Effect of unloading on muscle volume with and without resistance training

Abstract

The present study aimed to investigate the effect of resistance training on the volume of four muscle groups and/or 17 individual muscles of the human lower limb during 20 days of 6 ∘ head-down tilt bed rest. Twelve healthy men were divided into two groups: the resistance training group: BR-Tr ( n = 6 ) and the control group: BR-Cont ( n = 6 ) . The volumes of the knee extensor, knee flexor, adductor, plantar flexor, and dorsiflexor muscle groups and their individual muscles were calculated. After the bed rest, the BR-Tr subjects showed no significant change in the volume in almost all tested muscles; in contrast, the volumes of the four muscle groups significantly decreased in the BR-Cont group ( - 12 % to - 8 %). These results suggest that resistance training during bed rest can prevent the deteriorating of thigh muscles and calf muscles.