencing
officials, which often led to referee’s errors. In comparison, observations of the present-day duels show that the
actual fight time until 15 hits are recorded ranges from
50 s to 2 min. The judgment of one hit takes from 2 to 5
s on the average. The electronic scoring equipment emphasized the speed and precision of lunges from the wrist
over the cutting force. The aforementioned regulation
changes altered the saber fencer’s equipment. Similar
to foil fencers the saber fencers now wear metallic plastrons combined with the face mask and protective metallic
gloves. Accurate recording of hits has also affected the
fencing pace (conventional time intervals) as well as
technique of attacks on the blade. The overall image of
saber duels is a more dynamic one, based on anaerobic
and mixed energetic processes. As it is stressed by the
aforementioned authors, fencing training should consist
of exercises that would allow development of energetic
processes. In the theory of sports training, present-day
fencing, including saber fencing, can be classified as
a speed-endurance sport with an emphasis on anaerobic and aerobic processes and the role of psychomotor
properties.
In conclusion, it must be stated that the factors
which determine the subjects’ ranking are physiological
parameters with an emphasis on short- and medium-time efficiency, i.e. anaerobic and aerobic processes,
and psychomotor parameters such as simple reaction
time and visual-motor coordination. Another important
factor is Rohrer’s index. Statistical analyses (multidimensional regression and factor analyses) applied in
HUMAN MOVEMENT
biological sciences, among other factors of the sports
level, are used to identify morphostructural components.
The high level of statistical significance of the fencing
endurance test makes it an important predictor of saber
fencing achievements. It must also be noted that owing
to its duration, from the psychological point of view,
the endurance test is of mixed character. This can also
be a proof of aerobic-anaerobic specificity of the saber
fencers’ effort profile.
Conclusions
1. The statistical analysis (regression analysis) showed
that the ranking of present-day saber fencers is determined
by short-time efficiency and psychomotor predispositions. Another important factor is the somatic condition
of body height/weight and psychological resistance
expressed by the strength of stimulation processes in
the temperament test.
2. In the opinions of experienced coaches it must be
stipulated that changes in fencing regulations have contri
buted to evolution of technique and effort capacity of saber
fencers. Present-day saber fencing should be classified
as a sport in which motor coordination factors exert the
decisive influence. In terms of training it is a speed and
endurance sport with a great emphasis on anaerobic
predispositions.
References
1.Lukovich I., Fencing. Alfoldi Printing House, Debrecen 1986.
2.Tyshler D., Tyshler G., Fencing. Physical Education and Science
Press, Moscow 1995.
3.Bandach L., Fencer’s style of fighting [in Polish]. Sport Wyczynowy, 1998, 7–8, 44–47.
4.Iglesias X., Rodriguez F., Dynamic strength testing of fencers:
profiling with relation to age, gender, weapon and performance.
Proceedings of the 6th Annual Congress of the ECSS. Cologne
24–28 July 2001, 1159.
5.Czajkowski Z., About the specificity of energy and coordination
abilities [in Polish]. Sport Wyczynowy, 2001, 11–12, 37–43.
6.Szabo L., Fencing and the Master. Korvina Kiado, Budapest 1977.
7.Ryguła I., Taking advantage of the optimalization model in athletic
training [in Polish]. Sport Wyczynowy, 1998, 11–12, 37–43.
8.Ryguła I., An optimal control methods in kinesiology and sports.
IMEKO TC Conference, Dubrownik 1998.
9.Ryguła I., Borysiuk Z., Conditions of sporting level of fencers
at master stage of training. J Hum Kinetics, 2000, 4, 67–85.
10.Paisey T.J.H., Mangan G.L., The relationship of extroversion,
neuroticism and sensation – seeking to questionnaire-derived
measures of nervous system properties. The Pavlovian J Biol
Sci, 1980, 15, 123–130.
11. Raczek J., Juras G., Waśkiewicz Z., Motor co-ordination assessing tests [in Polish]. Sport Wyczynowy, 2001, 1–2, 17–21.
12.Bernstein N.A., The Coordination and Regulations of Movements. Pergamon, Oxford 1967.
13.Schmidt R., Motor Learning and Performance. Human Kinetics,
Champaign 1991.
14.Czajkowski Z., Theory, practice and methodology in fencing.
Advanced course for fencing coaches [in Polish]. AWF, Katowice
2001.
15.Dryukov V., Pavlenko Y., Shadrina V., Training process intensification for skilled athletes in fencing at pre-competitive stage
of preparation. 8th Annual Congress ECSS. July 9–12, Salzburg
2003, 58.
16.Borysiuk Z., Factors Determining sport performance level for
fencers at the preliminary and championship stages of their training.
Proceedings of the 5th Annual Congress ECSS, July 19–23 2000,
Jyvaskyla 721.
17.Eysenck H.J., The scientific study of personality. Routledge and
K. Paul, London 1985.
18.Heroux P., Some aspects of fencing psychology. The Sword,
1974, 4, 16–27.
19.Moris T., Summers J., Sport Psychology. Theory Applications
and Issues. Wiley and Sons, Brisbane 1995.
20.Roberts G.C., Motivation in Sport and Exercise. Human Kinetics,
Champaign 1992.
21.Sage G., Does sport affect character development in athletes?
J Phys Edu, Recreation and Dance, 1998, 1, 15–18.
22.Czajkowski Z., Elementary conception of reaction in fencing.
Fencing Master, 1970, 6, 61–78.
Paper received by the Editors: January 16, 2005.
Zbigniew Borysiuk
Politechnika Opolska
Wydział Wychowania Fizycznego i Fizjoterapii
ul. Prószkowska 76
45-758 Opole, Poland
e-mail: zbig@po.opole.pl
135
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2), 136–148
CURRENT KNOWLEDGE IN STUDIES ON RELAXATION
FROM VOLUNTARY CONTRACTION
Katarzyna Kisiel-Sajewicz*, Artur Jaskólski, Anna Jaskólska
Department of Kinesiology, Faculty of Physiotherapy, University School of Physical Education, Wrocław, Poland
Abstract
The present review is focused mainly on neural regulatory mechanisms of early and late relaxation from voluntary contraction based on
electromyography (EMG) and mechanomyography (MMG) as well as on brain activity and encompass mechanisms of muscle deactivation and its motor unit derecruitment, and also central mechanisms. However, basic cellular level mechanisms of muscle relaxation are
also mentioned when necessary. The review of the literature up to date shows that the early phase of voluntary relaxation executed
with slow speeds is governed by reduction of motor unit firing rate while late relaxation phase – by reduction of motor unit recruitment
level. But it is not known whether the strategy is the same in relaxation executed at greater speeds. Antagonist muscle has been
shown to affect relaxation speed from voluntary contraction, but the motor unit derecruitment strategy of such muscles is not known.
The voluntary muscle relaxation is mediated by preparatory mechanisms similar to the voluntary muscle contraction, however,
further studies are necessary to localize the inhibitory motor centers and to investigate the influence of the speed of the relaxation
and/or the force level on preparatory mechanisms of relaxation from voluntary contractions.
The early and late phases of relaxation are differently affected by joint angle and age, which is partly related to different changes
in EMG activity of agonist and antagonist muscles, and is accompanied by different MMG activity of those muscles. The voluntary
relaxation mechanisms are also dependent on the muscle being tested.
Key words: voluntary relaxation, early and late phases, agonist and antagonist EMG and MMG activities, EEG, joint angle, age
Introduction
Mechanisms of force production have been studied
quite intensively, and recent research into motor control
provided insight into such mechanism as the recruitment
order of motor units [1–3], the interaction between recruitment and firing rates [4–6], and the interaction
between the force output of the muscle and the firing
rate of motor units [2, 4, 7–9]. However, little attention
has been paid to control strategies for muscle relaxation
despite the fact that daily living activities consist of sequential and repetitive motor tasks that contain elements
of muscle contraction and relaxation (termination). This
means that changes in relaxation resulting, e.g. from
joint motion (muscle length) or/and age-related neuro-mus
cular deterioration can potentially affect execution of
a motor task. Thus, understanding of muscle relaxation
mechanisms is needed and is of practical usage.
Although mechanisms on cellular level contribute to
isolated muscle relaxation and cannot be ignored, relaxa
tion following voluntary contraction is additionally governed by neural mechanisms controlling not only a given
agonist muscle group, but also changes in agonist-anta-
136
gonist activity and their interplay. Detailed information
concerning cellular mechanisms of isolated muscle relaxation can be found in an excellent review of Gillis [10]
and following papers [e.g. 11–14], while relaxation from
voluntary contraction is the subject of the present review
with the main focus on neural regulatory mechanisms
based on analysis of electrical (EMG) and mechanomyo
graphical (MMG) signals, as well as on brain activity
recordings. The neural mechanisms responsible for volun
tary relaxation encompass central mechanisms and also
mechanisms of muscle deactivation, particularly their
motor unit derecruitment. Specific issues also addressed
in this review refer to methods used to study mechanisms
of relaxation during voluntary contractions and some factors influencing relaxation such as muscle length and age.
