Since the publication of landmark works by Astrand (2) and Robinson (45) during the middle of the last century, interest in the study of pediatric exercise science by medical, fitness, and sport organizations has grown exponentially (5,8,30). Although much of what we understand about the stimulus of exercise has been gained by exploring the effects of different training protocols on adults, current findings indicate that regular participation in exercise and sport programs offers observable health, fitness, and performance value to children and adolescents (10,47,55). In addition to enhancing selected measures of aerobic and anaerobic fitness, daily physical activity can improve metabolic health, enhance cognitive function, foster socialization, and spark an ongoing interest in exercise and sport as a lifestyle choice (18,19).
At present, global health recommendations suggest that children and adolescents should accumulate at least 60 minutes of moderate to vigorous physical activity (MVPA) daily in the context of family, school, and community activities (55). Yet, epidemiological data indicate that most children and adolescents worldwide are not meeting physical activity recommendations, and cardiovascular disease risk factors such as obesity, dyslipidemia, and hypertension are present in inactive youth (21,23,55). Furthermore, troubling trends in early sports specialization and overuse injuries among young athletes are a growing concern among sports medicine professionals (8,25). Consequently, public health policies and long-term interventions that prepare children and adolescents for a lifetime of physical activity are needed.
Just like the skills of reading and writing, physical activity is a learned behavior that is influenced by family, friends, teachers, and coaches. With proper guidance, skilled instruction, and ongoing support, youth can learn the technical and tactical aspects of exercise and sport while making friends, having fun, and learning something new. Thus, the science of pediatric exercise needs to be balanced with the “art” of coaching kids, which is the glue that holds it all together. Our updated “coach's dozen” is a list of 12 principles that build on our years of experience teaching and coaching youth (12). The list is not meant to be definitive or complete, but rather a collection of related ideas that youth coaches, physical education teachers, and pediatric exercise specialists should think about. For ease of discussion, we broadly define the word “coach” to include all professionals who work with children and adolescents in exercise and sport programs. The terms youth and young athletes refer to both children and adolescents.
BUILD A STRENGTH RESERVE
The enduring impact of structured resistance training on health-, fitness-, and performance-related variables continues to be advanced by researchers and practitioners (11,28,47). Leading professional organizations within the fields of physical education, sport science, and pediatric medicine support participation in youth resistance training programs that are developmentally appropriate, technique-driven, and supervised by qualified fitness professionals (31). New insights into the design of youth fitness programs continue to highlight the importance of resistance training for enhancing athletic performance and reducing injury risk (10,26,28). Integrative training programs that include resistance exercise have been found to elicit significant improvements in muscular strength, power production, running velocity, dynamic balance, and sport-specific performance (10,28,37). From an injury prevention perspective, exercise interventions that include resistance training have been found to reduce sports-related injuries by one-third and overuse injuries by almost 50% (26).
Regular participation in youth resistance training can build a strength reserve for sustainable participation in exercise and sport throughout the growing years (28,32). Stronger young athletes will be better prepared to learn complex movements, withstand the demands of sports practice and competition, and achieve a level of physical performance which is needed for long-term sport success (10,26). In light of secular trends which illustrate relatively low levels of muscular fitness in modern-day youth (11), an integrative approach to training which includes resistance exercise, will help to fill the critical need for modern-day youth to build their strength reserve and reduce their risk of activity-related injuries (37).
Conventionally, the term dynapenia has been used to describe the age-related loss of muscle strength in older adults that increases the risk of functional limitations and mortality (6). In our view, the term “pediatric dynapenia” should be used to describe poor levels of muscular strength in youth not caused by disease and the consequent risk for movement limitations and activity-related injury. The use of this term can be used to raise awareness about the importance of planned resistance training for children and adolescents. Without developmentally appropriate interventions that target muscle weakness early in life, the divergence in performance between youth with low and high levels of muscular fitness will likely persist into adolescence. Consequently, relatively weaker boys and girls may be unwilling and perhaps unable to catch up with their peers who possess higher levels of strength and motor skill ability (39,46). School-based physical education taught by trained specialists has proven to be an ideal setting for enhancing muscular strength in children (9,14,35).
