Since the early 1960s, there has been concern in the physical education community that participation in a strength-training program could have an adverse effect on a young person’s growth and stature. The fear was that lifting weights could damage a child’s growth plates, which are cartilaginous structures covering the ends of the long bones where growth occurs. This concern seems to have come from a 1964 report indicating that children in remote areas of Japan who performed heavy labor where short in stature. The report, however, failed to control for etiologic factors such as poor nutrition and hours-long heavy labor. Current data show no evidence of a decrease in stature in children who perform a well-designed strength-training program. Additionally, growth-plate fractures have never been reported in any prospective youth strength training study published to date. Indeed, research conducted over the past 20 years offers credible evidence that strength training can be a safe and effective method of conditioning for children, as long as appropriate guidelines are followed.
Developing a strong and fit musculoskeletal system is the cornerstone of a healthy exercise-conditioning program. Children as young as six have shown gains in muscular strength of approximately 30 to 50% following short-term strength-training programs. Additionally, childhood and adolescence may be the period during which the bone-building process responds most favorably to the mechanical loading of physical activities such as strength training. It seems that maximizing bone mineral density (BMD) during youth with exercise and proper nutrition may help to prevent the condition of osteoporosis seen in older adults.
A regular strength-training program has been shown to help youth involved in athletic activities reduce their risk of muscle imbalance and overuse injuries. Children should have good overall strength before engaging in competitive sports that can place excessive stress on an unconditioned musculoskeletal system. Focusing only on sport-specific skills typically provides too little stimulus for many major muscle groups and too much stimulus on others, with the result being injury to the child. For this reason, it is crucial that children develop fundamental fitness before specializing in the specific-skill training required for sport.
Leading organizations, including the American College of Sports Medicine (ACSM) and the National Strength and Conditioning Association (NSCA) all support strength training for children and adolescents as long as the appropriate guidelines are followed. Although there is no minimum age requirement for engaging in a strength training program, all children considering participation should have the emotional maturity to accept and follow directions and should understand the benefits and risks associated with resistance training. Children as young as six have participated in and benefited from a strength-training program. However, there have been reports that children younger than age six are more likely than older children to be injured with weight-training equipment.
Youth strength training is relatively safe when compared with other sports and activities in which children and adolescents regularly participate. One retrospective evaluation of strength training injures incurred by 13 to 16 year olds revealed that strength training was remarkably safer than other sports such as soccer, basketball, and football. Currently, there are no justifiable safety reasons to prohibit children and adolescents from participating in well-designed strength programs.