Computerized tomographic determination of human thigh components. The effects of immobilization in plaster and subsequent physical training.

Thigh components were estimated by computerized tomography (CT) as well as by anthropometry in two healthy male soccer players (23--29 years), who for 5 weeks had one knee immobilized in a plaster of Paris. The investigations were performed on both thighs just after removal of the cast and after 5 weeks physical training of the inactivated quadriceps muscle. The different components were easily identified on a transverse scan through the middle of the thigh. The quadriceps muscle was 26% smaller after removal of the cast in the inactivated leg as compared with the contralateral leg; no differences were observed in the remaining thigh components. After rehabilitation a specific increase (22%) in the hypotrofic quadriceps muscle was observed, whereas no changes were disclosed in the remaining thigh components. The quadriceps muscle averaged 52% of the lean component in the uninjured thigh, and the subcutaneous part of the total cross-sectional area averaged 15%. The changes in the anthropometrically determined thigh components paralleled those observed by the CT scanning procedure. It is concluded that the loss in the lean thigh volume during immobilization in plaster cast is exclusively due to waste of the quadriceps muscle. CT scanning comprises a new valid tool to study changes in thigh components.