Secondary Logo

Journal Logo

Special Populations: Section Articles

Early Sport Specialization

Roots, Effectiveness, Risks

Malina, Robert M.

Author Information
Current Sports Medicine Reports: November 2010 - Volume 9 - Issue 6 - p 364-371
doi: 10.1249/JSR.0b013e3181fe3166
  • Free



Sport is a major context of physical activity for youth, but emphasis on those aspiring for elite status detracts from the potential values of sport participation for all children and adolescents (40). The talented few are a very visible minority, whereas the overwhelming majority of youth who participate pass under the radar. Unfortunately, most attention and resources, and commentaries in print and electronic media, focus on the exceptional minority. One consequence is specialized, systematic training in a single sport at a relatively young age with the goal of attaining elite status. Statistics documenting the trend to specialization are difficult to specify, but the following is an increasingly common observation: "A growing number of coaches, parents, and children believe that the best way to produce superior young athletes is to have them play only one sport from an early age, and to play it virtually year-round" (21). This article considers the roots, consequences, and limited data on the effectiveness of early specialization in sport.


Several factors have contributed to early sport specialization. These factors interact with each other and the demands of sport systems.

Perceptions of the East

The relative success of sport systems in former communist countries of Eastern Europe has contributed to a perceived need for early specialization. It commonly has been perceived in the West that systematic training in Eastern Europe began at early ages and involved year-round participation. The relatively young ages of competitors in several sports were highlighted by the media and reinforced early specialization as a requisite for success. Eastern European talent identification and development programs varied to some extent by sport and emphasized exposure to a variety of activities and skills in early sport experiences (multilateral training). Specialization in most sports tended to occur after puberty; "early entry sports," specifically gymnastics, diving, figure skating, and to some extent swimming were exceptions (8,9,15,29,52). The perception of early specialization was reinforced by coaches and sport scientists who migrated to Western countries and often became involved in elite programs. Eastern European programs have been modified over time and probably with cultural setting. A recent modification is long-term athlete development, which emerged in the 1990s (4). The scientific basis and effectiveness of the various programs has not been evaluated systematically, and in some instances, recent applications seemingly have taken the form of a business.

Getting Ahead

Parents are major players in specialization in sport and other endeavors. In the classic study Developing Talent in Young People (7), talented individuals in sport (tennis, swimming), art (pianists, sculptors), and science (research neurologists, mathematicians) - fields in which success (elite status) was attained at relatively young ages - were studied. Home environments of the talented shared three characteristics: child-centered - parents channeled their own interests into and were very involved in the activities of the children; concentration on development in the specific endeavor; and emphasis and value on achievement (53).

Parents want what is best for their children and will do what they can to facilitate prospects in school, sport, and other activities. This is consistent with time trends among children in the United States aged 3-12 yr. From 1981 to 1997, discretionary time, television time, and time in unstructured activities (play) decreased, while time in school or day care, time reading and studying at home, and time in organized activities including hobbies, sports, and arts increased (58). Time in organized activities at early ages probably has increased since. Approximately one third of children 3-4 yr of age in the United States were enrolled in preschool in 1993 (3), whereas approximately 47% and 74% of 3- and 4-yr-old children, respectively, were enrolled in public and private preschool programs in 2007 (5). Among youth in the United Stated 18 yr and younger participating in organized sports, children 6 yr and younger comprised 9% in 1997, 14% in 2000, and 12% in 2008 (48).

Driven for success of their children, parents often perceive an early start as necessary to obtain an edge. The Tiger Woods story - early introduction to golf, deliberate practice at a very early age, a dominating parent, a highly regulated life through childhood and adolescence into adulthood, and eventual success is well documented (20). This story and probably others have functioned to influence parental perceptions of the need for an early start in sport.

Future education also is a concern of parents, and sport is a potential venue for scholarships (see later in this article). Seemingly in contrast to early specialization, holding youngsters in grade for a developmental advantage compared to peers, "redshirting," has been noted in preschool, especially in affluent communities (25,61). Although older children within grade learn more, some evidence suggests greater frequency of behavior problems over the long term (57).