Before discussing the relaxation mechanisms a characteristic of the mechanical nature of force decay (relaxation) needs to be given to help us understand such
mechanisms.
Force-time profile of twitch, tetanus
and voluntary contractions
Figure 1 shows force-time profiles for twitch, tetanus
and maximal voluntary contractions (MVC).
Relaxation from isometric tetanus contraction has two
phases. The first, slow relaxation is followed by fast, expo-
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force
isolated
force
K. Kisiel-Sajewicz et al., Current knowledge in studies on relaxation from voluntary contraction
unfused tetanus
force
maximal voluntary
contraction
time
Figure 1. Force–time relationship in twitch (upper panel),
tetanus (middle panel) and maximal voluntary contraction
(lower panel)
nential force decay [10, 15–18]. During the slow relaxation phase force decays in a linear fashion (up to ca.
80–75% MVC), hence it is called linear, and the decay
is relatively slow with no sarcomere length change [15,
17, 19]. The relaxation during the slow phase is uniform
within the entire muscle length and is not sensitive to
stimulation frequency [18].
On the other hand, the second phase of relaxation
(from ca. 80% MVC to baseline) is characterized by
exponential, fast force decay with sarcomere length
change [15, 19], and the relaxation in this phase is
non-uniform within the muscle length and is related to
stimulation frequency inducing contraction [18].
Despite the fact that the shape of the force decay from
voluntary contraction can deviate from that recorded
from isolated muscle (as a result of off-phase motor unit
derecruitment and involvement of many muscles in voluntary contraction), it seems that during voluntary
contractions there are also slow and fast relaxation phases.
This assumption results from the fact that Gurfinkel and
co-authors [16, 20] recorded the two phases of relaxation
in human muscles during electrically induced unfused
tetanus contraction.
The slow phase of relaxation depends mainly on the
rate of Ca2+ uptake [12, 21]. During the fast phase of
relaxation intracellular calcium concentration decreases
slowly or there can be even a transient increase [22].
Thus, fast phase of relaxation is only partially dependent
on the rate of Ca2+ uptake, but mainly is dependent on
the cross-bridge dissociation rate [12, 21, 23].
In reality, most authors choose different parameters to
characterize relaxation; some of the parameters cover the
slow relaxation and a part of the fast relaxation. Among
them is half relaxation time (Fig. 2). This is the most
popular parameter, which is used to assess relaxation
mechanisms on isolated muscles and during relaxation
from voluntary contraction [24–26]. The half relaxation
time is defined as the time needed to decrease force to
50% of maximal isometric force. However, because the
half relaxation time includes the slow relaxation and
a part of the fast relaxation phase, the authors [27–29]
also use parameters that represent and describe single
phases during voluntary contraction, e.g. early relaxation (relaxation from 95 to 80% of force recorded
at the emission of the contraction ending signal), late
relaxation (relaxation from 80% of force recorded at the
emission of the contraction ending signal up to baseline),
late relaxation 50–20% (relaxation from 50 to 20% of
force recorded at the emission of the contraction ending
signal), late relaxation 20–0% (relaxation from 20% of
force recorded at the emission of the contraction ending
signal up to baseline) (Fig. 2).
Another parameter, which is very often used as a relaxation mechanism index during relaxation from volun
tary contraction, is maximal rate of relaxation (Fig. 2).
The maximal rate of relaxation is defined as the greatest
slope of force decrease, which is usually recorded at
75% to approximately 60% of the maximal voluntary con
traction [29–33]. Thus, maximal rate of relaxation charac
terizes fast phase of relaxation. It should be emphasized
that terms fast and slow refer to the phases of relaxation
while early and late refer to the velocity of muscle de137
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xa
t
io
n
signal
ha
80
la
te
50 re
% lax
-2 at
0% io
n
force [%]
lf
re
la
100
50
te
20 rela
% xa
-0 ti
% on
6
la
20
1
early relaxation
time
2
3
4
5
late relaxation
1 – early relaxation (relaxation from 95 to 80% of force recorded at the emission of the contraction ending signal),
2 – half relaxation (relaxation from 95 to 50% of force recorded at the emission of the contraction ending signal),
3 – late relaxation 50–20% (relaxation from 50 to 20% of force recorded at the emission of the contraction ending signal),
4 – late relaxation 20–0% (relaxation from 20% of force recorded at the emission of the contraction ending signal up to baseline),
5 – late relaxation (relaxation from 80% of force recorded at the emission of the contraction ending signal up to baseline),
6 – maximal relaxation rate
Figure 2. The indices describing the course of force decay after maximal voluntary contraction
-activation. Thus, to avoid confusion throughout the text
of the present review the slow and fast relaxation will
be used when talking about cellular mechanisms of relaxa
tion phases while the early and late when describing
phases of force decay of an entire muscle group (muscles’
de-activation).
A reader should also be aware of the fact that all the
relaxation indices can be expressed in absolute terms
(time in ms or s, rates in N/s) or in relative terms [%, %/s],
which is of significance when considering the effect of
joint angle and age on relaxation. For example, when
a rate of relaxation is expressed in N/s unit its changes
with joint angle can behave similar to that in maximal
isometric force, while expressed in relative unit are independent of the absolute force level and thus the joint
angle effect may be different from that of the force.
Whenever necessary, the present review of literature
relates to the relaxation phases and their parameters
described above.
Central mechanisms of relaxation and role
of EEG to disclose the influence of motor
commands
The central neural factors were recently found to be
of significance in control of the voluntary relaxation
138
since they are responsible for initiation of the relaxation
process.
Movement-related cortical potentials (MRCPs) are
defined as brain potentials associated with self-paced,
voluntary movements [34–36]. MRCPs are of great
interest because they are expected to help elucidating
the neuronal mechanisms participating in the movement
preparation, initiation, execution and feedback control
[37–41]. Currently it is accepted that pre-movement
components of MRCPs consist of at least two subcomponents: the earlier slow negativity, Bereitschaftspotential (BP) and the late negative slope (NS’) [35]. These
potentials are most likely to represent the function of
the primary and supplementary motor areas, as shown
by subdural recording in patients with interactable epilepsy [42–45]. Till 1995 all studies on MRCPs recognized those potentials in association with the initiation of
self-paced voluntary muscle contraction, i.e., “positive
motor phenomenon”, and no studies have been reported
concerning voluntary, pure relaxation of the ongoing
muscle contraction, i.e. “negative motor phenomenon”. Although Dimitrov [46] reported the presence
of Bereitschaftspotential associated with termination
of the voluntary finger movement, he did not monitor
the antagonist muscles, nevertheless concluded that the
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Bereitschaftspotential was related to contraction of the
antagonists rather than to pure relaxation. Terada et al.
[47] suggest that voluntary muscle relaxation has similar
preparatory mechanisms to voluntary contraction at the
cortical level. Furthermore, the overall similarity of waveforms to those of Bereitschaftspotential and negative
slope associated with voluntary muscle contraction suggests that the main cortical generators of those potentials
might be common for both tasks, namely the primary and
supplementary motor areas according to the results of
subdural recording [43–45]. However, when Terada et al.
[47] made quantitative and topographical comparison of
MRCPs during contraction and relaxation, they observed
some differences between the two tasks. First, the onset
of Bereitschaftspotential was earlier and its duration
was longer for the relaxation than for the contraction
task, suggesting that the voluntary muscle relaxation
needs longer preparation than the voluntary contraction.
However, it is also possible that the different movement
velocities, slower in the relaxation task than in the contraction task, might result in a different onset time [48].
Secondly, the amplitudes of Bereitschaftspotential and
negative slope were larger at the contralateral centroparietal area for the relaxation task than for the contraction
task. It is possible that the primary motor area is more
active in the preparation for the voluntary muscle relaxation than for the contraction task. However, in the
foot relaxation task there was no significant difference
in the amplitudes of Bereitschaftspotential or negative
slope between the two tasks at any electrode, indicating
that there is no clear difference in the cortical activity
between the two tasks [49]. On the basis of their own
observation of the hand muscle relaxation and the foot
relaxation task Terada et al. [49] concluded that voluntary muscle relaxation is mediated by preparatory
mechanisms similar to the voluntary muscle contraction
in the contralateral primary motor cortex and possibly in
the bilateral supplementary motor areas, but not in the
primary negative motor area. In addition, some functional differences might exist in the bilateral frontal regions
(prefrontal area, supplementary negative motor areas)
between the relaxation and contraction tasks.
Mechanism of negative motor phenomena
Negative motor response that was defined as an
inability to perform voluntary movement or to sustain
voluntary muscle contraction was seen when a part of
the premotor cortex just above the sylvian fissure or
the anterior part of the supplementary motor area was
electrically stimulated [50]. Hence, these areas were
called “primary and supplementary negative motor areas”, respectively [51]. Terada et al. [47] noted that the
positive field of Bereitschaftspotential for the relaxation
task was located in the bilateral frontal area, but it might
be possible that the positive field was generated in the
supplementary negative motor area.
