Resistive vibration exercise reduces lower limb muscle atrophy during 56-day bed-rest.

OBJECTIVES The current study aimed to examine the effectiveness of a resistive vibration exercise countermeasure during prolonged bed-rest in preventing lower-limb muscle atrophy. METHODS 20 male subjects underwent 56-days of bed-rest and were assigned to either an inactive control, or a countermeasure group which performed high-load resistive exercises (including squats, heel raises and toe raises) with whole-body vibration. Magnetic resonance imaging of the lower-limbs was performed at two-weekly intervals. Volume of individual muscles was calculated. RESULTS Countermeasure exercise reduced atrophy in the triceps surae and the vastii muscles (F>3.0, p<.025). Atrophy of the peroneals, tibialis posterior and toe flexors was less in the countermeasure-subjects, though statistical evidence for this was weak (For=.071). Atrophy in the hamstring muscles was similar in both groups (F<1.1, p>.38). The adductor longus, sartiorius and rectus femoris muscles showed little loss of muscle volume during bed-rest (F<1.7, p>.15). CONCLUSIONS The countermeasure exercise programme was effective in reducing atrophy in the extensors of the knee and ankle but not the hamstrings.