XXXIII FIMS World Congress of Sports Medicine
Transcription
XXXIII FIMS World Congress of Sports Medicine
XXXIII FIMS World Congress of Sports Medicine – From Prevention to Performance Quebec City, QC CANADA June 18 -‐21 2014 Concurrent Symposia: Symposia II Thursday June 19 2014, 1400 – 1530 H Presenters: Dr. Erika Persson, Dr. Lyle Micheli and Agnes Makowski Moderator: Dr. Laura Cruz Truth and Myths in Pediatric Sports Medicine Erika B Persson MD FRCPC Dip Sport Med Pediatric Sport Medicine Glen Sather Sports Medicine Clinic epersson@ualberta.ca ¡ Faculty: Dr. Erika B Persson ¡ Relationships with commercial interests: § Not applicable ¡ This program has no commercial support ¡ Not Applicable ¡ By the end of this session the attendee will: § Have a better understanding of the pediatric skeleton including the growth plate and its vulnerability for injury § Recognize features of overtraining and burnout in child and adolescent athletes § Increase awareness of youth sport development with a focus on issues with early specialization § Be able to advocate for enjoyable, safe and injury reduced youth sport “Child Athletes Are Just Mini Adult Athletes” TRUTH or MYTH “Child Athletes Are Resilient and Cannot Be Overtrained or Suffer Burnout” TRUTH or MYTH “The Earlier the Better – Specialization” TRUTH or MYTH http://www.dailymail.co.uk/femail/article-‐2535246/Dont-‐look-‐like-‐circus-‐people-‐Verne-‐Troyer-‐abandons-‐Mini-‐Me-‐make-‐TV-‐series-‐realities-‐living-‐ dwarfism.html Epiphysis and epiphyseal plate (“physis”) occur in individuals < 20 yrs of age and are essential for bone development Pressure Physis ¡ Located end of long bones and responsible for longitudinal growth and circumferential bony remodeling ¡ Injury è loading related § Separation of physeal plate § Physeal widening § Salter Harris fracture patterns Traction Physis – “apophysis” ¡ Located on long bones at site of tendon insertion of specific muscle ¡ Weak link in kinetic chain § Less so as ossification occurs with age ¡ ¡ Site of secondary ossification Injury è traction related § Acute avulsion § Chronic traction causing protuberance/irritation Epiphysis Reserve zone Proliferative zone Hypertrophic zone Metaphysis Slide Courtesy of Dr. S Dulai Epiphysis Reserve Zone § Resting cartilage § Stem cells divide to produce chondrocytes § Matrix production § **Vessels do not pass through this zone Metaphysis Slide Courtesy of Dr. S Dulai Epiphysis Proliferative Zone § Chondrocytes divide rapidly § Cells arranged in longitudinal columns § Continued matrix production Metaphysis Slide Courtesy of Dr. S Dulai Epiphysis Hypertrophic Zone § Maturation zone ▪ Mature chondrocytes produce collagen matrix ▪ Cells increase in volume (producing longitudinal growth) § Degenerative Zone ▪ Cells begin to degenerate and begin producing chondrocalcin to prepare the cartilage for mineralization § Zone of Provisional Calcification Metaphysis ▪ Cells continue to hypertrophy and eventually die when they reach the end of the growth plate ▪ Cartilage matrix is calcified Slide Courtesy of Dr. S Dulai n Epiphyseal and metaphyseal blood supplies do NOT communicate with one another à INCREASED RISK OF AVASCULAR NECROSIS (AVN) From: Brighton CT: Structure and function of the growth plate. Clin Orthop 136:23-32, 1978 Slide Courtesy of Dr. S Dulai ¡ ¡ “injury to the physis/apophysis due to chronic repetitive trauma” Specific injuries occur when the physis is open and vulnerable – age specific § i.e. Sever’s presenting in preadolescents vs. iliac crest apophysitis in mid adolescents ¡ Injury mechanism: § Repetitive muscular contraction with insufficient recovery time ▪ Adults = chronic tendinous injury ▪ Youth = apophysitis § The developing growth region is not permitted to undergo normal stress related adaptation and remodeling ▪ Mechanical load > Remodeling capacity ¡ Histologically see abnormal endochondral ossification with increased osteoblastic activity; edema; chondrocyte, spindle cell and small vessel proliferation; diminished metaphyseal perfusion and minimal inflammatory cell infiltration § Can result in growth disturbance, physeal widening and occasionally bony bridging ¡ Anatomic areas at risk often