Lean and fat component of the human thigh. The effects of immobilization in plaster and subsequent physical training.

Changes in thigh components were investigated with the one-legged inactivity- and training-model using 22 young healthy male soccer players, who for 4-5 weeks had one leg immobilized in a cast. They were investigated before and after the cast period and after 4 weeks' physical training of the inactivated leg. Immobilization induced a significant increase in the subcutaneous thickness and a significant decrease in the circumference of the thigh (p less than 0.01). The calculated lean thigh volume was reduced from 4.93 1 to 4.10 1 (p less than 0.01), whereas the calculated fat thigh volume (1.5 1) was unchanged. The changes reversed after four weeks of progressive dynamic training, but did not reach the pre-immobilized values. Body weight decreased from 73.4 kg to 70.8 kg (p less than 0.01) during the immobilization period and was regained after the training period. The fat fraction of the body was unchanged. It is concluded that the loss in total thigh volume during inactivation in a cast is due to waste of the muscle tissue, and further that this loss is partly concealed by an unchanged fat thigh volume.