"Redshirting" also is well documented in football where size is perceived as important. Parents hold a boy back in grade for one year, often at the recommendation of a coach, for the purpose of gaining a size and strength advantage over grade peers. This often occurs in 6th through 8th grades when differences in size and strength among boys are considerable (41).

Some parents are influenced by potential economic benefits. Management groups sign talented youth at very young ages and parents form corporations to fund instruction and training under the tutelage of expert coaches. The young athlete is the commodity and investors share in future earnings. It is not uncommon for larger clubs to find jobs for parents to lure talented athletes.

Parents and home environment clearly are important in specialization. The influence of coaches and other adults associated with a sport, probably interacting with parents, in specialization and the lives of young athletes needs systematic evaluation.


Children often are labeled as gifted or talented at an early age in sport, arts, and academics. Such labeling probably encourages specialization. Two issues are of relevance: What is the impact of labeling on individual and parental expectations, and does the child have a voice in the decision to specialize?

Pursuit of Scholarships

Many youngsters with encouragement of parents begin specialized sport training in a single sport at young ages with the goal (hope) of obtaining a college scholarship, often with considerable expense for the family (60). There is, however, a degree of unreality in perceptions of scholarships for sport. Only 22/1000 girls (2.2%) and 20/1000 boys (2.0%) participating in high school sport in 1999 to 2000 received partial or full scholarships; estimates for full scholarships were lower, 1/81 girls (1.2%) and 1/93 boys (1.1%). The scholarship yield is very small, and financial aid rarely covers tuition, room, and board at most colleges and universities (50).

Although potential financial returns on time and money invested in athletic development and probability of scholarships are overestimated, the road for talented youth is linked to special programs. Select or travel teams recruit youth for the purpose of competing at a higher level; they emerge at approximately the 10- to 12-yr age range in basketball, baseball, softball, and soccer. The programs are independent of interscholastic programs and encourage participation in a single sport year-round. Select programs vary in cost, most of which is borne by parents. Funds for youth with limited family resources usually are available, although sources are not always clear.

Discussions of talented male youth basketball and football players dominate the media. The extent of the search for talent in basketball at young ages is evident in The Hoop Scoop, a commercial enterprise that nationally ranks players in 6th to 12th grades (20). Given the importance of visibility, lobbying by coaches and parents to have a child/player ranked is considerable. Select basketball teams for the elite usually are active after the scholastic season and are prime recruiting grounds for collegiate programs. In many ways, select team coaches have become brokers in the recruiting process. Shoe companies often are involved - seeking the best players and their parents for potential endorsements (14).

U.S. football has its own methods. National media and several independent services regularly rank high school football players locally and nationally. Rankings presumably bring talented players to the attention of college coaches and others involved in recruiting. Downward extension of player rankings is apparent in the Football University Youth All-American Bowl, a series of three games for talented 7th and 8th graders (18).

Pursuit of Professional Contracts

Some youth and/or parents are driven by the opportunity for a professional contract. A very small but visible percentage of high school athletes move directly to professional contracts, although rules vary by sport. Club-based sports often have developmental programs, academies, including soccer in most countries, baseball in the Caribbean, and increasingly basketball in Europe and Africa. Corporate money also permeates developmental programs for young tennis players (40). Youth athletes are developed for the international market (including college scholarships) and jobs may be offered to families to bypass official regulations. Given potential economic benefits, it is no wonder that parents facilitate and encourage early specialization.

Sporting Goods Industry

The sporting goods retailing industry is a key player in specialization. According to the Mercanti Group, "A regimen of organized games, training and practice is now the norm among youngsters, while casual participants have dropped out of team sports. … This reflects a trend among individuals to sport specialization, in which youngsters play a single sport year-round. … Sport specialization has upped demand for sport training and conditioning programs, facilities, and products" (46).

A major part of any business venture is advertising aimed at parents and youngsters.