depend on sport and activity type § Upper extremity apophyses affected in swimming and throwing/racquet sports § Lower extremity apophyses affected in running and cutting/pivoting sports ¡ Commonly seen during periods of rapid growth § 11-‐12 yrs in girls and 13-‐14 yrs in boys ¡ Underlying abnormalities in bone development make growth plate even more vulnerable § i.e. osteomyelitis, scurvy, rickets, endocrinopathies ¡ ¡ Complaints of pain over affected apophysis/physis that is increased with passive stretching or active contraction of associated muscle groups Chronic course with gradual onset, relieved by relative rest and then resurgence of symptoms with return to sport/activity § Sets stage for ongoing pressure/traction and lack of recovery time Figure 7. Gymnast’s wrist: stress injury to the distal radial physis in an 11-year-old female gymnast complaining of wrist pain. (a) Anteroposterior radiograph of the wrist shows widening of the distal radial physis (arrow). MR imaging was performed 3 months later because of persistent pain. (b) Coronal GRE MR image shows irregularity and focal widening (arrow) of the physeal cartilage that extends into the metaphysis. (c) Follow-up anteroposterior radiograph radiographics.rsna.org Figure 6. Little Leaguer’s shoulder: chronic physeal injury to the proxima 10-year-old male pitcher. (a) Anteroposterior radiograph of the shoulder sh the proximal humeral physis. Because of persistent pain and concern for a g formed. (b) Coronal oblique T1-weighted MR image also shows a wide irre MR image shows a broad band of increased signal intensity (arrowhead), a No tear of the glenoid labrum was depicted. March-April 2012 ¡ Imaging (if done) may show irregularity, fragmentation, widening or sclerosis of the physis Treatment includes relative rest, addressing muscular deficits in control, strength and flexibility, reducing traction on apophysis (if possible) 542 ¡ 2' s 6OLUME .UMBER From: Jaimes C: Taking the Stress out of Evaluating Stress Injuries in Children. RadioGraphics 2012; 32:537-‐555 ¡ ¡ ¡ ¡ ¡ ¡ ¡ More cartilage and collagen than in fully ossified adult bones Weaker chondro-‐osseous junctions Narrower bones with thinner cortex Increasing bone mineral content and density with growth Increased blood supply and thicker periosteum = faster recovery and potential for remodeling Weaker bones vs. tendons/ ligaments è more fracture vs. ligament injury Less resistant to tensile, shear and compressive forces during periods of rapid growth ¡ ¡ ¡ ¡ ¡ Increased pliability of bone = risk for torsion style fracture Growing cartilage susceptible to repetitive loading and injury Reduced incidence of non-‐union and joint stiffness Altered biomechanics of limb during growth – mass, length, moment of inertia With adolescent growth spurt can see reduced flexibility, coordination and balance § Girls – Start at 10 yrs; peak at 12 yrs § Boys – Start at 12 yrs; peak at 14 yrs ¡ Pediatric athletes are still developing § § § § ¡ Increased energy and nutritional requirements in youth athletes § ¡ Gross motor skills, cognitive skills, emotional regulation Impact ability to safely participate in sport and perform required skills Basics of running, jumping and throwing With developing cognitive ability may not be able to recognize early signs of injury Need to fuel activity AND metabolic demands for normal growth and development Increased risk for certain training issues: § Heat illness(*controversial) ▪ Increased surface to body mass ratio, reduced heat dissipation capability, temperature and humidity effects, level and awareness of hydration status ¡ Strength Training § Is a safe practice and youth DO have ability to alter muscular strength and gain muscle mass ▪ Does not disrupt linear growth or damage growth plates ▪ Proper and supervised technique, lower weight and more repetitions and avoid Olympic style weightlifting ▪ Can be injury protective ¡ Cardiovascular Fitness § Youth can achieve a training effect on VO2max with regular endurance work ▪ Lost with sedentary behavior “Child Athletes Are Just Mini Adult Athletes” TRUTH or MYTH “Child Athletes Are Resilient and Cannot Be Overtrained or Suffer Burnout” TRUTH or MYTH