In experimental studies, it was reported that ablation
of the cerebellum or cooling of the dentate nucleus dimi
nished the surface-negative, depth-positive field potential recorded in the motor cortex of monkey preceding
self-paced movement [52, 53]. Those experimental data
suggest that Bereitschaftspotential and negative slope
represent the excitatory postsynaptic potentials (EPSPs)
of the corticomotor neurons as a result of the facilitatory
input through the cerebello-thalamo-cortical pathway.
Furthermore, disynaptic inhibition of the spinal motor
neurons mediated by group Ia interneurons and pure
inhibition of motor unit discharge without additional
increase of motor unit were demonstrated by electrical
stimulation of the corticomotor neurons in monkey [54].
It was also suggested that some corticomotor neurons
might have an inhibitory effect on spinal motor neurons:
inhibitory corticomotor neurons [55–58]. The waveforms of Bereitschaftspotential and negative slope for
the relaxation task were, as a whole, similar to those
for the contraction task with the maximum in the centroparietal area [47]. Those experimental data suggest
that Bereitschaftspotential and negative slope preceding
voluntary, self-paced relaxation may represent the excitatory postsynaptic potentials (EPSPs) on the inhibitory
corticomotor neurons.
The precise localization of inhibitory motor centers
requires further studies by using other non-invasive
methods such as assessment of blood flow by positron
emission tomography. Recently, by using the functional
magnetic resonance imaging (fMRI) technique, Toma
et al. [59] discovered transient increases of activity of
the primary (M1) and supplementary motor (SMA) areas
in association with the voluntary muscle relaxation.
However, the temporal properties of the activation of
those areas were not clearly different between the muscle
relaxation and contraction tasks [59], most likely due to
the delay and dispersion of the hemodynamic response
detected by the fMRI technique [60, 61]. To clarify the
cortical mechanisms involved in motor inhibition Toma
et al. [62] used modulation of cortical rhythms around 20
Hz during voluntary muscle relaxation and during muscle contraction, using a whole head type neuromagne
139
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tometer [62]. The authors suggested that the voluntary
muscle relaxation involves the modulation of central
rhythms starting a few seconds before the actual event,
and the 20-Hz desynchronization has a similar temporal
property in the muscle relaxation and contraction. The
20-Hz synchronization in the contralateral central area
after the muscle relaxation may be associated with the
temporarily arrayed termination of the ongoing muscle
contraction [62]. Thus one can see that some mecha
nisms of relaxation are still poorly understood. Therefore, further studies are necessary to find localization of
inhibitory motor centers and to investigate the influence
of relaxation speed and/or the force level in different
muscles on preparatory mechanisms of relaxation from
voluntary contractions.
Peripheral mechanisms of relaxation
and role of electromyography (EMG)
and mechanomyography (MMG)
to disclose the influence of motor commands
and muscle mechanics
One of the neural mechanisms involved in a control of
relaxation from voluntary contraction is the mechanism
controlling deactivation strategy of agonist and antagonist muscle groups and the derecruitment of their active
motor units. To assess these processes in a non-invasive
manner, two recording methods (EMG and MMG) can
be used. Although, there are some limitations to spectral
analysis of the surface EMG signal as a technique for the
investigation of muscle force control [63], the time and
frequency domain analysis of surface EMG (sEMG) is
a common method used to assess motor unit activation
during voluntary contractions [64–66]. The EMG and
MMG were widely used to assess motor unit recruitment
and motor unit firing rate modulation (rate coding) under
variety of experimental conditions during contraction
[2, 65–77], while usage of both methods for relaxation
assessment is sparse [28, 78].
It is generally assumed that EMG activity ceases well
before the beginning of force relaxation, however the
results of Jaskólska et al. [28] have shown that the agonists are still active during the slow relaxation, and so
the antagonists during fast relaxation. The authors found
that, during voluntary contractions, the speed of slow
relaxation is related to the cessation of synergist activity, while antagonist activity affects late relaxation force,
which suggests that there is a time delay between synergist
and antagonist inhibition processes. However, this hypo
thesis needs to be tested by simultaneous recording of
140
EMG, MMG and EEG signals from agonist and antagonist muscles during relaxation done with different speeds.
On the other hand, Terada et al. [47] studying movement-related cortical potentials associated with voluntary muscle relaxation from the extended position in the
wrist extensors, recorded trials with and without EMG
activity of antagonist muscle, although they observed the
EMG activity of the antagonist muscles before and/or after
the movement onset. Thus, further studies concerning
the role of antagonist muscles in voluntary relaxation
of different muscle groups are needed. The contribution
of the antagonists in relaxation can be muscle group or
motor task specific, e.g. small–big muscle group. Thus,
simultaneous recording of EMG, MMG signals of
agonists and antagonists and EEG during relaxation of
different muscle groups done at a different speed can be
applied to expand the knowledge on voluntary relaxation
mechanisms.
The second method that can be used to assess relaxa
tion nature is mechanomyography (MMG). Mechano
myography is a non-invasive method of investigating
muscle function that involves recording and quantifying
the lateral oscillation of contracting skeletal muscle fibers
[79]. The lateral oscillations recorded as MMG include
[79] gross lateral movements at the beginning and end of
a muscle action which are generated by nonsimultaneous
activation of muscle fibers, smaller lateral oscillation at
the resonant frequency of the muscle, and changes in
dimension of the active fibres.
During relaxation from MVC, there is a decreasing
muscle electrical activity resulting in dimensional changes of the muscle structures causing lateral muscle
oscillations, which can be recorded as the MMG [79–82].
Large MMG signals were observed during relaxation
from fused and unfused tetani of isolated motor unit in
rats [83, 84]. Bichler [83] noted an increase of MMG
amplitude during relaxation in isolated muscles. With
respect to the early and late relaxation, Jaskólska et al.
[28] noted that MMG amplitude (RMS) of synergist and
antagonist muscles increased during both phases (compared to their activity at MVC). Moreover, the authors
[28] indicated that during the early relaxation from MVC
the increase was smaller than that during the late relaxation in the biceps brachii (BB; synergist) and triceps
brachii (TB; antagonist), but was similar in brachioradialis muscle (BR; synergist). The discrepancy may have
resulted from a different deactivation time of the BR
muscle compared to the BB and TB. Jaskólska et al. [28]
suggested that, the smaller MMG RMS during the early
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phase might be related to the fact that during the slow re
laxation there are no sarcomere length changes, and thus
dimensional changes of the working muscle fibers are
small. During the fast phase, the relaxation is non-uniform along the muscle fiber length and thus comparable
big changes in fiber dimensions occur [10, 12, 15, 85].
The literature data also have shown that the value
of MMG amplitude is dependent on the amplitude and
velocity of tension changes during relaxation from fused
and unfused tetani of isolated motor unit in rats [83, 84].
When the dependence of MMG amplitude during early
and late relaxation from MVC on amplitude and velocity
of torque changes was tested [28], a different relationship was shown in synergists and antagonist (biceps
brachii, brachioradialis and triceps brachii). During the
late relaxation a change in muscle force (independent
of time) contributed mainly to the MMG amplitude
in the triceps brachii (antagonist) and biceps brachii
(agonist) muscles, but not in the brachioradialis muscle
(synergist). During the early relaxation, the MMG RMS
was positively related to the amplitude of force changes
only for agonist muscle (biceps brachii). Moreover, an
increase in velocity of force changes contributed to the
MMG RMS during the early relaxation in the biceps
brachii (agonist) and triceps brachii (antagonist) muscle
(but not in brachioradialis). During the late relaxation,
the MMG-velocity relationship was generally found in
the synergists (not in the antagonist). Thus, the effect of
the amplitude and velocity of tension changes during vo
luntary relaxation on MMG amplitude is muscle specific.
It is worth noting that force and MMG activity do not
occur in the same time course. Orizio et al. [78] noted
that the changes in muscle lateral displacement are present at different time than the force signal during relaxa
tion phases of tetani induced by electrostimulation. One
of the main factors influencing the rate of force reduction
of a muscle fiber during the relaxation phase is the rate
of calcium re-uptake in the sarcoplasmic reticulum [86].
Because of the decrease in the intracytoplasmic [Ca2+]
the regulation proteins troponin and tropomyosin can
block the acto-myosin interaction allowing the sarcomere to return to its resting length value by pulling the
elastic elements stretched during the previous activity.
If, as has been suggested, the shortening of the contractile elements is a determinant of the muscle transverse
diameter changes, the re-elongation during relaxation
may determine the muscle surface movement towards
its basal position [78]. Assuming that the Ca2+ reuptake
could affect the force and MMG transients to the same
extent, their decaying rate should be similar. In reality
however, during the relaxation the force transient was
much faster than the MMG one. A possible explanation
of these results can be related to changes in the intra-muscular pressure [78]. During maximal contraction the
increase of the intra-muscular pressure (PIM) blocks the
arterial flow and increases the muscle blood outflow by
the venous site [87]. In contrast, during the relaxation
phase, the PIM decrease may lead to the restoration of
the spatial relationships between the blood vessels and
the muscle fibers with a possible influence on the overall
muscle geometry and hence on the dynamics of the
MMG [78].