DEVELOP MOVEMENT SKILL COMPETENCY
The term movement skill competency refers to the technical ability of properly performing the critical elements of a specific exercise or skill with style, grace, and precision. An instructional climate that develops movement skill competency early in life will set the stage for more advanced training strategies later in life. Youth who become proficient in fundamental movement skills early in life are more likely to participate in physical activities and find sport participation more enjoyable than youth with low motor competence (1,13,46). Because motor performance skills are essential components of sport movements, there is a critical need during childhood to develop, reinforce, and ingrain desired motor patterns into the movement skill vocabulary of children and adolescents (36).
The development of movement skill competency is a step-wise process, and youth must demonstrate mastery of a basic skill under the guidance of a qualified coach before progressing to the next level. Although the “quantity” of the training performance (i.e., how much weight was lifted) must be monitored, it is equally important to provide specific feedback on the “quality” of the movement. This type of “process” assessment involves the evaluation of movement patterns that are considered essential for mastery of a particular exercise (3). Youth coaches should regularly assess movement skill competency and provide participants with specific feedback regarding the technical performance of every exercise. In addition, participants should be cognizant of expected behaviors and should demonstrate a genuine commitment to improving exercise performance. This approach to coaching can provide youth with the knowledge, skills, and understanding that are needed to become aware of technical flaws and improve performance. Over time, complex movements will become “automatic” and consequently require less conscious thought.
TRAIN THE DEVELOPING BRAIN
Regular exposure to free play and planned training early in life will set the stage for even greater gains in physical fitness later in life, provided the games and activities are consistent with the needs, abilities, and interests of the participants (11,46). Although there is no evidence-based minimum age for participation in a structured training program, youth should be able to follow instructions and handle the demands of an exercise program. Although participants as young as 5 and 6 years of age participate in sport programs, an age of 7–8 years is when most youth are ready for some type of structured conditioning including resistance training (31). Conceptually, youth who are not exposed to skill-based training early in life may not be able to capitalize on the high degree of neuromuscular plasticity during this developmental period. Of note, meta-analytical findings indicate that children make greater gains in motor performance skills than adolescents after resistance training (4), and that exercise interventions designed to prevent sports injuries are more effective when performed earlier in life (43).
The ability to properly execute complex movements requires the coordinated integration of cognitive, sensory, emotional, perceptual, and motor control subsystems that evolve during childhood (38). Brain development during the growing years likely corresponds to this developmental period when these subsystems are developing optimally, and therefore, children can learn complex skills (e.g., weightlifting and plyometric movements) at an earlier age more efficiently than older populations because they can use developing pathways that control coordination, control and proficiency (34). Owing to the neuromuscular plasticity of the developing brain, there is a unique opportunity to target the development of muscular fitness and motor skill proficiency early in life to enhance the performance of more advanced movements and athletic abilities later in life (38).
These observations support a potential synergistic adaptation whereby training-induced gains in performance during childhood and adolescence complement naturally occurring adaptations (10). Although most children can learn basic movements (e.g., running, jumping, and squatting), their ability to perform more complex movements later in life will be influenced by their exposure to training programs early in life that address neuromuscular deficiencies, reinforce desired movement patterns, and target specific outcomes. Without opportunities to train their developing brain, youth will experience greater difficulty performing basic movement skills and will not be able to build on an existing framework of physical fitness.
BECOME PHYSICALLY LITERATE
The concept of physical literacy describes an individual's motivation, confidence, competence, knowledge, and understanding to engage in a variety of physical activities as an ongoing lifestyle choice (54). Physical literacy has become an important term that is used to support the holistic development of youth by encompassing the psychomotor, cognitive, and affective domains of learning (48). As such, the importance of daily MVPA needs to be balanced with effective pedagogy so participants learn how to move properly and begin to take responsibility for their own actions.
However, it is a misperception to believe that youth will become physically literate without instruction from qualified coaches and regular participation in structured training programs. Youth need education, guidance, and encouragement to gain confidence and competence in their physical abilities, language skills, and musical talents. Without regular opportunities to learn task-related activities and perform physical movements with proper technique in a progressively challenging environment, youth are less likely to become physically literate. Although it is important to study the impact of physical literacy on MVPA, this term does not replace the critical importance of qualified coaches who design, implement, and teach exercise and sport to youth. Evidence-based action taught by qualified coaches and supported within the family, school and community structure is more likely to result in long-lasting participation in exercise and sport than an academic term.
