Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles

Purpose: We have previously shown that the combination of low-intensity resistive exercise and moderate vascular occlusion induces in humans a marked increase in growth hormone secretion and muscular hypertrophy. The present study investigated the effects of vascular occlusion on the size of thigh muscles in patients who underwent an operation for the reconstruction of the anterior cruciate ligament to see whether it attenuates the disuse muscular atrophy without any exercise combined. Methods: Two sessions of occlusive stimulus, each consisting of five repetitions of vascular occlusion (mean maximal pressure, 238 mm Hg) for 5 min and the release of occlusion for 3 min, were applied daily to the proximal end of the thigh from 3rd to 14th days after the operation. Changes in the cross-sectional area (CSA) of thigh muscles were analyzed with magnetic resonance images taken on the 3rd and 14th day after the operation. Results: Without occlusive stimulus (control), the CSAs of knee extensors and flexors decreased by 20.7 ± 2.2% and 11.3 ± 2.6% (mean ± SEM, N = 8), whereas with the occlusive stimulus, they decreased by 9.4 ± 1.6% and 9.2 ± 2.6% (N = 8), respectively. The relative decrease in CSA of knee extensors was significantly (P < 0.05) larger in the control group than in the experimental group. Conclusion: The results indicate that the occlusive stimulus effectively diminishes the postoperation disuse atrophy of knee extensors.