At the start of rehabilitation, muscle volume was significantly smaller (860 ml, 16 per cent) in the injured than in the uninjured leg. By the end of rehabilitation (mean 50 days) the injured leg had siginficantly increased by 360 ml (8 per cent) over its initial volume, and the uninjured one had increased but not significantly (120 ml, 2 per cent), so that the injured leg was still approximately 11 per cent (620 ml) small than the uninjured. The initial degree of atrophy and the period of immobilization were not significantly correlated, although the latter showed a negative relationship (P greater than 0.05) with the rate of increase of muscle volume in the injured leg. No significant correlation was found between the ratio of injured/uninjured leg volumes and muscle width measurements at 1/3 subischial, at 12.7 cm above the knee joint space or at the maximum calf. In systematic studies involving atrophy muscle volume must therefore be estimated either by anthropometry or by X-ray measurements.
Professor Anthony J Sargeant carried out this research as part of his PhD in the early 1970s. It demonstrated that simple measurements of thigh muscle girth were fairly useless in assessing the magnitude of gross muscle atrophy and loss due to immobilization following leg fracture. In fact a subsequent study (published in Clinical Science by Anthony Sargeant in 1977) showed that even detailed anthropometric or X-ray measurements of muscle size greatly underestimated the actual loss at the muscle fibre level.
Effects of exercise therapy on total and component tissue leg volumes of patients undergoing rehabilitation from lower limb injury
Annals of Human Biology. 1975 Oct;2(4):327-37