Likewise, the studies showed body composition improvements in 10-to 14-year-old boys and girls following eight weeks of sensible strength training. On the average, the young strength exercisers added 3 to 4 pounds of lean weight and lost 1 to 2.5 pounds of fat weight during the training period.

One of the most important outcomes of these five studies involving well over 100 boys and girls was the absence of any exercise-related injuries. It is therefore suggested that well-designed and well-supervised strength training programs are a safe and productive means for improving muscle strength and body composition in teen and pre-teen boys and girls.

Although the long-term benefits of youth strength training have not yet been documented, it is logical to assume that leaner and stronger youth may become leaner and stronger adults. Developing a strong musculoskeletal system during the formative years may also reduce the risk of injuries and degenerative diseases during the adult years.

The medically-based guidelines for youth strength training programs emphasize an uncrowded facility, appropriate equipment, physician clearance, qualified instructors, brief exercise periods, gradual progression, no competition and no maximum lifts. When appropriate training guidelines are observed, strength exercise is a recommended physical activity for teen and pre-teen boys and girls.

Wayne L. Westcott, Ph.D., is fitness research director at the South Shore YMCA in Quincy, MA., and author of several fitness books including the new releases, Building Strength and Stamina and Strength Training Past 50.