Prevention of disuse muscle atrophy by means of electrical stimulation: maintenance of protein synthesis.

The effect of percutaneous electrical stimulation in preventing immobilisation-induced muscle atrophy was determined from measurements of quadriceps mass, composition, and rate of protein synthesis in seven men who had a fracture of one tibia immobilised in a long-leg cast for 6 weeks. These features were compared with those of fourteen men with similar injuries who did not use an electrical stimulator. In men who did not use the stimulator, quadriceps cross-sectional area (CSA) at midthigh, measured by ultrasonography, fell by a mean (SD) 17 (10)% and the rate of muscle protein synthesis was 23 (10)% lower on the immobilised than on the control side (0.037 [0.016] vs 0.048 [0.02]%/h). In contrast, in those who used the stimulator, quadriceps CSA (55.5 [7.3]) cm2 control leg, 50.9 [9.0] cm2 immobilised leg) and the rate of muscle protein synthesis (0.053 [0.009] %/h control leg, 0.059 [0.012] %/h immobilised leg) were similar on the two sides. The results suggest that brief periods of low-voltage percutaneous electrical stimulation will reduce quadriceps atrophy secondary to knee immobilisation, and that the mechanism includes prevention of the fall in muscle protein synthesis that usually occurs on immobilisation.