VALUE DELIBERATE PREPARATION
Current research evidence highlights the significant impact of preparatory conditioning on physical preparation and sports injury reduction in young athletes (28,49,50). Youth with muscular imbalances and neuromuscular deficiencies are unwilling and at times unable to perform desired exercises or sport-specific movement patterns. The observable impact of modern-day lifestyles on muscular fitness and motor skill prowess has increased the need to better prepare aspiring young athletes for the demands of sports practice and competition. Of note, reports indicate that youth sport practice may not provide a sufficient amount of MVPA to meet daily recommendations because a large proportion of the time is spent in sedentary or light activities (17,27).
Notwithstanding the value of unstructured free play, deliberate preparation characterized by qualified instruction and a systematic progression of training loads and exercises is needed to improve the preparedness of young athletes for the demands of sports practice and competition (10,28,51). Participation in organized youth sports alone does not ensure that young athletes will attain a level of muscular fitness that will optimize skill performance and prevent the accrual of neuromuscular deficiencies that increase injury risk. A child's participation in sport should not start with competition but rather evolve out of deliberate preparation which addresses individual weaknesses and areas in need of improvement.
Although the total elimination of sports-related injuries is an unrealistic goal, a strategy that focuses on enhancing muscular strength could significantly reduce sports-related injuries in youth athletes (26,52,56). Along with delayed sport specialization, regular participation in a integrative and progressive conditioning program can enhance the readiness of players for sport by increasing muscular strength and boosting tissue tolerance (15,41). The prescription of developmentally appropriate training methods that enhance muscular strength and improve movement mechanics is fundamental to the scope and practice of developing healthy, capable, and resilient young athletes (5,10).
DIVERSIFY THE PORTFOLIO
Broad-based participation in a variety of sport activities during childhood is related more to adolescent physical activity and fitness than early sports specialization (25,41). Exposure to different sport activities during childhood seems to decrease the risk of musculoskeletal disorders which are more often associated with single sport participation (40). Aspiring young athletes should have an opportunity to participate in a variety of exercise and sport activities in different settings so they can discover what they enjoy while maximizing their physical and psychosocial development. Although technical sports such as gymnastics and figure skating typically require early exposure, elite-level success in team sports and endurance sports is often characterized by multisport exposure during the growing years (25,41).
When children participate in a single sport at the exclusion of other sports, they may not develop the repertoire of movement skills that are needed for injury prevention. Moreover, constant practice sessions along with the demands of competition may not allow adequate time for physical and psychological recovery from repetitive stress. Emerging data indicate that injury risk increases if the weekly volume of organized sport training exceeds 16 hours per week or if the hours per week of organized sports is greater than the young athletes' age (40). Although many athletes recover from sports-related injuries, others do not return to their pre-injury level of performance for a variety of physical and psychological reasons (8). Parents and coaches have a responsibility to monitor young athletes regularly for signs and symptoms of stress intolerance (44). If the stress of training and competition is too excessive, untoward consequences including injury, illness, and burnout are possible (8).
UNDERSTAND THE PROCESS
Coaching is a process that is grounded in effective pedagogy and supported by science. Although youth programs should provide an opportunity for all participants to engage in physically challenging and mentally engaging games and activities, the quality of the experience must also be considered. This is where the art and science of coaching comes into play because the physical demands of training must be balanced with effective pedagogy to enhance a child's emotional, social, and cognitive well-being. Effective youth coaches understand the process of coaching and recognize the importance of providing meaningful instruction in a supportive and encouraging environment to inspire participants, enhance physical development, and optimize performance (16). In short, the best coaches are the best teachers who understand how their players learn best.
Children and adolescents who participate in fitness and sport activities with qualified coaches are more likely to optimize training adaptations and experience the mere enjoyment of sport play. Successful coaches are good listeners and exceptional communicators who help participants become aware of their mistakes. Substitute coaches tend to have a very difficult time managing a group of young athletes and inspiring them to achieve personal goals. Additionally, inadequate supervision and inappropriate coaching (e.g., unrealistic progression of training loads) are potentially injurious (42).