In addition to pressure changes, during tetanic contraction each fiber may bulge and as a consequence the
space between fibers may decrease dramatically while
the interstitial fluid may be squeezed outside of this space. This hypothesis has also been posed by Tsuchiya et
al. [88]. The re-occupation of the inter-fiber space by
the interstitial fluid may take time after the contraction
phase, thus slowing the MMG’s return to its pre-stimulation value.
To investigate the motor unit recruitment and derecruitment strategy during voluntary isometric contractions
with slow speed Orizio et al. [89] used MMG time and
frequency domain analysis as a tool. They noted that
during isometric efforts from 100 to 0% of maximal
voluntary contraction force decrease is obtained with
reduction of motor unit firing rate between 95 and 80%
MVC, and reduction of motor unit recruitment level
between 80 and 15% MVC indicating a different motor
units strategy during early and late relaxation. But, this
hypothesis still needs to be tested during voluntary
relaxation of different muscle groups executed at a
different speed.
Factors affecting relaxation
from voluntary contraction
Relaxation from voluntary contraction
– an effect of muscle length
Because of the different events occurring during the
slow and fast relaxation at muscle fiber level [10, 15, 28,
85, 90, 91] and activity of agonist and antagonist muscles
during relaxation [28] one can expect a different response
of relaxation parameters to muscle length (joint angle)
changes. Thus, this part of the review deals with the
relaxation–joint angle relationship.
In a study on isolated muscle in twitch and tetanus the
influence of muscle length on half and total relaxation
141
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time, and maximal rate of relaxation were noted [10,
21, 92, 93]. Pagala [21] showed that the half and total
relaxation time increased linearly with the length change
of frog sartorius muscle from 0.7 to 1.4 times rest length,
and there was a bigger increase in total relaxation time
than in the half relaxation time. The maximal rate of
relaxation decreased with both decrease and increase of
length compared to the rest length. Wallinga-de Jonge
et al. [94] found that the maximal relaxation rate of
the extensor digitorum longus (fast muscle) and soleus
muscle (slow muscle), expressed in relative terms res
ponded the opposite way to length change. Thus, in
a muscle with a mixed fibres composition, it might be
expected that the influence of muscle length on the relative maximal relaxation rate can be small. Indeed, as has
been shown by Jaskólska et al. [29] during maximal vo
luntary contraction of elbow flexors (mixed muscle fibre
composition), the maximal relaxation rate expressed in
relative units changed a little with joint angle.
The relaxation from voluntary contraction was not
tested by many authors, thus not much is known about
the changes of such relaxation with joint angle in humans.
Figure 3 shows an example of voluntary relaxation at
a different elbow joint angle.
Jaskólska and co-authors [28] found that the rates
of early and late relaxation of the elbow flexor muscles
during voluntary contraction were differently affected
by joint angle in young females. The early relaxation
rate decreased at joint angle less (Ls) than the optimal
angle (Lo; the angle at which MVC force had a maximal
Figure 3. An example of force–time characteristic recorded
in a subject during maximal voluntary contraction
with a relaxation course on the right side of curves
and force development on the left side of the curves
142
value) while the late relaxation rate increased at Lo and
Ls compared to Ll (joint angle bigger than the Lo) [28].
In young men, Jaskólska et al. [29] recorded similar joint
angle-related changes in relaxation phases, but the effect
was smaller (did not reach a level of statistical significance) compared to young women. The gender discrepancy
can be related to female hormones fluctuation [95], and
to potential gender differences in muscle composition,
architecture, structure and properties (e.g. muscle stiffness), which in turn can affect joint angle–relaxation
relationship, and thus may result in a different strategy
of individual muscle activation and deactivation with
muscle length (joint angle).
The changes in relaxation rates with joint angle [28]
are accompanied by different changes in EMG activity
of agonist and antagonist muscles with joint angle [28].
The EMG amplitude of the brachioradialis muscle during
the slow and fast relaxation is bigger at Ls (short muscle
length). The biceps brachii EMG amplitude during the
slow and fast relaxation does not change with elbow joint
angle. The EMG amplitude changes of the triceps brachii
muscle (antagonist) with elbow joint angle are different
than the EMG amplitude changes of the synergist mus
cles. The opposite behaviour of the EMG amplitude of
synergists and antagonist at different joint angles can
result from the fact that the triceps brachii has a short
length at angle bigger than optimal (Ll), while the biceps
brachii and brachioradialis muscles have long lengths
at that angle. It is also possible that the different EMG
activity of the agonist and antagonist muscles at different
lengths may be related to the specific activation of the
muscle spindles. Additionally, the mechanical advantages
of all muscles depend on joint angle [96] and each muscle
may operate on different limb (ascending or descending)
of the force-length relationship reaching the plateau at different joint angle [97]. The EMG amplitude depends on
the number of active motor units. In agreement with Van
Zuylen et al. [96] and Nakazawa et al. [98] suggestion,
the muscle with the larger mechanical advantage may
receive the larger activation. Thus, the EMG amplitude
during relaxation from voluntary contraction is affected
by joint angle.
To assess whether the changes in agonists and antagonists activity affect the speed of relaxation during
voluntary contraction and whether this effect depends
on a muscle’s length, Jaskólska et al. [28] calculated
correlation between relaxation rates (expressed in relative units) and EMG amplitude (RMS) and its percent
change during respective relaxation phase. It has been
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shown by the authors that relaxation from voluntary
contraction depends on deactivation of agonist muscles
and their motor units de-recruitment, and antagonist
muscles co-activation. They also found that the speed
of cessation of the antagonist muscle activity is affected
by joint angle differently than the activity sustained at
a steady level, with the slowest cessation of triceps brachii electrical activity at its short length, and a fastest
cessation at its long length. This fact explains a smaller
relative rate of late relaxation at short length compared
to long length because the late relaxation was related
to triceps brachii muscle activity, irrespective of elbow
joint angle [28]. A different cessation of triceps brachii
electrical activity at its short and long length probably
resulted from a different sensory input at those lengths,
which might affect the speed of withdrawal of the input
going to pyramidal neurons mediated by the intracortical
inhibitory neurons [59]. Jaskólska et al. [28] also noted
that irrespective of the joint angle the rate of early relaxa
tion phase was dependent on how fast the synergist’s
electrical activity was terminated during a voluntary
contraction, while such an effect was not found in the
late relaxation rate.
Since electrical activity of a muscle is associated with
mechanical counterpart known as MMG the last one can
potentially change with joint angle, too. The MMG is
a mechanical phenomenon related to active and passive
deformation of the muscle surface that is recorded during
relaxation [83]. The passive stiffness is primarily produced by stretching the connective tissue and therefore
it depends on muscle length [99]. At the short muscle
length, the passive stiffness decreases [100, 101] because
of a smaller stretch of connective tissue, and therefore
the MMG amplitude should increase [102]. However,
for the long length: a high level of muscle stiffness may
restrict the ability of muscle fiber to oscillate, thereby
decreasing MMG amplitude [76, 79, 102–104]. Indeed,
Jaskólska et al. [28] noted bigger MMG amplitude during
relaxation at the short rather than at the long muscle
length, irrespective of muscle function (agonist, synergist,
antagonist). Moreover, the magnitude of the MMG ampli
tude increase was also bigger at a short muscle length but
this increase was different in the biceps brachii (agonist),
brachiradialis (synergist) and triceps brachii muscles.
When considering the effect of joint angle on relaxa
tion an optimal angle (optimal length) is worth noting.
Jaskólska et al. [29] conducted an experiment in which
the optimal angles for maximal isometric force and for
relaxation parameters were determined. The authors
noted that the optimal elbow joint angle at which elbow
flexor muscles produced maximum voluntary force did
not always coincide with the angle at which relaxation
indices had the best result. The optimal muscle length
for relaxation was found for each index of relaxation
separately (the angle at which the rates of relaxation
achieved the highest value and half relaxation time
achieved the lowest value). The average value of the
optimal elbow joint angle for relaxation was almost the
same as for the optimal elbow joint angle for maximum
voluntary force (these angles ranged from 87.9 to 90.9°).
However, for most subjects, the optimal angle for relaxation was 5 or 10° smaller or larger than the optimal
elbow joint angle at which elbow flexor muscles produced maximum voluntary force [29]. It is known that
the maximum voluntary force is obtained at an optimal
length, because of the greatest number of cross-bridges
available to generate force at that length. Probably also
the influence of the muscle length on the Ca2+ affinity
of the myosin ATPase should be taken into account. The
changes in intermyofilament spacing, as a consequence
of changes in muscle length, may be responsible for
the altered cross-bridge kinetics and, therefore, length-dependent changes in Ca2+ sensitivity [105]. As was
already said, the slow phase of relaxation would mainly
depend on the rate of Ca2+ uptake and the fast relaxation
would depend on cross-bridge dissociation rate [20]. If
the individual cross-bridge cycles were independent of
each other, their dissociation rate would be expected to
be independent of the filament overlap. Thus, the optimal
length of maximal voluntary force can be different from
the optimal angle of relaxation. Additionally, during
voluntary contraction of muscle in situ, there are inter-subject differences in joint and muscle-tendon complex
structure and architecture. As a consequence, for each
subject there might be a characteristic joint angle creating
the best conditions for the fastest relaxation.
