Sport Specialization in Youth: A Literature Review

Journal of the American Chiropractic Association, Apr 2004 by Hecimovich, Mark

Physiological/Physical Factors

Adverse consequences from intense training and competition have been reported in the lay and medical literature.42 Anecdotal reports and case studies, however, are insufficient grounds for drawing conclusions about the safety of intense training or high-level competition.10 Research has demonstrated that a high emphasis on competition greatly increases the desire for coaches to over-train children with inappropriate volume and intensity in practices/competition. Adverse physiological consequences follow excessive training, including delayed menarche and increased risk of overuse injuries to immature musculoskeletal systems.43

While some researchers note that critical periods may exist when a sport is learned best,44 scientific evidence does not support the belief that specific skills must be learned and perfected before the onset of puberty.

Moreover, future athletic excellence is difficult to predict because of the ongoing effects of growth and maturation and the variability of learning experiences at different times and in different settings.45,46 Early exposure to a variety of activities is more beneficial than prematurely pushing a child to learn a particular skill or specialize in one sport before he or she is developmentally ready.46,49 In the physiological/physical realm of sport specialization, there are four areas of concern: musculoskeletal, nutritional, sexual maturation, and cardiac.

Musculoskeletal System. An increase in physical activity stimulates musculoskeletal growth, and repetitive stress can stimulate positive adaptive responses in the musculoskeletal structures. Excessive stress or overload, however, can lead to tissue breakdown and injury. To realize maximum gains, athletes must correctly identify and train just below the threshold for injury.10

Excessive sports training in child and adult athletes can lead to overuse injuries (tendinopathy or tendinosis, apophysitis, stress fractures). Growing athletes may be predisposed to repetitive stress injuries, such as traction apophysitis (Osgood-Schlatter disease, Sever disease, medial epicondylitis [Little League elbow]), injuries to developing joint surfaces (osteochondritis dissecans), and/or injuries to the immature spine (spondylolysis, spondylolisthesis, vertebral apophysitis).50 The physiological stress experienced by many prepubescent athletes is caused by repetitive training cycles: swimmer's shoulder, tennis player's elbow, and runner's stress fractures are common examples. It is important for athletes to specialize in a sport when they are physically ready to participate in repetitive cycles.51

Nutrition. For the child athlete, an adequate diet is critical because nutritional needs are increased with the training and growth process.10 It has been noted that female gymnasts are at risk for nutritional disorders due to the pressure to maintain a prototypic mesomorphic body appearance (i.e., thin and muscular). This pressure encourages atypical eating behavior, which may lead to eating disorders52-55 often seen in gymnastics.38