Expertise Research

Understanding expert performance is a popular topic in sport psychology. The theoretical framework of expert performance in any endeavor is, however, more complicated. Expert performances are "… Acquired characteristics resulting from extended deliberate practice" (17). Primary emphasis is on quality of instruction and practice, and ability of the individual to organize the specific knowledge. It involves explicit teaching of specific skills, supervised practice, and corrections as needed; this is formal learning. Frequent repetition under the watchful eye of an expert coach is a feature of deliberate practice. The accumulation of experience ultimately is represented in the motor and cognitive neural substrates. Biological variables and biobehavioral interactions were not considered explicitly in early discussions, although the potential role of biological factors, specifically genetic, is recognized (16).

Observations and anecdotes have suggested, in general, that at least 10 yr of experience and 10,000 h of deliberate practice are necessary for international success in music, chess, and other disciplines. This view has been extended to sport (56), although not all evidence is consistent with the proposed time scales (1,23). Nevertheless, the 10-yr or 10,000-h rule has made its way into the popular press (4,12,24,33) and probably has contributed to early specialization. Parents thus may see an early start in a single sport as essential, often to the exclusion of other childhood activities and sports.

Many discussions of expertise overlook the reality of life for many children involved in sport. Many sports and sport-related activities are carried out in informal settings, that is, "street games." These involve major time commitments and frequent repetitions, but not under the eye of a coach. Street games represent what is now labeled deliberate play (13). They involve trial and error, experimentation, and repetition; exposure to different conditions, skills, and rules; and variable settings associated with numbers available and seasonal changes. Skills acquired under such circumstances represent informal or implicit learning (11). Sport and sport-related skills apparently are learned without awareness or explicit knowledge of the skills. It is postulated that skills learned under informal conditions are influenced less by fatigue and stress (51). Research on implicit learning in sport is in its infancy but is expanding (44,45).


Sport is exclusive! Few athletes make it to elite levels. This is illustrated in the estimated numbers of participants in four organized team sports in the United States in 2000 summarized in Table 1. The base is broad among youth and is reduced markedly as sport becomes more selective. It thus is no surprise that talent identification and development programs and, by inference, early specialization have limited success.

Estimated numbers of participants in five organized teams sports in the United States from youth to elite levels in 2000.a

Although the apparent success of the early "scientific selection" protocols of Eastern Europe often was lauded (9), the process apparently facilitated hormonal manipulation of young athletes (22,31), and achievements were tainted. Other observations suggest a relatively small yield. Only 0.14% of 35,000 highly qualified Russian athletes training at sport schools, including 2700 candidates for select schools, succeeded from entry-level selection to high-level sports mastery (34).

A 7-yr follow-up of German athletes in seven Olympic sports indicated that only 15 of 4972 (0.3%) selected at the youngest level in each sport eventually ranked among 10 best international senior athletes, while a 3-yr follow-up noted that 192 of 11,287 athletes in elite sport schools (1.7%) attained a medal in an international championship (28).

Corresponding data for the United States are not available, but the likelihood of competing in sport beyond high school provides similar results (Table 2). The probability of moving from high school to major professional sport is small. The highest likelihood of moving from high school to collegiate sport is in ice hockey, which has the smallest number of participants. Probability of moving from college to professional is highest for baseball, which reflects its extensive minor league system. Relatively few make it from the minor to major leagues. Corresponding probabilities for other sports are considerably lower.

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

Sport background and career trajectories of talented athletes provide additional insights into the relative merits of early specialization. For example, "quick" (≤4 yr) and "slow" (≥10 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 ± 4.5 vs 7.9 ± 2.5 yr) and participated in more sports before starting the main sport (3.3 ± 1.6 vs 0.9 ± 1.3 yr). Athletes on the "quick" path rarely participated in another sport after beginning their main sport, while those on the "slow" path participated in an average of two sports after beginning their main sport (49).

Three observations for German national athletes in all Olympic sports (N = 1558) have implications for specialization. Successful athletes participated in more than one sport either before or parallel to their current sport (juniors 2.2 ± 1.4; top-level athletes 2.4 ± 1.6). Approximately 64% of international finalists and 53% of less-successful top athletes participated in other sports. And internationally successful athletes continued training in other sports to a later age (27). By inference, specialized training in the primary sport began later.