http://abcnews.go.com/meta/search/imageDetail?format=plain&source=http://abcnews.go.com/images/International/gty_china_training_weights_kb_ss_120808 Many benefits of regular sport participation: ¡ ¡ ¡ ¡ Increased cardiovascular fitness Reduced obesity rates Improved bone health and BMD Improved academic performance ¡ ¡ ¡ ¡ ¡ Reduced mental health dysfunction Higher self esteem Higher family satisfaction levels Less risk taking behaviors Reduced risk of disease in adulthood However when a youth athlete has “too much of a good thing”…….see increased injury rates and risk of harm from sport prevention in this population. TABLE 1. Potential Risk Factors for Injury in Child and Adolescent Sport Extrinsic Risk Factors Intrinsic Risk Factors Nonmodifiable Nonmodifiable Sport played (contact/no contact) Previous injury Level of play (recreational/elite) Other Factors to CAge onsider Position played Sexintensity Workload – hours, volume, Coaching Style and Experience Weather Time of season/time of day Other Athletes Potentially Modifiable Competition Schedules Fitness level Pressures (Self, Parent, Coach) Potentially modifiable Preparticipation sport-specific Lack of Periodization Rules training Playing time Flexibility Playing surface (type/condition) Strength Equipment (protective/footwear) Joint stability Biomechanics ¡ ¡ ¡ Physical representation of overtraining Account for approx. 50% of all youth sport injury “microtraumatic damage to a bone, muscle or tendon that has been subjected to (submaximal) repetitive stress without sufficient time to heal or undergo the natural reparative process” – Brenner 2007 4 Stages: 1. Pain after physical activity 2. Pain during activity, without restricting performance 3. Pain during activity that restricts performance 4. Chronic, unremitting pain even at rest 3 Situations: 1. Rapid increase in training after inactivity or reduced activity level 2. Participation level exceeds skill level 3. Consistent activity at exceptionally high level ¡ Performance of excessive amounts of high-‐intensity, repetitive physical activity without adequate rest or break ¡ “Overtraining” § Set of symptoms including fatigue, sleep disturbances, chronic muscle and joint pain, elevated resting HR, reduced sport performance, mood disturbance (reduced attention, irritability, depression), reduced academic performance ▪ May see HPA axis disturbance = Cortisol, GH, prolactin, ACTH ¡ “Burnout” § Chronic stress leading to athlete to stop participating in a previously enjoyable sport § On spectrum of overreaching and overtraining § Maladaptive state in athlete – reduced mood and vigor, depression, anger, fatigue, confusion, tension, lack of enthusiasm for sport, difficulty completing usual life routine ¡ ¡ Larger psychological component in youth vs. adults Seen more in females, individual sports, athletes competing at highest level for their sport ¡ Seeing increased rates of youth affected § Practice, conditioning and competition programs are becoming more and more like adult and professional ¡ With higher training loads and intensity we see reports of increased injury – overuse and traumatic § 2.6 million/year ER visits in US for youth sport injury (2001-‐2003) § More injuries seen during practice vs. competition § Increasing injury rates not proportionate to increasing participation rates ¡ Seeing more youth training year round in multiple sports with NO off-‐ season § Parents and coaches and athletes often unaware of the risks of this intense activity level ¡ Sport specific reports of ‘forced early retirement’ with strong associations to sustaining an overuse injury or overtraining/burnout § Australian track and field athletes – Huxley 2014 ¡ Lack of evidence based rules and guidelines to outline ‘safe’ youth sport training principles § Some sport specific guidelines exist ▪ i.e. pitch counts in Little League Baseball ¡ Overall, little to recommend or enforce to those involved in youth sport and concerned about safety How much activity is enough for health promotion? How much activity is too much leading to harm? ¡ § Dearth of research looking at these questions ¡ Winning as ultimate goal vs. Having fun and being active § Overvaluing of success may be resultant of youth sports being modeled after adult sport ¡ Who’s dream is it?