Although there is not one coaching model that will enhance athleticism in all participants, the systematic progression of program variables and level-headed support from parents will influence the outcome of youth programs. The most important motives for youth are to develop and demonstrate physical competence, gain social acceptance and support, and have fun. Success should not be measured by the level at which one coaches, but rather by one's ability to help all youth learn from their mistakes, reflect on their experiences, and feel good about their accomplishments.
Creativity refers to the imagination and ingenuity that can help to optimize training-induced adaptations, enhance exercise adherence, and improve athletic performance. By sensibly incorporating novel exercises and new training ideas into fitness programs, coaches can help participants overcome barriers and maintain interest in exercise and sport. When appropriate, participants can create new exercises which contribute to a mastery-oriented climate as they control the type of task engagement and overcome challenges that are self-determined. For example, youth can create new strength-building exercises with medicine balls, develop novel skill-building games with balloons, or find creative solutions to challenging tasks that require speed and agility (i.e., a modified game of tag). Creative thinking is particularly valuable when designing exercise programs for youth with special needs or those with previous sport experience.
There is some evidence that creative thinking may be declining in children and therefore, efforts to encourage creativity in youth sport programs are needed to reclaim opportunities for young athletes to use their imagination, collaborate with peers, and release their creative energy (22). Combining developmentally appropriate training activities with creative instruction from qualified coaches is likely to yield the highest physical, cognitive, and affective benefits for children and adolescents. Coaches should reflect on past experiences and use creative thinking to facilitate the development of training programs that are innovative and challenging. By taking time to reflect on the design and implementation of training programs, coaches can fuel their creativity to generate answers to challenging situations and optimizing training adaptations.
BE PATIENT IN YOUR PRACTICE
Some coaches look for quick fixes and advance youth too quickly through exercise progressions and sport programs. Sustained participation in exercise and sport is built on a solid foundation of general preparation (5,10,29). Patience is needed to wisely progress children and adolescents through exercise and sport programs while avoiding the latest fads and gimmicks. Although it may be tempting to introduce advanced techniques and specialized tactics into developmental programs, children should have regular opportunities to develop their movement vocabulary and reinforce basic movement patterns before progressing to complex skills (36).
Coaches should recognize individual differences and should realize that 2 players with the same chronological age may differ significantly in their biological age and training experience (33). Progression should be “earned” and based on a participant's skill, proficiency, disposition, and understanding of the game. Unfortunately, the pressure to win in some youth programs seems to supersede the development of healthy, strong, and resilient players. Although teaching youth how to win (and lose) is valuable, developing young players who are properly prepared for the enduring demands of sports training and competition is more important in the long run.
Coaches should resist pressure from others to progress players too quickly to set a personal best or experience short-term success. Patience is needed to refine technical errors and develop fundamental movement skills. Without this type of coaching, it is unlikely that youth will maintain a high level of injury-free performance later in life. This failure can be seen at the college and professional levels when elite-level athletes must “relearn” basic exercise patterns. Proper progression during the developmental years will have an observable impact on performance later in life. Coaching, characterized by an impatient progression of exercises and training loads, will limit a player's long-term performance.
ENJOY THE GAME
Although exercise and sport should provide an opportunity for participants to engage in activities that are physically challenging and mentally engaging, the enjoyment of the game should also be considered. Children cite “fun” as the number one reason for participation in organized sport and its absence as the number one reason for attrition from sport (53). A primary goal of any youth exercise or sport program should be to holistically improve fitness performance while promoting welfare and well-being in a safe and fun environment (44).
The principle of enjoyment states that youth who genuinely enjoy exercising are more likely to adhere to the exercise program and achieve training goals. Although encouragement from youth coaches and support from family and friends can influence exercise habits, the enjoyment an individual feels during and after an exercise session can facilitate the sustainability of the desired behavior. Exercise programs should be challenging, yet youth should have the competence and confidence in their physical abilities to perform the exercises or activities with energy and vigor. If the exercise program is too advanced, youth will be anxious and will lose interest. Conversely, if the exercise program is too easy, then youth will become bored. As such, enjoyment can be defined as a balance between skill and challenge (7). Youth exercise and sport programs should be matched with the physical and mental abilities of the participants for the training experience to be enjoyable.
