Massage as an Intervention for Muscle Atrophy

The loss of muscle mass during disease states is an important determinant of morbidity and mortality, and finding interventions that will decrease atrophy is therefore of great importance. Our previous studies showed that massage attenuated atrophy and aided in regrowth of skeletal muscle through enhanced protein synthesis induction in an animal model. We now present preliminary data that indicate the same effect in humans in an experimental model of muscle atrophy. In addition, a cross-over effect of massage to the non-massaged limb was observed and this will be further investigated in humans. We hypothesize that the mechanical action of massage on muscle will enhance protein synthesis and attenuate atrophy and that the contralateral limb will benefit through a cross over effect. Mechanisms underlying these beneficial responses will be investigated. We will use volunteers who will either serve as controls or will undergo unilateral lower limb suspension (ULLS) with or without massage on the left vastus lateralis muscle. Subjects will ingest deuterium oxide for measurement of protein, RNA and DNA synthesis in the massaged as well as contralateral muscle. Vastus lateralis muscle will be massaged using an instrumented rolling device allowing accurate application of standardized loads. There will be three groups of subjects: (1) controls who will not undergo ULLS and will receive massage on left leg, (2) subjects undergoing ULLS of the left leg without massage, and (3) subjects undergoing ULLS of the left leg with massage every other day for 4 bouts during a 7 day period. Baseline biopsies will be taken at the beginning of the experiments and 7 days later 4-6 hours after the last bout of massage. Protein, RNA and DNA synthesis, muscle cross sectional area as well as intracellular signaling pathways and cellular responses, such as muscle stem cell activation, will be determined. Results will indicate whether massage can be used as an intervention for the loss of muscle mass during an atrophying event. This novel idea is of high clinical significance as massage could be used to inhibit the loss of muscle size in patients unable to undergo traditional rehabilitation, such as those in intensive care units and non-weight bearing after orthopedic surgery. In addition, identifying mechanisms by which massage enhances muscle size and increases protein synthesis will inform us how to improve this beneficial response.