…….child vs. parent California, 1920 Colorado Ave, Santa Monica, CA 90404, USA; jdifiori@mednet.ucla.edu Accepted 2 December 2013 Taxonomy (SORT) grading system. Definition of overuse injury Overuse injuries occur due to repetitive su mal loading of the musculoskeletal system ¡ Recent publication: rest is not adequate to allow for structural tion to take place. Injury can involve the Consensus statement tendon unit, bone, bursa, neurovascular str To cite: DiFiori JP,Overuse injuriesand andthe burnout in youth sports: injuries unique to physis. Overuse Benjamin HJ, Brenner JS, a position statement frominclude the American Medical injuries and et al. Br J Sports Med athletes apophyseal Medicine 2014;48:287–288.Society for Sports stress injuries. Downloaded from bjsm.bmj.com on April 1, 2014 - Published by group.bmj.com Editor’s choice Scan to access more free content John P DiFiori,1 Holly J Benjamin,2 Joel S Brenner,3 Andrew Gregory,4 Neeru Jayanthi,5 Greg L Landry,6 Anthony Luke7 to space Epidemiology DiFiori▸onlyDue JP, et constraints al. Br JBackground Sports Med 2014;48:287–288. doi:10.1136/bjsports-2013-093299 the Executive Summary is published in the print journal. To read the complete Consensus statement, please visit the journal online (http:// dx.doi.org/10.1136/bjsports2013-093299). Youth sport participation offers many benefits including the development of self-esteem, peer socialisation and general fitness. However, an emphasis on competitive success, often driven by goals of elite-level travel team selection, collegiate scholarships, Olympic and National team membership and even professional contracts, has seemingly become widespread. This has resulted in an increased pressure to begin high-intensity training at young ages. Such an excessive focus on early intensive training and competition at young ages rather than skill development can lead to overuse injury and burnout. It is estimated that 27 million US youth between 6 and 18 years of age participate in team sports. The National Council of Youth Sports survey found that 60 million children aged 6–18 years participate in some form of organised athletics, with 44 million participating in more than one sport. There is very little research specifically on the incidence and prevalence of overuse injuries in children and adolescents. Overall estimates of overuse injuries versus acute injuries range from 45.9% to 54%. The prevalence of overuse injury varies by the specific sport, ranging from 37% (skiing and handball) to 68% (running). Overuse injuries are underestimated in the literature because most of the epidemiological studies define injury as requiring a time loss from participation. ¡ Systematic review of the evidence on overuse injuries and burnout in youth sports to help clinicians recognize, treat and prevent 1 Division of Sports Medicine and Non-Operative Orthopaedics, Departments of Family Medicine and Orthopaedics, University of California, Los Angeles, California, USA 2 Departments of Pediatrics and Orthopaedic Surgery, University of Chicago, Chicago, Illinois, USA 3 Department of Pediatrics, Purpose ¡ Environment: § § § § § § § ¡ Personal Characteristics § § § § § § ¡ Extremely high training volumes Extremely high time demands Demanding performance expectations (self or others) Frequent intense competition Inconsistent coaching practices Little personal control in sport decision making Negative performance evaluations (critical vs. supportive) Perfectionism Need to please others Non-‐assertiveness One-‐dimensional self-‐conceptualization (‘athlete = self’) Low self-‐esteem High Anxiety Early Sport Specialization From: DiFiori JP. Overuse injuries and burnout in youth sports: a position statement from the AMSSM. 