The Effect of Percussive Massage on The Maintenance of Skeletal Muscle Health During Limb Unloading

A period of skeletal muscle disuse, even as short as 7 days, can result in a loss of muscle mass and strength, along with declines in metabolic health. Several studies suggest that passive mechanical stimulation may provide protection against these detrimental effects of skeletal muscle disuse. Objective: The present study assessed the efficacy of twice-daily percussive massage for mitigating the adverse effects of muscle disuse during 10 days of leg unloading. Hypothesis: It was hypothesized that those in the massage group would experience less skeletal muscle atrophy and strength loss, smaller declines in mitochondrial function, and less hydrogen peroxide flux. Methods: 17 participants (7 women and 10 men; 18-35 yrs) were randomly assigned to either a control or massage group, both undergoing single-leg unloading through the use of a knee brace and crutches. Results: Both groups experienced similar reductions in maximal isometric strength (-14%±5.9; p<.0001), quadriceps volume (-4.2% ± 2.8; p<.0001), myofiber cross-sectional area (-8.2% ± 1.8; p<.0001), and maximal mitochondrial respiration (-20%±9.1; p<.0001). Fatty acid-supported respiration decreased only in the control group (-30.4 ± 18.5%; p = 0.0008). Hydrogen peroxide (H 2 O 2 ) flux normalized to oxygen consumption exhibited a significant interaction between group and time, particularly in the absence of ADP, where H 2 O 2 flux increased only in the control group (control: 29.9 ± 26.5%, massage: -13 ± 22.6%; p=0.01). There was no change in the H 2 O 2 flux after the addition of ADP. Conclusions: 10 days of leg unloading resulted in significant reductions in muscle size, strength, and mitochondrial respiration. While percussive massage was ineffective in preventing the loss of muscle mass, force production, or carbohydrate-supported respiration, it showed potential in mitigating the decline in mitochondrial fatty acid-supported respiration. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.