Exercise training and body composition in childhood.

The influence of exercise training on body composition changes in children is examined in terms of muscle, bone, and fat development. Because of the inexact body composition methodologies in general use and an over-reliance on the two-components system--fat and fat-free body--the extent of changes especially for muscle and bone with exercise training has not been well quantified. With the recent development of new methodologies these limitations may be overcome. The relationship of body composition to health related fitness is also explored with an emphasis on establishing fitness standards for body fatness and the need for research on the etiology of lower back pain and osteoporosis.