Among U.S. university female athletes, the majority in diving, tennis, golf, track and field, basketball, and volleyball had their first organized sport experiences in a sport other than their current sport; swimmers were an exception (Table 3). Sixty-three of 376 athletes (17%) participated only in their current sport: 25 swimmers, 25 track and field athletes; 9 in diving, tennis, and golf, and 4 in basketball and volleyball. The contrast between individual and team sports was clear. Consistent with collegiate divers, only 25 of 189 U.S. Junior Olympic divers had their first organized sport experience in diving (42).

Sports participation background and age at specialization in university female athletes in seven sports.a


Early specialization is not without risk. Several subsequently are noted.

Social Isolation

Focus on a single sport and the associated time commitment may foster isolation from age and sex peers, especially during adolescence, and may alter relationships with peers, parents, and family. It also limits experiences in other sports and activities. An increasing number of talented young athletes in the United States are homeschooled and may miss opportunities for important nonsport developmental experiences - peer interactions, social activities, and independence.


The lives of young elite athletes tend to be highly regulated. This may foster overdependence on others and in many cases loss of control of what is happening in life. Elite young athletes may be trapped by fame, which in turn may influence perceptions of their qualities as a human being - an athlete and not a person, a commodity to be marketed. Arrested behavioral development is a potential consequence, as are socially maladaptive behaviors during youth and extending into adulthood. These may be overlooked until something dramatic happens. The following comment in a brief article, "Michael Jackson, Death by Show Business," merits attention: "There is a theory that applies to any child star, that the age at which you become famous is the age at which some part of you becomes forever, and irreparably, arrested" (10). This indeed would be an interesting topic for study among elite athletes.


Burnout, sometimes described as burning desire (35), often is attributed to early specialization. Burnout is not sudden but develops over time. It is associated with perceptions by the athlete that he or she cannot meet the physical or psychological demands placed upon him or her. Reduction in sport accomplishments and associated rewards are additional factors. Signs of chronic stress include agitation, sleep disturbances, loss of interest in practice, depression, lack of energy, skin rashes, nausea, and frequent illness (26,62). Many factors are involved in burnout, but three are primary: negative performance evaluations - critical rather than supportive, inconsistent feedback from coaches and officials - mixed messages, and overtraining. Contributing factors include injury (often a trigger); overprotection by coaches, trainers, parents, and sport officials; and perceptions of not being able to meet self-imposed expectations or those of others (26). Injury limits activity, while overprotection limits exposure to new situations and opportunities through which the young athlete can learn coping mechanisms and social relationships. These can foster feelings of lack of control, dependency, and a sense of powerlessness. Sport environments conducive to burnout in youth are, of course, superimposed on and interact with normal demands of "growing up" - physical growth, biological maturation, and behavioral development (41).


Commitment to a single sport at a relatively early age immerses a youngster in a complex world regulated by adults. The youngster and perhaps parents often place blind faith in the system. This is a setting that facilitates manipulation.

Social manipulation perhaps is most evident in preferential treatment by sport systems, schools, management groups, and media. It also is evident in differential access to resources for the elite - travel, tutors, and access to scholarships, among others. Preferential treatment may lead to overdependence on and/or control by coaches and sport organizations, and altered social relationships with peers, parents, and family. Abuse - emotional, physical, and sexual - is a potential byproduct of dependence. Stresses associated with year-round training and competitions also are byproducts of an environment of overdependency and accumulate over time. Among young women, 3 of 27 highly trained gymnasts and 4 of 16 moderately trained swimmers were considered at risk for "a manifest mental disorder over time" (59).

Age modification is a form of manipulation. Age group competition is a feature of virtually all youth sports. The integrity of competitions is based upon the assumption that ages are accurate and records of chronological age (birth certificate, passport) are valid. Problems with accurate age reporting appear on a regular basis in youth sports and with elite athletes (36). Who is the source of inaccurate reporting or age falsification? Look to those who regulate youth in sport - coaches, administrators, trainers, parents, agents and perhaps others.