A growing number of modern-day youth are not as active as they should be, and the decline in daily physical activity seems to emerge early in life (20,24). Physical activity is a learned behavior and therefore, children and adolescents should grow up in an environment with regular opportunities to gain confidence and competence in their physical abilities. Without a long-term approach to physical development, youth will be less likely to develop the prerequisite muscle strength and motor skill prowess that is needed for ongoing participation in a variety of sports and activities with energy, interest, and vigor. A long-term physical development plan is an important strategy for enhancing the health, fitness, and sports performance of all children and adolescents (29,36).
The impact of physical inactivity during the growing years on lifelong pathological processes (e.g., obesity and diabetes) and associated health care costs has created a need to think long-term. Likewise, aspiring young athletes need to develop the required skills and enhance their perceived abilities early in life to prevent the development of risk factors and pathological processes later in life. Long-term physical development models, characterized by qualified instruction throughout the early phases, can be used to educate parents, coaches, and sport administrators about appropriate pathways that enhance the holistic development of all youth (29,44). The importance of this issue requires a change in the current way of thinking because there are no short cuts to long-term physical development or elite-level athletic success.
Youth are less mature than adults, and therefore adult training programs (e.g., metabolic training with limited recovery) and ideologies (e.g., “no pain, no gain”) are inappropriate and potentially injurious for younger populations. Clearly, if the pleiotropic benefits of daily physical activity and sports participation early in life are to be realized later in life, exercise and sport programs for youth must be developmentally appropriate, enjoyable, and consistent with the individual needs and abilities of each participant. Although new insights into the development of athletic potential in youth address physical and psychosocial parameters (29), innovative and comprehensive strategies in school (e.g., physical education) and community (e.g., youth sport) programs are needed to ensure that all youth benefit from long-term interventions.
The best youth coaches never stop learning and asking questions about youth fitness, sport science, and effective coaching strategies. By reading journals, attending conferences, and networking with their colleagues, coaches will begin to see things from another perspective. It is likely that within a group, there will be those who have already experienced current events. This provides an opportunity to learn from others and avoid some of the common pitfalls they experienced in the past. By nurturing professional networks and interacting with others in the field, coaches can build a reputation as a knowledgeable, thoughtful, and an informed individual.
Developing healthy, strong, and resilient young athletes takes a lot of time and drive, so it is beneficial to have a network of friends and colleagues to share ideas, ask questions, and receive feedback. By surrounding yourself with people who share similar interests and goals, you are more likely to move forward as a group. Suboptimal coaches often refuse to learn from others, change old habits, or teach skills in different ways. Although it is important to be weary of quick fixes and spurious claims on social media, networking with coaches, researchers, and health care providers can be beneficial for learning, discovery, and sharing ideas.
Being a coach with a willingness to work with children and adolescents is not enough. Youth coaches need to learn from their own experiences, stay up to date with evidence-based practice, and network with other professionals. The most successful coaches are lifelong learners who are willing to try new methods and learn from others in the field. Our coach's dozen provides a framework of ideas that can help coaches build healthy, strong, and resilient young athletes.
1. Aaltonen S, Latvala A, Rose R, Pulkkinen L, Kujala U, Kaprio J, Silventoinen K. Motor development and physical activity: A longitudinal discordant twin-pair study. Med Sci Sports Exerc 47: 2111–2118, 2015.
2. Astrand P. Experimental Studies of Physical Working Capacity in Relation to Sex and Age. Copenhagen, Denmark: Musksgaard, 1952.
3. Barnett L, Reynolds J, Faigenbaum A, Smith J, Harries S, Lubans D. Rater agreement of a test battery designed to assess adolescents' resistance training
skill competency. J Sci Med Sport 18: 72–76, 2015.
4. Behringer M, Vom Heede A, Matthews M, Mester J. Effects of strength training on motor performance skills in children
and adolescents: A meta-analysis. Pediatr Exer Sci 23: 186–206, 2011.
