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.