2014 g Box 3 Diagnosis of overtraining syndrome/ burnout180 208 by self or ad of supportive) only on one’s aching was found –188 One-third of experienced overent of adolescent History Decreased performance persisting despite weeks to months of recovery Disturbances in mood Lack of signs/symptoms or diagnosis of other possible causes of underperformance Lack of enjoyment participating in sport Inadequate nutritional and hydration intake Presence of potential triggers: (a) increased training load with adequate recovery, (b) monotony of training, (c) excessive number of competitions, (d) sleep disturbance, (e) stressors in family life ( parental pressure), (f ) stressors in sporting life (coaching pressure and travel demands), (g) previous illness. Testing (if indicated by history) Consider laboratory studies: complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate, C reactive protein, iron studies, creatine kinase, thyroid studies, cytomegalovirus and Epstein-Barr virus titres. Profile of Mood States (POMS): a psychometric tool for a global measure of mood, tension, depression, anger, vigour, fatigue and confusion.179 From: DiFiori JP. Overuse injuries and burnout in youth sports: a position statement from the AMSSM. 2014 1. Keep workouts interesting with age appropriate games and training, to keep practice fun ¡ 2. Take time off from organized/structured sport participation 1 to 2 days per week to allow the body to rest and participate in other activities ¡ 3. Permit longer scheduled breaks from training and competition every 2 to 3 months while focusing on other activities and cross training to prevent loss of skill or level of conditioning ¡ 4. Focus on wellness and teaching athletes to be in tune with their bodies for cues to slow down or alter their training methods ¡ From: Brenner JS. Overuse Injuries, Overtraining, and Burnout in Child and Adolescent Athletes. Pediatrics 2007 “Child Athletes Are Just Mini Adult Athletes” TRUTH or MYTH “Child Athletes Are Resilient and Cannot Be Overtrained or Suffer Burnout” TRUTH or MYTH “The Earlier the Better – Specialization” TRUTH or MYTH http://www.newyorker.com/online/blogs/sportingscene/2013/07/genetics-‐searching-‐for-‐the-‐perfect-‐athlete.html ¡ Belief that there is a high chance for a talented youth athlete to become elite and achieve high levels of success if they work hard enough and start young § § § § § ¡ Parents Athletes Coaches Sport Organizations Sport Industry Reports of child prodigy athletes making headline news § National and international recognition, financial rewards and other perceived benefits of elite status § E.g. Tiger Woods and Andre Agassi ¡ The numbers tell a different story…… (Q10 yr) tracks from novice to elite status were identified among senior national Australian athletes. Compared with athletes on the ‘‘slow’’ trajectory, those on the ‘‘quick’’ path began their main sport at a later age (17.1 T 4.5 vs 7.9 T Social Isolation Focus on a single sport and the associated time commitment may foster isolation from age and sex peers, especially TABLE 2. Estimated percentages of athletes moving from high school to college, high school to professional, and college to professional in several sports in the United States.a Men’s Sports Basketball Football Baseball Ice Hockey Soccer Women’s Basketball Total 549,500 983,600 455,300 29,900 321,400 456,900 Seniors 157,000 281,000 130,100 8500 91,800 130,500 4500 16,200 7300 1100 5200 4100 High school athletes College freshman athletes High school to college, % 2.9 5.8 5.6 12.9 5.7 3.1 College athletes Total Seniors Athletes drafted 15,700 56,500 25,700 3700 18,200 14,400 3500 12,600 5700 800 4100 3200 44 250 600 33 76 32 College to professional, % 1.3 2.0 High school to professional, % 0.03 0.09 10.5 0.46 4.1 1.9 1.0 0.39 0.08 0.02 a Adapted from the National Collegiate Athletic Association (47), percentages are based on estimated data and thus are approximations. Estimates for the professional level are based on athletes drafted; there is no guarantee that they qualified for the playing roster. Volume 9 Number 6 November/December 2010 c c Early Sport Specialization Copyright @ 2010 Lippincott Williams & Wilkins. Unauthorized of thisSpecialization: article is prohibited. From: Malina reproduction RM: Early Sport Roots, 367 Effectiveness, Risks. Curr. Sports Med. Rep. 2010; 9:6:364-‐371 98% of young athletes will NEVER reach elite status – Merkel 2013 ¡ Many studies exist demonstrating early age sport performance excellence does not translate to adult sport excellence nor predict success as an