5. Bergeron M, Mountjoy M, Armstrong N, Chia M, Côté J, Emery C, Faigenbaum A, Hall G, Kriemler S, Léglise M, Malina R, Pensgaard A, Sanchez A, Soligard T, Sundgot-Borgen J, van Mechelen W, Weissensteiner J, Engebretsen L. International Olympic Committee consensus statement on youth athletic development. Br J Sports Med 49: 843–851, 2015.
6. Clark B, Manini T. What is dynapenia? Nutrition 28: 495–503, 2012.
7. Csikszentmihalyi M, Abuhamdeh S, Nakamura J. Flow. In: Handbook of Competence and Motivation. Elliot A, ed. New York, NY: The Guilford Press, 2005. pp. 598–698.
8. Difiori J, Benjamin H, Brenner J, Gregory A, Jayanthi N, Landry G, Luke A. Overuse injuries and burnout in youth sports: A position statement from the American Medical Society for sports medicine. Clin J Sports Med 24: 3–20, 2014.
9. Faigenbaum A, Bush J, McLoone R, Kreckel M, Farrell A, Ratamess N, Kang J. Benefits of strength and skill based training during primary school physical education. J Strength Cond Res 29: 1255–1262, 2015.
10. Faigenbaum A, Lloyd R, MacDonald J, Myer G. Citius, Altius, Fortius: Beneficial effects of resistance training
for young athletes: Narrative review. Br J Sports Med 50: 3–7, 2016.
11. Faigenbaum A, Lloyd R, Myer G. Youth resistance training
: Past practices, new perspectives and future directions. Pediatr Exer Sci 25: 591–604, 2013.
12. Faigenbaum A, Meadors L. A coaches dozen: 12 FUNdamental principles for building young and healthy athletes. Strength Cond J 32: 99–101, 2010.
13. Fransen J, Deprez D, Pion J, Tallir I, D'Hondt E, Vaeyens R, Lenoir M, Philippaerts R. Changes in physical fitness and sports participation among children
with different levels of motor competence: A 2-year longitudinal study. Pediatr Exerc Sci 26: 1–21, 2014.
14. Fritz J, Rosengren B, Dencker M, Karlsson C, Karlsson M. A seven-year physical activity intervention for children
increased gains in bone mass and muscle strength. Acta Paediatr 105: 1216–1224, 2016.
15. Gabbett T. The training-injury prevention paradox: Should athletes be training smarter and harder? Br J Sports Med 50: 273–280, 2016.
16. González L, García-Merita M, Castillo I, Balaguer I. Young athletes' perceptions of coach behaviors and their implications on their well- and ill-being over time. J Strength Cond Res 30: 1147–1154, 2016.
17. Guagliano J, Rosenkranz R, Kolt G. Girls' physical activity levels during organized sports in Australia. Med Sci Sports Exerc 45: 116–122, 2013.
18. Institute of Medicine. Educating the Student Body: Taking Physical Activity and Physical Education to School. Washington, DC: The National Academies Press, 2013.
19. Institute of Medicine. Physical Activity: Moving toward Obesity Solutions. Washington, DC: National Academies Press, 2015.
20. Katzmarzyk P, Barreira T, Broyles S, Champagne C, Chaput J, Fogelholm M, Hu G, Johnson W, Kuriyan R, Kurpad A, Lambert E, Maher C, Maia J, Matsudo V, Olds T, Onywera V, Sarmiento O, Standage M, Tremblay M, Tudor-Locke C, Zhao P, Church T. Physical activity, sedentary time, and obesity in an international sample of children
. Med Sci Sports Exerc 47: 2062–2069, 2015.
21. Katzmarzyk P, Barreira T, Broyles S, Champagne C, Chaput J, Fogelholm M, Hu G, Johnson W, Kuriyan R, Kurpad A, Lambert E, Maher C, Maia J, Matsudo V, Olds T, Onywera V, Sarmiento O, Standage M, Tremblay M, Tudor-Locke C, Zhao P, Church T. Physical activity, sedentary time, and obesity in an international sample of children
. Med Sci Sports 47: 2062–2069, 2015.