Dietary manipulation, direct and indirect, is a concern in some sports. Some adolescents may institute self-imposed dietary restrictions, especially in aesthetic sports such as artistic gymnastics, figure skating, and ballet. Pressures, at times subtle, to maintain or lose weight by young athletes, when the natural course of growth is to gain weight, can lead to disordered eating and clinical eating disorders. Comments on body weight from trainers, coaches, and judges can trigger disordered eating. Dietary restrictions on elite young athletes also may come directly from the sport system. Gymnasts in the former German Democratic Republic were on a dietary regime "…intended to maintain the optimal body weight, i.e., a slightly negative energy balance, and thus a limited energy depot over a long period" (30). Such intentional energy deficit is abuse. On the other hand, the culture of U.S. football with emphasis on size and mass may pressure some boys to gain weight and increase the risk of overweight/obesity (43).

Chemical manipulation seemingly is rampant in sport - dietary and other supplements, diuretics, stimulants, and of course performance-enhancing drugs. Small percentages of youth, athletes and nonathletes, apparently have tried or have been enticed to try performance-enhancing substances (19,32). Surprisingly, parents, friends, and even family physicians were indicated by the adolescents as the source of performance enhancers (32).

Merchandising is commonplace in sport at all levels. What is overlooked is the fact that young athletes are often the merchandise. Development of young athletes in many sports is a long-term investment. A talented 5-yr-old soccer prodigy in the Ajax system was described as "…well worth this investment of time and attention, because one day he might be sold to Chelsea or Real Madrid or Juventus for millions" (54).

Talented young athletes are regularly sought-after commodities, and they often are exploited. Corporate money permeates youth tennis. Soccer, baseball, basketball, and football players are widely scouted and actively pursued at young ages. High school sport programs are publicly subsidized feeder systems for collegiate and professional basketball and football, and to a lesser extent baseball. Many athletes are from lower socioeconomic backgrounds, so the potential for exploitation of the youngster and family is heightened. Sport often is placed ahead of education and also is the lure for education (scholarships). Youth basketball coaches for select teams have become brokers controlling access of players to college coaches. Many clubs develop young players for the international market (soccer in Africa and South America, baseball in the Caribbean), and jobs may be offered to families to bypass official regulations. The problem is of sufficient magnitude that international legislation to regulate clubs and agents, especially those pursuing underage players, is under discussion (6).


Overuse injuries are a consequence of repeated microtrauma in a tendon, muscle, or bone associated with chronic repetition of specific sport activities - tennis serving, baseball pitching, gymnastic routines, running, and shoulder action in swimming, for example (2). Although specialization may place a youngster at risk for overuse injuries, other factors intrinsic to the young athlete and sport environment, and their interactions (39), probably are more important.

Compromised Growth and Maturation

Complications in growth and maturation occasionally are attributed to early intensive sport training, but data are not convincing. The short stature and later maturation of elite artistic gymnasts and later maturation of ballet dancers are examples most often attributed to intensive training at young ages (37,38). It is difficult, however, to establish early specialization and training as causative factors underlying the growth and maturity status of young gymnasts and dancers, and perhaps female athletes in other sports. Allowing for variation in sampling and methodology, constitutional factors in the selection and retention processes of gymnastics, ballet, and other early entry sports need careful consideration. If early specialization and training can compromise growth and maturation, it is essential to partition their effects from the extremely selective physical and aesthetic criteria of gymnastics and ballet, requisite skills, differential dropout, and the complexities of the tightly controlled elite sport/dance environments before causality can be established (37,38,41).


Few individuals who specialize in sport at young ages make it to elite levels and reap the social, economic, and other benefits associated with success. The overwhelming majority drop out along the way. Nevertheless, specialization in sport at relatively young ages is a fact of life for many children. Factors underlying specialization interact with each other and demands of sport systems, which essentially are businesses operated by adults. Adults also are implicated, directly and indirectly, in consequences of specialization.

