A three-year study of the effects of exercise on active young men.

The changes occurring in leanness-fatness, physical working capacity, isometric strength, and motor ability have been followed in 20 highly active young adult males over a period of 3 years. Body weight and estimated percentage of fat increased over the 3-year period but there were no significant changes in the other variables. Within the 3-year period physical working capacity and relative leanness-fatness showed significant variations which are attributed to the state of training of the subjects. Strength was found to be highly related to somatotype but was apparently not influenced by the state of training; changes in relative leanness-fatness occurring with training were found to be influenced by somatotype.