Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles

Purpose: We have previously shown that the combination of low-intensity res istive 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 m uscles in patients who underwent an operation for the reconstruction of the anterior cruciate ligament to see whether it attenuates the disuse muscula r 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 m in, were applied daily to the proximal end of the thigh from 3rd to 14th da ys after the operation. Changes in the cross-sectional area (CSA) of thigh muscles were analyzed with magnetic resonance images taken on the 3rd and 1 4th 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 relat ive decrease in CSA of knee extensors was significantly (P < 0.05) larger i n the control group than in the experimental group. Conclusion: The results indicate that the occlusive stimulus effectively diminishes the postoperat ion disuse atrophy of knee extensors.