Information on the effectiveness of early specialization and the long-term success of young athletes is limited. Only the successful are highlighted, but early success is no guarantee of later success in elite sport. Limiting experiences to a single sport year-round may not be the best path to elite status.

It is essential to keep sport in perspective. Young sport participants, including talented athletes, are children and adolescents with the needs of children and adolescents. Their goal is to "grow up" - biologically grow and mature and behaviorally develop. These processes place many demands on youth, and the demands of sport are superimposed upon them. Unfortunately, talented young athletes are often pawns in a complex matrix - the sport, adults who run the sport, parents, schools, sporting goods and services industries, media, and in some cases international politics. Sport scientists can be in a tenuous position studying the development of young athletes while avoiding manipulation by or entrapment in the matrix.


1. Abernethy B, Farrow D, Berry J. Constraints and issues in the development of a general theory of expert motor performance. A critique of the deliberate practice framework. In: Starkes J, Ericsson KA, editors. Expert Performance in Sport: Recent Advances in Research on Sport Expertise. Champaign (IL): Human Kinetics; 2003. p. 349-69.
2. American Academy of Pediatrics, Council on Sports Medicine and Fitness. Overuse injuries, overtraining, and burnout in child and adolescent athletes. Pediatrics. 2007; 119:1242-5.
3. Assistant Secretary for Planning and Evaluation. Education and Achievement, Enrollment/Attendance [Internet]. 1993 [cited 2010 September 16]. Available from:
4. Balyi I. Sport system building and long term athlete development in Canada: the situation and solutions. Coaches Report. 2001; 8(1):25-8.
5. Barnett WS, Epstein DJ, Friedman AH, et al. The State of Preschool 2009, State Preschool Yearbook, Executive Summary. Washington, DC: The National Institute for Early Education Research; 2009.
6. BBC News. EU signals bigger role in sport [Internet]. 2007 BBC News [cited 2007 July 11]. Available from:
7. Bloom BS, editor. Developing Talent in Young People. New York: Ballantine Books; 1985.
8. Bompa T. From Childhood to Champion Athlete. Toronto: Veritas Publishing; 1995.
9. Bompa T. Talent identification. In: Sports Science Periodical on Research and Technology in Sport, Physical Testing G1. Ottawa. Coaching Association of Canada; 1985.
10. Brown M. Michael Jackson, death by showbusiness [Internet]. 2009 Daily Telegraph [cited 2009 June 28]. Available from:
11. Cleeremans A, Destrebecqz A, Boyer M. Implicit learning: news from the front. Trends Cog. Sci. 1998; 2:406-16.
12. Colvin G. What it takes to be great [Internet]. 2006 Fortune Magazine [cited 2010 September 16]. Available from:
13. Côté J. The influence of the family in the development of talent in sport. Sport Psychol. 1999; 13:395-417.
14. Danley S. On basketball: trying to corner the market on the best players [Internet]. 2007 New York Times [cited 2007 July 11]. Available from:
15. Drabik J. Children and Sports Training. Island Pond (VT): Stadion Publishing Company; 1996.
16. Ericsson KA. The development of elite performance and deliberate practice: an update from the perspective of the expert-performance approach. In: Starkes J, Ericsson KA, editors. Expert Performance in Sport: Recent Advances in Research on Sport Expertise. Champaign (IL): Human Kinetics; 2003. p. 49-81.
17. Ericsson KA, Krampe RTh, Tesch-Römer C. The role of deliberate practice in the acquisition of expert performance. Psychol Rev. 1993; 100:363-406.
18. Evans T, Thamel P. Barely teenagers, already groomed for stardom [Internet]. 2009 New York Times [cited 2009 January 3]. Available from:,%20already%20groomed%20for%20stardom&st=cse.