22. Kim K. The creativity crisis: The decrease in creative thinking scores on the Torrance Tests of creative thinking. Creativity Res J 23: 285–295, 2011.
23. Kit B, Kuklina E, Carroll M, Ostchega Y, Freedman D, Ogden C. Prevalence of and trends in dyslipidemia and blood pressure among US children
and adolescents, 1999–2012. JAMA Pediatr 169: 272–279, 2015.
24. Konstabel K, Veidebaum T, Verbestel V, Moreno L, Bammann K, Tornaritis M, Eiben G, Molnár D, Siani A, Sprengeler O, Wirsik N, Ahrens W, Pitsiladis Y. Objectively measured physical activity in European children
: The IDEFICS study. Int J Obes (Lond) 38: S135–S143, 2014.
25. LaPrade R, Agel J, Baker J, Brenner J, Cordasco F, Côté J, Engebretsen L, Feeley B, Gould D, Hainline B, Hewett T, Jayanthi N, Kocher M, Myer G, Nissen C, Philippon M, Provencher M. AOSSM early sport specialization consensus statement. Orthop J Sports Med 4: 1–8, 2016.
26. Lauersen J, Bertelsen D, Andersen L. The effectiveness of exercise interventions to prevent sports injuries: A systematic review and meta-analysis of randomised controlled trials. Br J Sports Med 48: 871–877, 2014.
27. Leek D, Carlson J, Cain K, Henrichon S, Rosenberg D, Patrick K, Sallis JF. Physical activity during youth sports practices. Arch Pediatr Adolesc Med 165: 294–299, 2010.
28. Lesinski M, Prieske O, Granacher U. Effects and dose–response relationships of resistance training
on physical performance in youth athletes: A systematic review and meta-analysis. Br J Sports Med 50: 781–795, 2016.
29. Lloyd R, Cronin J, Faigenbaum A, Haff G, Howard R, Kraemer W, Micheli L, Myer G, Oliver J. The National Strength and Conditioning Association position statement on long-term athletic development. J Strength Cond ResPress 30: 1491–1509, 2016.
30. Lloyd R, Faigenbaum A, Stone M, Oliver J, Jeffreys I, Moody J, Brewer C, Pierce K, McCambridge T, Howard R, Herrington L, Hainline B, Micheli L, Jaques R, Kraemer W, McBride M, Best T, Chu D, Alvar B, Myer G. Position statement on youth resistance training
: The 2014 international consensus. Br J Sports Med 48: 498–505, 2014.
31. Lloyd R, Faigenbaum A, Stone M, Oliver J, Jeffreys I, Moody J, Brewer C, Pierce K, Myer G. Position statement on youth resistance training
: The 2014 international consensus. Br J Sports Med, 48: 498–505, 2014.
32. Lloyd R, Oliver J, Faigenbaum A, Howard R, De Ste Croix M, Williams C, Best T, Alvar B, Micheli L, Thomas D, Hatfield D, Cronin J, Myer G. Long-term athletic development-Part 1: A pathway for all youth. J Strength Cond Res 29: 1439–1450, 2015.
33. Lloyd R, Oliver J, Faigenbaum A, Myer G, De Ste Croix M. Chronological age versus biological maturation: Implications for exercise programming in youth. J Strength Cond Res 28: 1454–1464, 2014.
34. Lloyd R, Radnor J, De Ste Croix M, Cronin J, Oliver J. Changes in sprint and jump performance following traditional, plyometric and combined resistance training
in male youth pre- and post-peak height velocity. J Strength Cond Res 30: 1239–1247, 2015.
35. Löfgren B, Daly R, Nilsson J, Dencker M, Karlsson M. An increase in school-based physical education increases muscle strength in children
. Med Sci Sports Exerc 45: 997–1003, 2013.
36. Meadors L. Practical application for long-term athletic development. Available at: www.nsca.com
. Accessed February 18, 2016.
37. Myer G, Faigenbaum A, Chu D, Falkel J, Ford K, Best T, Hewett T. Integrative training for children
and adolescents: Techniques and practices for reducing sports-related injuries and enhancing athletic performance. Phys Sportsmed 39: 74–84, 2011.