adult athlete in that sport ¡ § Due to many factors in physical, emotional, cognitive and psychological development ¡ Then why do we see this pressure…… § Future (unrealistic) hopes for social, financial, educational rewards by athletes, families, coaches, sport organizations, society ¡ The concept of stages and progression of normal growth and development can be applied to sport development/readiness § Match of domain development with demands of specific sport § Is individual to each child and occurs on a spectrum § Gross motor skills often highlighted however must not forget about cognitive development § Mismatching sport participation and skill development can precipitate stress, anxiety and possibly attrition § Pre Participation Exams offer excellent opportunity for assessing sport readiness § Suggested team sports be introduced after 6 yrs of age – developmental readiness to participate safely at this age ¡ Unfortunately many coaches who are involved with youth programs do not have formal training in pediatric sport issues and thus may have unrealistic expectations for their youth athletes § 8% of US High School coaches have formal coaching training § Conflicting research on injury risk as it relates to coaching experience and training § Coaching style and training may possibly contribute to early sport attrition From Purcell L. Sport readiness in children and youth . Paediatr Child Health 2005 ¡ Seeing increasing numbers of very young athletes participating year round in ONE sport – world wide and multiple sports: § § ¡ ¡ ¡ Pressure from parents, coaches and sport programs to “make it big” Best way to produce super athletes is to play one sport from an early age and play continuously – commonly believed myth of parents, coaches and kids Roots in misinterpretation of Communist Eastern European programs in mid to late 20th century enrolling very young children in sports academies § § § ¡ Travel/Select teams – soccer, baseball, basketball, football Callaway Junior World Golf Championships – youngest age division = 6 and under! Immigrating coaching and sport science staff brought (mis)concept to the West Lack evidence basis Skewed success perceptions -‐ focus on few sports, unique situations, training issues i.e. doping Very few sports ‘require’ this method of training § Figure skating, Diving, Gymnastics, Dance – early entry sports ▪ Achieve highest success level and elite status during adolescence ¡ For the majority of sports, individuals who reach elite status often start training at older ages and have a varied cross training program or background which permits skill transfer ¡ Research into early sport specialization and its impact on the growing athlete is in its infancy however we are starting to see potential evidence for: § Development of anti-‐social behaviors ▪ Lack of cooperation ▪ Social isolation ▪ Arrested behavioral development § § § § Overdependence Burnout and Overtraining Injury Mental Health Issues ▪ Anxiety, depression, altered self identity § Family Stress ▪ Financial and interpersonal relationships § § § § Less time participating at the elite level Early retirement from sports Child is now ‘merchandise’ for sale to commercial enterprises Increased potential for abuse ¡ Few and far between, however those that do reach elite status: § Have dedicated practice ▪ >10,000 hrs. to excel at a skill or 10 years – extrapolation to sport from arts and music expertise research § Internal love of the sport allowing high volume of training and competition § Highly motivated and have ability to sustain highs and lows of sport participation § Family environment that is child centered with parents that are very involved in youth’s activity and family has emphasis and value on achievement ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ Delay sport specialization until 12-‐13 yrs of age to allow diverse skill development 1 – 2 days of rest per week Take 2-‐3 months off of specific sport to allow recovery Participation on one team per sport per season Limit training volume increases to 10% per week Adjust scheduling of competition/training to allow rest between sessions Monitoring of physical and emotional symptoms that may indicate