The results indicate that the optimal angle assessment can be of some importance when studying muscle
length–relaxation relationship.
Relaxation from voluntary contraction
– an effect of age
A factor that may also contribute to the changes in
relaxation speed is age. An example of force–time relationship with a course of relaxation in young and old
female is presented in Figure 4.
In the study at the cellular level analysis of the
transients with a Ca2+ removal model showed that the
143
HUMAN MOVEMENT
Figure 4. Force–time characteristic recorded in old
and young women during maximal voluntary contraction
with a relaxation course on the right side of curves and
force development on the left side of the curves
results are consistent with a relatively larger contribution
of the sarcoplasmic reticulum Ca2+ pump and a lower
expression of myoplasmic Ca2+ buffers in fibers of young
versus old animals [106].
During voluntary relaxation, the speed of late relaxa
tion is dependent on antagonists muscle [28]. Klein et al.
[107] noted a higher level of coactivation (~ 5%) in the
biceps brachii, brachioradialis and triceps brachii muscles in old compared with young men during maximal
isometric contraction of elbow flexion and extension.
Similar results were recorded by Brzenczek [108], who
found a greater co-contraction of antagonists during
elbow flexion and extension in old women compared to
the young. Thus, supposedly the higher level of coactivation in antagonist muscle in the old can affect the late
relaxation. The speed of the early relaxation is dependent
mainly on motor unit derecruitment of agonistic muscles
[28], and at the cellular level, on effectiveness of Ca2+
uptake by the sarcoplasmic reticulum and the speed of
cross-bridge kinetics detachment [10, 109–111]. Taking
into consideration preponderance of ST fibers in old
and the fact that the ST fibers are characterized by a
smaller amount of sarcoplasmic reticulum network and
a slower uptake of calcium ions through the sarcoplasmatic reticulum, a lower speed of early relaxation can
be expected in the old. Moreover, a decrease in Ca2+
ATPase activity and in the rate of Ca2+ movement through the sarcoplasmic reticulum with age [25, 112], also
may cause a lower speed of early relaxation in old. An
additional factor that may contribute to the changes in
144
relaxation speed with age is an age-related change in the
muscle’s connective tissue (e.g. their elastic properties –
stiffness) [113, 114]. If elastic energy is released during
relaxation it may affect relaxation rate [115]. The study
of Adach et al. [116] confirms that the relaxation is slower
in elderly men than in young men. Adach et al. [116]
noted that the relaxation in its entire course gets slower
with age, with the greatest changes during the first half
of relaxation. However, Häkkinen and Häkkinen [117]
did not note significant differences in the time of relaxation among women of different age groups (30 years,
50 years and 70 years). The difference between results
of Adach et al. [116] and Häkkinen and Häkkinen [117]
can be associated with subject’s gender and the tested
muscle (Adach et al. [116] – elbow flexors, Häkkinen
and Häkkinen [117] – leg extensor muscles). Jaskólska
et al. [95] showed that female hormones fluctuations
may have an effect on relaxation speed, especially on
its late phase, while results of Buccolieri et al. [118]
suggest that neural mechanisms contribute differently
to the relaxation of muscles with a different functional
role. However, Häkkinen and Häkkinen [117] noted that
the maximal absolute rate of relaxation was significantly
lower in the oldest group than in the middle or youngest
group. But this difference most probably is related to the
smaller force resulting partly from a bigger antagonist
co-activation in old compared to young subjects.
The present results show that the speed of relaxation
from voluntary contraction slows down with age but the
degree of changes is different in the early and late relaxa
tion from voluntary contraction. Moreover, voluntary
relaxation is dependent on the tested muscle [116–118].
Voluntary relaxation in distal arm muscles is mainly related to the reduction of motor cortical output, while in
proximal muscles a spinal disfacilitation is also present
and possibly sustained by modulation of presynaptic
inhibition [118]. Thus, age-related changes in relaxation
mechanisms need to be analysed separately for the early
and late phase of relaxation in different muscle groups.
Conclusions
The derecruitment strategy during voluntary relaxation includes the reduction of motor unit firing rate and
level of motor unit recruitment. The early phase of volun
tary relaxation executed with slow speeds is governed by
reduction of motor unit firing rate while late relaxation
phase – by reduction of motor unit recruitment level.
During relaxation done with high speed strategy can be
different therefore future studies on motor unit strategy
HUMAN MOVEMENT
during voluntary relaxation executed with different speeds
are required. Since antagonist muscle affects relaxation
speed from voluntary contraction, such a strategy needs
to be assessed in the antagonists as well.
The voluntary muscle relaxation is mediated by
preparatory mechanisms similar to the voluntary muscle
contraction in the contralateral primary motor cortex and
possibly in the bilateral the supplementary motor areas,
but not in the primary negative motor area. In addition,
some functional difference might exist in the bilateral
frontal regions (prefrontal area, supplementary negative
motor areas) between the relaxation and contraction tasks.
However, further studies are necessary to localize the
inhibitory motor centers and to investigate the influence
of the speed of the relaxation and/or the force level on
preparatory mechanisms of relaxation from voluntary
contractions.
The early and late phases of relaxation are differently
affected by joint angle during voluntary contraction,
which is partly related to different changes in EMG
activity of agonist and antagonist muscles, and is accompanied by their different MMG activity.
In addition, both phases slow down with age but the
degree of slowing down is different in the two phases.
The voluntary relaxation mechanisms appeared also to
be dependent on the tested muscle.
Concluding, experiments on relaxation of different
muscle groups executed with varied speeds and from
a different force level with simultaneous recordings of
EMG and MMG signals of agonist and antagonist mus
cles and EEG from the sensorimotor cortex are necessary
to reveal exact mechanisms of voluntary relaxation.
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Paper received by the Editors: July 6, 2005.
Paper accepted for publication: August 30, 2005.
Katarzyna Kisiel-Sajewicz
Katedra Kinezjologii
ul. Rzeźbiarska 4
51-629 Wrocław, Poland
e-mail: kisiel@sreh.awf.wroc.pl
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2)
REGULAMIN PUBLIKOWANIA PRAC
instructions for authors
Redakcja półrocznika Human Movement przyjmuje do
publikacji oryginalne prace empiryczne oraz przeglądowe
dotyczące ruchu człowieka z różnych dziedzin nauki (m.in.
medycyny sportu, fizjologii wysiłku fizycznego, biomechaniki, antropomotoryki, socjologii, psychologii, pedagogiki)
w zakresie wychowania fizycznego, zdrowotnego, rekrea
cji i turystyki, rehabilitacji, fizjoterapii. Przyjmowane są
również listy do Redakcji, sprawozdania z konferencji
naukowych i recenzje książek. Prace mogą być napisane w
języku polskim lub angielskim. Teksty polskie po uzyskaniu
pozytywnej recenzji są tłumaczone na język angielski przez
Redakcję. Autorzy nie otrzymują honorarium.
Warunkiem rozpoczęcia prac redakcyjnych nad artykułem
jest dostarczenie do Redakcji trzech kopii maszynopisu (wydruku komputerowego) przygotowanego zgodnie z niniej
szym regulaminem oraz dyskietki (3 1/2” w formacie IBM)
lub dysku CD-ROM zawierających komplet materiałów. Na
etykiecie dyskietki (CD-ROM-u) należy podać tytuł pracy
oraz numery wersji użytych edytorów i programów graficznych. Praca może być wysłana pocztą elektroniczną
(por. Poczta elektroniczna).
List przewodni i oświadczenie
Do maszynopisu (wydruku komputerowego) autor powi
nien dołączyć list przewodni oraz oświadczenie, że treść
artykułu nie była i nie będzie publikowana w tej formie w
innych wydawnictwach bez zgody Redakcji czasopisma
Human Movement oraz że zgadza się na ogłoszenie jej w
tym półroczniku. W przypadku prac zespołowych oświadczenie może złożyć w imieniu wszystkich współautorów
autor główny.
Ocena pracy (recenzja)
Praca jest recenzowana przez dwie osoby. Autor może
podać nazwiska potencjalnych recenzentów, lecz Redakcja
zastrzega sobie prawo decyzji o ich doborze. Recenzenci nie
znają nazwiska autora ani autor nie zna nazwisk recenzen
tów, dlatego do artykułu należy dołączyć tzw. ślepą stronę,
tzn. tylko z tytułem pracy. W zależności od sugestii osób
oceniających Redakcja podejmuje decyzję o dalszym losie
pracy. Decyzja Redakcji jest ostateczna.