38. Myer G, Faigenbaum A, Edwards E, Clark J, Best T, Sallis R. 60 minutes of what? A developing brain perspective for activation children
with an integrative approach. Br J Sports Med 49: 1510–1516, 2015.
39. Myer G, Faigenbaum A, Ford K, Best T, Bergeron M, Hewett T. When to initiate integrative neuromuscular training to reduce sports-related injuries and enhance health in youth? Curr Sports Med Rep 10: 155–166, 2011.
40. Myer G, Jayanthi N, DiFiori J, Faigenbaum A, Kiefer A, Logerstedt D, Micheli L. Sport specialization, part I: Does early sports specialization increase negative outcomes and reduce the opportunity for success in young athletes? Sports Health 7: 437–442, 2015.
41. Myer G, Jayanthi N, DiFiori J, Faigenbaum A, Kiefer A, Logerstedt D, Micheli L. Sports specialization, Part II: Alternative solutions to early sport specialization in youth athletes. Sports Health 8: 65–73, 2015.
42. Myer G, Quatman C, Khoury J, Wall E, Hewett T. Youth vs. adult “weightlifting” injuries presented to United States Emergency Rooms: Accidental vs. non-accidental injury mechanisms. J Strength Cond Res 23: 2054–2060, 2009.
43. Myer G, Sugimoto D, Thomas S, Hewett T. The influence of age on the effectiveness of neuromuscular training to reduce anterior cruciate ligament injuries in female athletes: A meta analysis. Am J Sports Med 41: 203–215, 2013.
44. Oliver J, Lloyd J, Meyers R. Training elite child athletes: Promoting welfare and well-being. Strength Cond J 33: 73–79, 2011.
45. Robinson S. Experimental studies of physical fitness in relation to age. Arbeitspyasiologie 10: 251–323, 1938.
46. Robinson L, Stodden D, Barnett L, Lopes V, Logan S, Rodrigues L, D'Hondt E. Motor competence and its effect on positive developmental trajectories of health. Sports Med 45: 1273–1284, 2015.
47. Smith J, Eather N, Morgan P, Plotnikoff R, Faigenbaum A, Lubans D. The health benefits of muscular fitness for children
and adolescents: A systematic review and meta-analysis. Sports Med 44: 1209–1223, 2014.
48. Society of Health and Physical Educators. National Standards & Grade Level Outcomes for K-12 Physical Education. Champaign, IL: Human Kinetics Publishers, 2014.
49. Soomro N, Sanders R, Hackett D, Hubka T, Ebrahimi S, Freeston J, Cobley S. The efficacy of injury prevention programs in adolescent team sports: A meta-analysis. Am J Sports Med 44: 2415–2424, 2016.
50. Sugimoto D, Myer G, Barber Foss K, Hewett T. Specific exercise effects of preventive neuromuscular training intervention on anterior cruciate ligament injury risk reduction in young females: meta-analysis and subgroup analysis. Br J Sports Med 49: 282–289, 2015.
51. Sugimoto D, Myer G, Bush H, Klugman M, Medina McKeon J, Hewett T. Compliance with neuromuscular training and anterior cruciate ligament injury risk reduction in female athletes: A meta-analysis. J Athl Train 47: 714–723, 2012.
52. Sugimoto D, Myer G, Foss K, Hewett T. Specific exercise effects of preventive neuromuscular training intervention on anterior cruciate ligament injury risk reduction in young females: meta-analysis and subgroup analysis. Br J Sports Med 49: 282–289, 2015.
53. Visek A, Achrati S, Manning H, McDonnell K, Harris B, Dipietro L. The Fun Integration Theory: Towards sustaining children
and adolescents sport participation. J Phys Act Health 12: 424–433, 2015.
54. Whitehead M. The concept of physical literacy. Eur J Phys Ed 6: 127–138, 2001.
55. World Health Organization. Global Recommendations on Physical Activity for Health. Geneva, Switzerland: WHO Press, 2010.
56. Zouita S, Zouita A, Kebsi W, Dupont G, Ben A, Ben S, Zouhal H. Strength training reduces injury rate in elite young soccer players during one season. J Strength Cond Res 30: 1295–1307, 2016.