19. Faigenbaum AD, Zaichkowsky LD, Gardner DE, Micheli LJ. Anabolic steroid use by male and female middle school students. Pediatrics. 1998; 101(5):e1-6.
20. Farrey T. Game On: The All-American Race to Make Champions of Our Children. New York: ESPN Books, 2008.
21. Finley B. A single goal in common [Internet]. 2006 New York Times [cited 2006 December 16]. Available from:
22. Franke WW, Berendonk B. Hormonal doping and androgenization of athletes: a secret program of the German Democratic Republic government. Clin. Chem. 1997; 43:1262-79.
23. Fraser-Thomas J, Côté J. Youth sports: implementing findings and moving forward with research. Athl. Insight Online J. Sport Psychol. 2006; 8(3):12-27.
24. Gladwell M. Outliers: The Story of Success. New York: Little, Brown; 2008.
25. Gootman E. Preschoolers grow older as parents seek an edge [Internet]. 2006 New York Times [cited 2006 October 20]. Available from:
26. Gould D, Dieffenbach K. Psychological issues in youth sports: competitive anxiety, overtraining, and burnout. In: Malina RM, Clark MA, editors. Youth Sports: Perspectives for a New Century. Monterey (CA): Coaches Choice; 2003. p. 149-70.
27. Güllich A, Emrich E. Evaluation of the support of young athletes in the elite sport system. Eur. J. Sport Soc. 2006; 3:85-108.
28. Güllich A, Emrich E, Schwank B. Evaluation of the support of young athletes in the elite sport system [Internet]. German Olympic Sports Confederation [cited 2009 February 25]. Available from:
29. Hartley G. A comparative view of talent selection for sport in two socialist states - the USSR and the GDR - with particular reference to gymnastics. In: The Growing Child in Competitive Sport. Leeds (UK): The National Coaching Foundation; 1988. p. 50-6.
30. Jahreis G, Kauf E, Frohner G, Schmidt HE. Influence of intensive exercise on insulin-like growth factor I, thyroid and steroid hormones in female gymnasts. Growth Reg. 1991; 1:95-9.
31. Kalinski MI, Kerner MS. Empfehlungen zum Einsatz von anabolen Steroiden im Sport aud ser ehemaligen Sowjetunion - Daten aus einem geheimen Dokument (Recommendations for androgenic-anabolic steroid use by athletes in the former Soviet Union: Revelations from a secret document). Deutsche Z. Sportmed. 2002; 53:317-24.
32. Laure P, Binsinger C. Adolescent athletes and the demand and supply of drugs to improve their performance. J. Sports Sci. Med. 2005; 4:272-7.
33. Lehrer J. How to raise a superstar [Internet]. 2010 Wired Science [cited 2010 September 16]. Available from:
34. Ljach WI. Kinderhochleistungssport in Rußland (High performance sport in childhood in Russia). Leistungssport. 1997; 27(5):37-40.
35. Lonsdale CA. Burning out or burning desire? Investigating athlete burnout and engagement in elite New Zealand athletes [Dissertation]. Dunedin: University of Otago; 2006.
36. Malina RM. Estimating passport age from bone age: fallacy. Insight, The FA Coaches Association Journal. 2005; >Autumn/Winter>:23-7.
37. Malina RM. Growth and maturation of elite female gymnasts: is training a factor? In: Johnston FE, Zemel B, Eveleth PB, editors. Human Growth in Context. London: Smith-Gordon; 1999. p. 291-301.
38. Malina RM. Growth and maturation of young athletes: is training for sport a factor? In: Chang KM, Micheli L, editors. Sport and Children. Hong Kong: Williams & Wilkins; 1998. p. 133-61.
39. Malina RM. Injuries in organized sports for children and adolescents. In: Frost JL, editor. Children and Injuries. Tucson, AZ: Lawyers and Judges Publishing Co; 2001. p. 199-248.
40. Malina RM. Organized youth sports - background, trends, benefits and risks. In: Coelho e Silva MJ, Figueiredo AJ, Elferink-Gemser MT, Malina RM, editors. Youth Sports, Volume I: Participation, Trainability and Readiness. Coimbra (Portugal): Coimbra University Press; 2009. p. 2-27.
