Muscle hypertrophy induced by heat-stress with low-intensity exercise in healthy humans
- Paper number
IAC-06-A1.3.07
- Author
Dr. Toshitada Yoshioka, Hirosaki Gakuin University, Japan
- Coauthor
Dr. Atsushi Kojima, Japan
- Coauthor
Dr. Shigeta Morioka, Japan
- Coauthor
Dr. Toshihito Naito, Japan
- Coauthor
Dr. Takao Sugiura, Yamaguchi University, Japan
- Coauthor
Prof. Katsumasa Goto, Japan
- Year
2006
- Abstract
Establishment of a countermeasure for muscle atrophy induced by inactivity is important task for space development. We have shown that heat stress induces muscle hypertrophy and is a useful tool for a countermeasure for muscle atrophy in cell culture as well as animal studies. However, there is no evidence regarding heat stress-associated muscle hypertrophy in human. The purpose of this study was to investigate the effects of low-intensity exercise (LIE) with heat-stress on muscle hypertrophy. Five healthy men were subjected to 10 weeks LIE for elbow flexor muscles, in which 4 days a week at less than 30 repetition maximum (RM), performing 3 sets (20 repetitions) of flexion-extension exercise of elbow joint of left non-dominant hand. Application of heat-stress was performed at the same time as elbow exercise on upper left arm by using a heating pad for 2 sets of 30 min with 5 min-interval. We have confirmed that the temperature of biceps brachii muscles increased up to 38 ∘C after the heating procedure used in the present study. Maximum isometric force in flexion significantly increased 13.8% in trained arm and 10.0% in untrained arm after LIE (p<0.05). Significant increment (12.0%) in the mean cross-sectional area of biceps brachii muscles in left arm was observed (p<0.05). Evidences strongly indicated that exercise training at an intensity even lower than 50% 1 RM could be effective in increasing in muscle strength with muscle hypertrophy when combined with heating. These results suggest that heat stress-associated muscle hypertrophy might be a useful countermeasure for muscular atrophy during space flight as well as rehabilitation.
- Abstract document
- Manuscript document
IAC-06-A1.3.07.pdf (🔒 authorized access only).
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