Maszynopis (wydruk komputerowy)
Tekst prac empirycznych wraz ze streszczeniem, rycinami i tabelami nie powinien przekraczać 20 stron, a prac
przeglądowych – 30 stron znormalizowanych formatu A4
(ok. 1800 znaków na stronie, złożonych 12-punktowym
pismem Times New Roman z zachowaniem 1,5 interli-
The Human Movement journal, issued semi-annually,
accepts for publication original papers and review papers
in various aspects of human movement (e.g., sociology,
psychology, pedagogy, exercise physiology, biomechanics,
motor control, sport medicine) in a broad sense of the term:
physical education, recreation, physiotherapy, health and
fitness, and sport science. Authors are not paid for their articles. Letters to the Editor, reports from scientific meetings
and book reviews are also welcome. Articles written in Polish
and English will be accepted. After acceptance, articles in
Polish will be translated into English by the Editorial Office.
Three copies of the manuscript and figures should be
sent to the Editorial Office. If you send the printed version
by e-mail, a floppy disk should be submitted containing
the whole text of the paper. The label of the disk should
include the name of the first author, paper title, as well as
the version numbers of the word processor and graphics
programs used. IBM 3 1/2’’ disks and CD-ROMs are acceptable. It is advisable to use Microsoft Word. Electronic
manuscripts are preferred.
Cover letter
Authors must submit a cover letter with the manuscript.
Each submission packet should include a statement signed
by the first author that the work has not been published
previously or submitted elsewhere for review. It should
also contain Author’s acceptance of Publisher’s terms. The
paper should be accompanied with the correspondence
address of the Author, the telephone number, fax number
and e-mail address.
Review process
Received manuscripts are first examined by the editors
of Human Movement. Incomplete packages or manuscripts
not prepared in the required style will be sent back to authors
without scientific review. Authors are encouraged to suggest the names of possible reviewers, but Human Movement
reserves the right of final selection. Manuscripts will be sent
anonymously to two reviewers. As soon as possible after
the review process is concluded, you will be notified by
e-mail of the acceptance or rejection of your contribution
for publication, our decision is ultimate.
Preparation of the manuscript
Experimental papers should be divided into the following
parts: title page, blind title page, abstract with key words,
introduction, materials and methods, results, discussion,
conclusions, acknowledgements, references. In papers of
149
HUMAN MOVEMENT
Regulamin publikowania prac – Instructions for authors
nii). Redakcja przyjmuje teksty przygotowane wyłącznie
w edytorze tekstu Microsoft Word. Strony powinny być
ponumerowane.
strona tytułowa
Na stronie tytułowej należy podać:
1. Tytuł pracy w języku polskim i angielskim. 2. Skrócony tytuł artykułu w języku angielskim (nie dłuższy niż
40 znaków), który będzie umieszczony w żywej paginie. 3.
Nazwiska autorów z afiliacją. 4. Imię i nazwisko autora(ów)
wraz z adresem do korespondencji, numerem telefonu,
faksu i koniecznie e-mailem.
Kontakt z autorem będzie utrzymywany wyłącznie za
pomocą poczty elektronicznej.
streszczenie
Przed tekstem głównym należy umieścić streszczenie
w języku angielskim, zawierające około 250 wyrazów
i 3–6 słów kluczowych (ze słownika i w stylu MeSH).
Powinno się ono składać z następujących części: Purpose,
Basic procedures, Main findings, Conclusions.
tekst główny
Tekst główny pracy empirycznej powinien zawierać
następujące części: wstęp, materiał i metody, wyniki, dysku
sja (omówienie wyników), wnioski, podziękowania (jeżeli
potrzebne), przypisy (jeżeli występują), piśmiennictwo (zawarte tylko w bazach danych, np. SPORTDiscus, Medline).
W pracach innego typu należy zachować logiczną ciągłość
tekstu, a tytuły poszczególnych jego części powinny odzwierciedlać omawiane w nich zagadnienia.
Wstęp. Należy wprowadzić czytelnika w tematykę
artykułu, opisać cel pracy oraz podać hipotezy oparte na
przeglądzie literatury.
Materiał i metody. Należy dokładnie przedstawić
materiał badawczy (w przypadku osób biorących udział
w eksperymencie podać ich liczebność, wiek, płeć oraz
inne charakterystyczne cechy), omówić warunki, czas i
metody prowadzenia badań oraz opisać wykorzystaną do
nich aparaturę (z podaniem nazwy wytwórni i jej adresu).
Sposób wykonywania pomiarów musi być przedstawiony
na tyle dokładnie, aby inne osoby mogły je powtórzyć. Jeżeli
metoda jest zastosowana pierwszy raz, należy ją opisać
szczególnie precyzyjnie, potwierdzając jej trafność i rzetelność (powtarzalność). Modyfikując uznane już metody,
trzeba omówić, na czym polegają zmiany oraz uzasadnić
konieczność ich wprowadzenia. Gdy w eksperymencie
biorą udział ludzie, konieczne jest uzyskanie zgody komisji etycznej na wykorzystanie w nim zaproponowanych
przez autora metod (do maszynopisu należy dołączyć kopię
odpowiedniego dokumentu). Metody statystyczne powinny
być tak opisane, aby można było bez problemu stwierdzić,
czy są one poprawne. Autor pracy przeglądowej powinien
również podać metody poszukiwania materiałów, metody
selekcji itp.
150
a different type, sections and their titles should refer to the
described issues.
Papers should be submitted in three printed copies or
sent via e-mail. An experimental paper, together with the
figures, tables and abstract, should not exceed 20 pages
(30 pages for a review paper). A normal page is considered
to be an A4 sheet, of 30 lines and 60 characters per line,
with 12-point Times New Roman font, one and half-spaced
text, with margins of 25 mm at the sides and at the top and
bottom. Type or print on only one side of the paper. Use
one and half spacing throughout, including the title page,
abstract, text, acknowledgments, references, tables, and
legends. Number pages consecutively, beginning with the
title page. Put the page number in the upper-right corner
of each page.
title page
The title page should contain: title of the article, name
and surnames of author(s) and their affiliations, name and
address of the author responsible for correspondence about
the manuscript with fax, phone, and e-mail address; and
a short running head of no more than 40 characters (count
letters and spaces).
blind title page. Because reviews are blind, include
a blind title page with only the title.
abstract
The second page should contain the abstract (ca. 250
words). The abstract should be divided into: Purpose, Basic
procedures, Main findings and Conclusions. It should
emphasize any new and important aspects of the study.
Below the abstract, authors should provide (and identify as such) 3 to 6 key words that will assist indexers to
cross-index the article. If suitable MeSH terms are not
yet available for recently introduced terms, present terms
may be used.
text should contain the following sections: Introduc
tion, Material and methods, Results, Discussion, Conclusions,
Acknowledgements (if necessary), References.
Introduction. State the purpose of the article and
summarize the rationale for the study. Give only strictly
pertinent references and do not include data or conclusions
from the work being reported.
Material and methods. Clearly describe selection of the
experimental subjects. Identify their age, sex, and other
important characteristics. Identify the methods, apparatus
(give the manufacturer’s name and address in parentheses),
and procedures in sufficient detail to allow other workers
to reproduce the results. Give references to established
methods, including statistical methods (see below); provide
references and brief descriptions for methods that have been
published but are not well known; describe new or substantially modified methods, give reasons for using them, and
HUMAN MOVEMENT
Wyniki. Przedstawienie wyników powinno być logiczne i spójne oraz powiązane z danymi zamieszczonymi w
tabelach i na rycinach.
Dyskusja (omówienie wyników). Autor powinien odnieść uzyskane wyniki do danych z literatury (innych niż
omówione we wstępie), podkreślając nowe i znaczące
aspekty swojej pracy.
Wnioski. Przedstawiając wnioski, należy pamiętać o
celu pracy oraz postawionych hipotezach, a także unikać
stwierdzeń ogólnikowych i niepopartych wynikami własnych badań. Stawiając nowe hipotezy, trzeba to wyraźnie
zaznaczyć.
Podziękowania. Można wymienić osoby lub instytucje,
które pomogły autorowi w przygotowaniu pracy bądź
wsparły go finansowo lub technicznie.
Piśmiennictwo. Piśmiennictwo należy uporządkować
według kolejności cytowania w tekście, w którym dla oznaczenia odwołania do piśmiennictwa należy posługiwać się
numerami ujętymi w nawiasy kwadratowe, np. Bouchard
et al. [23]. Piśmiennictwo (zawarte tylko w bazach danych,
np. SPORTDiscus, Medline) powinno się składać z nie
więcej niż 30 pozycji, z wyjątkiem prac przeglądowych.
Niewskazane jest cytowanie prac nieopublikowanych.
Przykłady zapisu piśmiennictwa
Powołanie na artykuł z czasopisma [nazwisko autora(ów), inicjał imienia, tytuł artykułu, tytuł czasopisma
w przyjętym skrócie, rok wydania, tom lub numer, strony]:
Shinohara M., Li S., Kang N., Zatsiorsky V.M., Latash
M.L., Effects of age and gender on finger coordination in
MVC and submaximal force-matching tasks. J Appl Physiol,
2003, 94, 259–270.