41. Malina RM, Bouchard C, Bar-Or O. Growth, Maturation, and Physical Activity, 2nd edition. Champaign (IL): Human Kinetics; 2004.
42. Malina RM, Geithner CA. Background in sport, growth status, and growth rate of Junior Olympic Divers. In: Malina RM, Gabriel JL, editors. U.S. Diving Sport Science Seminar 1993, Proceedings. Indianapolis (IN): United States Diving; 1993. p. 26-35.
43. Malina RM, Morano PJ, Barron M, et al. Overweight and obesity among youth participants in American football. J. Pediatr. 2007; 151:378-82.
44. Maxwell JP, Masters RS, Eves FF. From novice to no know-how: A longitudinal study of implicit motor learning. J. Sports Sci. 2000; 18:111-20.
45. Maxwell JP, Masters RSW, Kerr E, Weedon E. The implicit benefit of learning without errors. Q. J. Exp. Psychol. 2001; 54A:1049-68.
46. Mercanti Group. Major sporting goods retailers to benefit from private label expansion, sports specialization and other industry trends [Internet]. 2008 [cited 2008 November 5]. Available from:
47. National Collegiate Athletic Association. A Career in Professional Sports: A Guide for Making the Transition. Indianapolis (IN): National Collegiate Athletic Association; 2004.
    48. National Council of Youth Sports. Report on Trends and Participation in Organized Youth Sports. Stuart (FL): National Council of Youth Sports; 2008.
    49. Oldenziel KE, Gagne F, Gulbin J. Factors affecting the rate of athlete development from novice to senior elite: how applicable is the 10-year rule? Paper presented at the 2004 Pre-Olympic Congress - Sport Science through the Ages. Thessaloniki, Greece, August 6-11, 2004.
    50. Pennington B. The scholarship divide: expectations lose to reality of sports scholarships [Internet]. 2008 New York Times [cited 2008 March 10]. Available from:
    51. Poolton JM, Masters RSW, Maxwell JP. Passing thoughts on the evolutionary stability of implicit motor behavior: performance retention under physiological fatigue. Consciousness Cognition. 2007; 16:456-68.
    52. Rost K, Schon R. Talent Search for Track and Field Events: Exercise Leader and Coach's Manual for Talent Selection and Basic Training of Track and Field Events (Age Class 9 to 14). Leipzig, Germany: German Track and Field Association (translated by MR Hill, H Nowoisky, NN Wegink, University of Utah); 1997.
    53. Sloane KD. Home influences on talent development. In: Bloom BS, editor. Developing Talent in Young People. New York: Ballantine Books; 1985. p. 439-76.
    54. Sokolove M. How a soccer star is made [Internet]. 2010 New York Times Magazine [cited 2010 June 6]. Available from:
    55. Sporting Goods Manufacturers Association. U.S. Trends in Team Sports. North Palm Beach, (FL): Sporting Goods Manufacturers Association, 2001.
      56. Starkes J, Ericsson KA, editors. Expert Performance in Sport: Recent Advances in Research on Sport Expertise. Champaign (IL): Human Kinetics; 2003.
      57. Stipek D. At what age should children enter kindergarten? A question for policy makers and parents. Social Policy Report (Society for Research in Child Development) 2002; 16(2):3-16.
      58. Sturm R. Childhood obesity - what can we learn from existing data on societal trends, part 1. Prev. Chron. Dis. 2005; 2(1):1-9.
      59. Theintz G, Ladame F, Kehre E, et al. Prospective study of psychological development of adolescent female athletes: initial assessment. J. Adol. Health. 1994; 15:258-62.
      60. Tritto C. Paying for performance: velocity, hammer bodies cash in as parents invest thousands in child athletes [Internet]. 2006 St. Louis Business Journal [cited 2008 November 5]. Available from:
      61. Weil E. When should a kid start kindergarten? [Internet] 2007 New York Times [cited 2007 June 4]. Available from:
      62. Weinberg RS, Gould D. Foundations of Sport and Exercise Psychology. Champaign (IL): Human Kinetics; 1995.
      © 2010 American College of Sports Medicine