overuse injury, overtraining and burnout Sports should be for fun, sportsmanship, safety and skill acquisition NOT competition Encourage education around safe training and competition environments to parents, coaches and sport organizations ¡ Let’s play! § Encourage free play and cross training for enjoyment ¡ Increase awareness of normal sport development in youth § Coaching and sport development programs should be based on these principles ¡ ¡ Focus on technique and correct movement patterns instead of time and volume Let kids be kids! § Not the next 6 yr. old child prodigy § Sport participation should be child focused and driven and not directed by adult pressures to achieve unrealistic goals ¡ We need more data……….what is really occurring in the youth athletes of the 21st Century!!!! ¡ After attending this session the attendee will now: § Better understand of the pediatric skeleton including the growth plate and its vulnerability for injury § Recognize features of overtraining and burnout in child and adolescent athletes § Be aware of youth sport development with a focus on issues with early specialization § Advocate for enjoyable, safe and injury reduced youth sport Let’s wait until we see what Dr. Micheli and Agnes have to tell us……. ¡ ¡ ¡ ¡ ¡ ¡ ¡ Arnaiz J et al. Imaging findings of lower limb apophysitis. AJR March 2011, 196: W316-‐W325 Jaimes C et al. Taking the stress out of evaluating stress injuries in children. RadioGraphics March-‐April 2012, 32:537-‐555 Huxley DJ et al. An examination of the training profiles and injuries in elite youth track and field athletes. European Journal of Sport Science 2014, 14;2: 185-‐192 Merkel DL. Youth sport: positive and negative impact on young athletes. Open Access Journal of Sport Medicine 2013, 4: 151-‐160 Bergeron MF. The young athlete: challenges of growth, development, and society. Curr. Sports Med. Rep., 2010, 9;6:356-‐358 Merkel DL, Molony JT. Recognition and management of traumatic sports injuries in the skeletally immature athlete. International Journal of Sports Physical Therapy, Dec 2012, 7;6:691-‐704 Carter CW, Micheli LJ. Training the child athlete for prevention, health promotion and performance: how much is enough, how much is too much? Clin Sports Med 2011, 30: 679-‐690 ¡ ¡ ¡ ¡ ¡ ¡ ¡ Emery CA. Risk factors for injury in child and adolescent sport: A systematic review of the literature. Clin J Sport Med 2003, 13: 256-‐268 Paterno MV et al. Prevention of overuse sport injuries in the young athlete. Orthop Clin N Am 2013, 44:553-‐564 Barton L. Overuse injuries and burnout in youth sports: what we know and what we don’t. http://www.momsteam.com/health-‐safety/overuse-‐injuries-‐burnout-‐ in-‐youth-‐sports-‐what-‐we-‐know-‐what-‐we-‐don’t. Accessed May 10 2014. DiFiori JP et al. Overuse injuries and burnout in youth sports: a position statement from the American Medical Society for Sports Medicine. Br J Sports Med Apr 2014, 48: 287-‐288 DiFiori JP. Evaluation of overuse injuries in children and adolescents. Curr. Sports Med Rep. 2010, 9:6:372-‐378 Luke A et al. Sports-‐related injuries in youth athletes: is overscheduling a risk factor? Clin J Sport Med 2011, 21:307-‐314 International Olympic Committee. IOC Consensus statement on training the elite child athlete. ¡ ¡ ¡ ¡ ¡ ¡ ¡ Malina RM. Early sport specialization: roots, effectiveness, risks. Curr. Sports Med. Rep. 2010, 9;6:364-‐371 Farrey T. Competitive youth sports in society: what President Obama needs to know and get – and keep – kids moving. Curr. Sports Med. Rep. 2010, 9;6:359-‐363 Brenner JS. Overuse injuries, overtraining and burnout in child and adolescent athletes. Pediatrics June 2007, 119;6: 1242-‐1245 Purcell L. Sport readiness in children and youth. Paediatr Child Health July/Aug 2005, 10;6: 343-‐344 Seto CK et al. Pediatric running injuries. Clin Sports Med 2010, 29:499-‐511 Hall R et al. Sports specialization is associated with an increased risk of developing anterior knee pain in adolescent female athletes. J Sport Rehab 2014 in press http://dx.doi.org/10.1123/jsr.2013-‐0101 Stracciolini A et al. Pediatric sports injuries: An age comparison of children versus adolescents. Am J Sports Med 2013, 41; 8: 1922-‐1929