Gdy autorami artykułu jest sześć lub mniej osób, należy
wymienić wszystkie nazwiska, jeżeli jest ich siedem i więcej,
należy podać sześć pierwszych, a następnie zastosować
skrót „et al.”
Tytuł artykułu w języku innym niż angielski autor
powinien przetłumaczyć na język angielski, a w nawiasie
kwadratowym podać język oryginału. Tytuł czasopisma
należy zostawić w oryginale. W pracy powinny być
uwzględnianie tylko artykuły publikowane ze streszczeniem angielskim: Jaskólska A., Bogucka M., Świstak R.,
Jaskólski A., Mechanisms, symptoms and after-effects of
delayed muscle soreness (DOMS) [in Polish]. Med Sportiva, 2002, 4, 189–201.
Powołanie na książkę [nazwisko autora(ów) lub redaktora(ów), inicjał imienia, tytuł pracy przetłumaczony na
język angielski, wydawca, miejsce i rok wydania]: Osiński
W., Anthropomotoric [in Polish]. AWF, Poznań 2001.
Powołanie na rozdział w książce [nazwisko autora(ów),
inicjał imienia, tytuł rozdziału, nazwisko autora(ów) lub
redaktora(ów), tytuł pracy, wydawca, miejsce i rok wydania,
evaluate their limitations. When reporting experiments on
human subjects, indicate whether the procedures followed
were in accordance with the ethical standards of the responsible committee on human experimentation (institutional
or regional). The Editors reserve the right to reject papers
if there is doubt whether suitable procedures were used.
Describe statistical methods with enough detail to enable
a knowledgeable reader with access to the original data to
verify the reported results. When possible, quantify findings
and present them with appropriate indicators of measurement
error or uncertainty (such as confidence intervals). Authors
submitting a review manuscript should include a section
describing the methods used for locating, selecting, extracting, and synthesizing data. These methods should also be
summarized in the abstract.
Results. Present results in a logical sequence in the
text, tables, and figures. Do not repeat in the text all the
data presented in the tables or illustrations; emphasize or
summarize only important observations.
Discussion. Emphasize the new and important aspects
of the study and the conclusions that follow from them.
Do not repeat in detail data or other material given in the
Introduction or the Results section. Include implications
of the findings and their limitations, including implications
for future research. Relate observations to other relevant
studies.
Conclusions. Link the conclusions with the goals of the
study but avoid unqualified statements and conclusions not
completely supported by the data. Avoid claiming priority
and alluding to work that has not been completed. State new
hypotheses when warranted, but clearly label them as such.
Acknowledgments. List all contributors who do not meet
the criteria for authorship (e.g., a person who provided
purely technical help or writing assistance). Financial and
material support should also be acknowledged.
References. References (only the ones included in international data bases, e.g. SPORTDiscus, Medline etc.)
should be submitted on a separate sheet of paper and in
the order of appearance in the text. References should be
numbered consecutively in the order in which they are first
mentioned in the text. Identify references in text, tables, and
legends by Arabic numerals in parentheses, e.g. Bouchard
et al. [23]. Except in the case of review articles, the total
number of references should not exceed 30.
A journal article should include: surname of the author(s); first name (only initials); title of the paper; title
of the journal in the accepted abbreviation; year, volume
(number), and pages. List all authors when six or less;
when seven or more, list first six and add et al. Example:
Shinohara M., Li S., Kang N., Zatsiorsky V.M., Latash M.L.,
Effects of age and gender on finger coordination in MVC
and submaximal force-matching tasks. J Appl Physiol,
2003, 94, 259–270.
151
HUMAN MOVEMENT
strony]: McKirnan M.D., Froelicher V.F., General principles of exercise testing. In: Skinner J.S. (ed.), Exercise
testing and exercise prescription for special cases. 2nd Ed.
Lea & Febiger, Philadelphia 1993, 3–28.
Powołanie na materiały zjazdowe tylko umieszczane
w międzynarodowych bazach danych, np. SPORTDiscus:
Racz L., Tihanyi J., Hortobagyi T., Muscle fatigue during
concentric and eccentric contraction. In: Avela J., Komi
P.V., Komulainen J. (eds.), Proceedings of the 5th Annual
Congress of the European College of Sport Science. July
19–23, 2000, Jyvaskyla Finland, 600.
Powołanie na artykuły w formie elektronicznej: Dons
mark M., Langfort J., Ploug T., Holm C., Enevoldsen
L.H., Stallknech B. et al., Hormone-sensitive lipase (HSL)
expression and regulation by epinephrine and exercise in
skeletal muscle. Eur J Sport Sci, Volume 2, Issue 6 (December 2002). Available from: URL: http://www.humankinetics.
com/ejss/bissues.cfm/
Przypisy. Przypisy, objaśniające lub uzupełniające tekst,
powinny być numerowane z zachowaniem ciągłości w całej
pracy i umieszczone na końcu tekstu głównego.
Tabele i ryciny. Tabele i ryciny wraz z numeracją, podpisami oraz opisami należy umieścić na osobnych stronach,
na których odwrocie trzeba podać tylko tytuł pracy, bez
nazwiska autora. Jeżeli w tekście nie ma powołania na tabelę lub rycinę, należy zaznaczyć miejsce jej umieszczenia.
Ryciny muszą być czarno-białe lub w odcieniach szarości.
Symbole, np. strzałki, gwiazdki, lub skróty należy dokładnie objaśnić w legendzie. Wykresy powinny być wykonane
w programach Excel lub Statistica 5.0 i dołączone jako
osobne pliki w formacie *.xls lub *.stg. Pozostałe ryciny
(np. schematy) należy przygotować w programie Corel
Draw (wersja 8 lub niższa) i dołączyć jako osobne pliki w
formacie *.cdr. Fotografie lub inne materiały ilustracyjne
można dostarczyć w formie elektronicznej (*.tif, *.jpg –
gęstość punktów obrazu 300 lub 600 dpi) bądź w postaci
nadającej się do ostatecznego opracowania przez Redakcję.
Nie można powtarzać tych samych wyników w tabelach
i na rycinach.
Praca, w której tabele i ryciny będą przygotowane niezgod
nie z podanymi wymogami, zostanie odesłana do autora.
Korekta autorska
Artykuł po opracowaniu redakcyjnym zostanie przekazany do autora w celu naniesienia przez niego korekty
autorskiej. Obowiązkiem autora jest odesłanie korekty
w ciągu jednego tygodnia. Kosztami poprawek innych niż
drukarskie będzie obciążony autor.
Poczta elektroniczna
Zachęcamy autorów do przesyłania prac w postaci
elektronicznej (jako załączniki). Każda część pracy powinna
być przesłana jako oddzielny załącznik: plik tekstowy, plik
152
Articles not in English: Authors should translate the title
into English and enclose the language of translation in square
brackets. Do not translate the title of the journal. Only
papers with English abstracts should be cited. Example:
Jaskólska A., Bogucka M., Świstak R., Jaskólski A., Mechanisms, symptoms and after-effects of delayed muscle soreness (DOMS) [in Polish]. Med Sportiva, 2002, 4, 189–201.
A book should include: the author’s or editor’s surname (authors’ or editors’ surnames), first name initials, the
title of the book in English, publisher’s name, place and
year of publication. Example: Osiński W., Anthropomotoric
[in Polish]. AWF, Poznań 2001.
Chapter in a book: McKirnan M.D., Froelicher V.F.,
General principles of exercise testing. In: Skinner J.S. (ed.),
Exercise testing and exercise prescription for special cases,
2nd Ed. Lea & Febiger, Philadelphia 1993, 3–28.
Conference proceedings and papers can only be referred to in the text if they are included in international data
bases, e.g. SPORTDiscus. Example: Racz L., Tihanyi J.,
Hortobagyi T., Muscle fatigue during concentric and eccentric
contraction. In: Avela J., Komi P.V., Komulainen J. (eds.),
Proceedings of the 5th Annual Congress of the European
College of Sport Science. July 19–23 2000, Jyvaskyla
Finland, 600.
Article in electronic form. Example: Donsmark M.,
Langfort J., Ploug T., Holm C., Enevoldsen L.H., Stallknech B. et al., Hormone-sensitive lipase (HSL) expression
and regulation by epinephrine and exercise in skeletal
muscle. Eur J Sport Sci, Volume 2, Issue 6 (December
2002). Available from: URL: http://www.humankinetics.
com/ejss/bissues.cfm/
Tables and figures. Each table together with its number,
title, and annotations, should be submitted on a separate
sheet of paper. Authors should identify the places where
tables and figures are to be included within the text. Figures
should be prepared in black and white and marked on the
back with the title of paper only (do not include the name
of the author). Legends for the figures should be submitted
on a separate sheet of paper and should be self-explanatory.
When symbols, arrows, numbers, or letters are used to
identify parts of the illustrations, identify and explain each
one clearly in the legend. Only Figures prepared in Excel,
Statistica 5.0 or Corel Chart (version 8 or lower) will be
accepted. The recommended file formats for figures are:
*.jpg, *.tif, with an image resolution of 300 or 600 dpi.
Figures and tables should be numbered consecutively
according to the order in which they have been first cited
in the text. Data should not be repeated in tables and figures.
Photographs must be black and white glossy prints.
Proofs
The corresponding author will receive one proof. Only
minor corrections can be made at this time. Corrections
other than printing errors may be charged to the author. It
HUMAN MOVEMENT
z rycinami, plik z tabelami, plik fotograficzny itd. Aby przy
spieszyć przesyłkę, pliki należy skompresować w postaci
*.arj lub *.zip. Komplet plików powinien być przesłany na
adres hum_mov@awf.wroc.pl
Prawa Redakcji
Redakcja zastrzega sobie prawo poprawiania usterek
stylistycznych oraz dokonywania skrótów. Prace przygotowane niezgodnie z regulaminem będą odsyłane autorom
do poprawy.
Prawa autorskie
Publikacje podlegają prawu autorskiemu wynikającemu
z Konwencji Berneńskiej i z Międzynarodowej Konwencji
Praw Autorskich, poza wyjątkami dopuszczanymi przez
prawo krajowe. Żadna część publikacji nie może być reprodukowana, archiwizowana ani przekazywana w jakiejkolwiek
formie ani żadnymi środkami bez pozwolenia właściciela
praw autorskich.
Płatna reklama
Redakcja przyjmuje zamówienia na reklamy, które mogą
być umieszczane na 2. i 3. stronie okładki lub na dodatkowych kartach sąsiadujących z okładką. Ceny reklam będą
negocjowane indywidualnie.
is the author’s responsibility to return the corrected proofs
within 1 week.
Sending via email
Authors who have an access to Internet are encouraged
to send their work-files electronically using standard E-Mail
software. The E-mail software must have an option to send
data files attached to the E-Mail message. In such cases,
all parts of the work should be sent as a separate files: text
file, picture file(s), table file(s), photo file(s). To speed up
the data transfer, files should be compressed (if possible)
using *.arj or *.zip formats before transmission. Complete
packages of manuscripts are to be sent to the following
address: hum_mov@awf.wroc.pl
Reprints
Each Author will receive 1 copy of the issue in which
his/her work appears.
Advertising
The Editorial Board accepts advertising orders. Advertisements can be published on the second and third page of
the cover or on the pages next to the cover. Advertisement
prices will be negotiated individually.
153
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2005, vol. 6 (2)
University School of Physical Education in Wrocław
Department and Institute of Swimming organize
The 3nd International Symposium
Factors Determining the Efficiency
of Swimming Training and
the Learning-Teaching Process
25–27 May 2006
The main purpose of the meeting will be to exchange the latest
research findings, to discuss new ideas and to initiate new
projects in the area of swimming science and related sciences.
Address
Katedra i Zakład Pływania
al. I.J. Paderewskiego 35
e-mail: piotr.albinski@awf.wroc.pl
jaszczak@awf.wroc.pl
www.awf.wroc.pl/swim
University School of Physical Education in Wrocław
and Popular Knowledge Society’s Lower Silesian
University College of Education in Wrocław organize
An International Scientific Conference
Psychomotorics movement
FULL OF MEANING
26–27 October 2006
The understanding of psychomotorics as a holistic concept
gives the opportunity of a full perception of a person. There
is a place in it for every theory and practice connected with
the support of the development and creative presence of
children, the youth and adults, the healthy and disabled, the
lost and the searching their own path.
Address
Katedra Humanistycznych Podstaw Kultury Fizycznej
al. I.J. Paderewskiego 35
„Konferencja Psychomotoryka 2006”
e-mail: konferencja.psychomotoryki@awf.wroc.pl
www.awf.wroc.pl
Zasady prenumeraty czasopisma Human Movement
The rules of subscribing the Human Movement journal
Cena rocznej prenumeraty (dwa numery) dla odbiorców
indywidualnych w kraju wynosi 27 zł, dla instytucji 55 zł. Dla
odbiorców indywidualnych za granicą wynosi 27 eu, dla instytucji 55 eu.
Numery czasopisma wysyłamy pocztą po otrzymaniu odpowiedniej wpłaty na konto:
BPH PBK S.A. O/Wrocław
18 1060 0076 0000 3200 0040 0409
al. Paderewskiego 35, 51-612 Wrocław,
z dopiskiem: Prenumerata Human Movement.
Prosimy zamawiających o bardzo wyraźne podawanie adresów,
pod które należy wysyłać zamawiane egzemplarze czasopisma.
Pojedyncze egzemplarze można zamówić, wpłacając 16 zł
(odbiorca indywidualny) i 30 zł (instytucja) na podane konto
i wpisując numer oraz liczbę zamawianych egzemplarzy na
odwrocie blankietu wpłaty (odcinek dla posiadacza rachunku).
Pojedyncze numery można zakupić w cenie 16 zł w punktach
sprzedaży książek w AWF we Wrocławiu oraz AWF w Warszawie.
Dla odbiorców z Europy Wschodniej zachowujemy taką samą
cenę jak dla odbiorców w Polsce, przeliczając złote na walutę
kraju docelowego po kursie w dniu zamawiania.
154
The price of annual subscription (two issues) for individual
foreign subscribers is Euro 27 and Euro 55 for foreign institutions.
The issues of the journal are sent by post after receiving the
appropriate transfer to the account:
BPH PBK S.A. O/Wrocław
18 1060 0076 0000 3200 0040 0409
al. Paderewskiego 35, 51-612 Wrocław, Poland,
with the note: Human Movement subscription.
We ask the subscribers to give correct and clearly written
addresses to which the journal is to be sent.
Single copies can be ordered by transferring Euro 16 (individual foreign subscribers) and Euro 30 (foreign institutions) to
the above mentioned account and writing in the number and the
amount of issues ordered at the back side of the form.
Single copies of the journal outlets are available at the University School of Physical Education in Wrocław and Warszaw.
For the recipients from Eastern Europe the price is the same as
for Poland, and the price is converted to the currency of a given
country on the day of ordering.
HUMAN
MOVEMENT
HUMAN
MOVEMENT
2005, vol. 6 (2)
International Council for Physical Activity
and Fitness Research
University School of Physical Education
in Wrocław
24th International Council for Physical Activity
and Fitness Research Symposium
PHYSICAL ACTIVITY
AND FITNESS RESEARCH: NEW HORIZONS
9–11 September 2006, Wrocław, POLAND
International Scientific Committee
Prof. F. Viviani, Italy, ICPAFR President Prof. A.L. Claessens, Belgium, Co-Chairman
Prof. T. Koszczyc, Poland, Co-Chairman Prof. G. Doll-Tepper, Germany
Prof. A. Hills, Australia Prof. Z. Ignasiak, Poland
In 1964, the International Committee for the Standardization
of Physical Fitness Tests (ICSPFT) was founded in Tokyo,
Japan, by a group of researchers in sports medicine, anthropometry, physiology of exercise and physical education, led
by Prof. Leonard A. Larson, USA. The standardization process
culminated in the publication of a book on standards of physical
fitness tests in 1974.
This was the result of 9 years of work including 6 international
seminars and comparative research in many countries around
the world which aimed at the standardization of the tests. In
1973, in Jyväskylä, Finland a decision was made to change
Prof. T. Jurimae, Estonia
Prof. W. Osiński, Poland
Prof. A. Rutkowska-Kucharska, Poland
Prof. M. Woźniewski, Poland
S. Czyż, Ph.D., Poland
the name of the Committee to the International Council for
Physical Fitness Research (ICPFR), and in 1992, in Leuven,
Belgium to the International Council of Physical Activity and
Fitness Research (ICPAFR). Since its foundation, the organization has held 20 international seminars and symposia in
different countries.
For detailed information visit:
www.awf.wroc.pl/icpafr
Contact: Stanisław Czyż, czysta@awf.wroc.pl
Aging and Physical Activity 2006
Application to Fitness, Sport and Health
and
14th Conference “Physical Education and Sport in Scientific Researches”
International Scientific Conference
Rydzyna, Poland
15–17 September 2006
The Conference will provide the latest scientific knowledge
and offers for discussion and the exchange of both ideas
and experience in the controversial issues aging, physical
activity, physical fitness and health.
CONFERENCE TOPICS
Exercise and biology of aging.
Physical activity and health of older people.
Exercise prescription and training programs for the elderly.
Biomechanical perspective of exercise in old age.
Daily functioning and exercise.
Demographic and biological aspects of aging.
Economic and social consequences of an aging society.
Free topics (poster sessions only)
Organisers
University School of Physical Education in Poznań
State School of Higher Vocational Education in Leszno
Patronage
International Association of Sport Kinetics
Committee of Rehabilitation, Physical Culture and Social
Integration of Polish Academy of Science
Contact: dr Janusz Maciaszek
Zakład Teorii Wychowania Fizycznego i Antropomotoryki
ul. Królowej Jadwigi 27/39
61-871 Poznań, Poland
e-mail: osinski@awf.poznan.pl
www.konferencje.pwsz.edu.pl
155

University School of Physical education in Wrocław University

Transcription

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