Low-intensity exercise can increase muscle mass and strength proportionally to enhanced metabolic stress under ischemic conditions

Shingo Takada, Koichi Okita, Tadashi Suga, Masashi Omokawa, Tomoyasu Kadoguchi, Takashi Sato, Masashige Takahashi, Takashi Yokota, Kagami Hirabayashi, Noriteru Morita, Masahiro Horiuchi, Shintaro Kinugawa, Hiroyuki Tsutsui

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60 Citations (Scopus)


Skeletal muscle bulk and strength are becoming important therapeutic targets in medicine. To increase muscle mass, however, intensive, long-term mechanical stress must be applied to the muscles, and such stress is often accompanied by orthopedic and cardiovascular problems. We examined the effects of circulatory occlusion in resistance training combined with a very low-intensity mechanical load on enhancing muscular metabolic stress and thereby increasing muscle bulk. Muscular metabolic stress, as indicated by the increases in inorganic phosphate (Pi) and a decrease in intramuscular pH, was evaluated by 31P-magnetic resonance spectroscopy during unilateral plantar-flexion at 20% of the one-repetition maximum (1-RM) with circulatory occlusion for 2 min in 14 healthy, male untrained participants (22 yr) at baseline. Participants performed two sets of the same exercise with a 30-s rest between sets, 2 times/day, 3 days/wk, for 4 wk. The muscle cross-sectional area (MCA) of the plantar-flexors and the 1-RM were measured at baseline and after 2 and 4 wk of training. MCA and 1-RM were significantly increased after 2 and 4 wk (P < 0.05, respectively). The increase in MCA at 2 wk was significantly (P < 0.05) correlated with the changes in Pi (r = 0.876) and intramuscular pH (r = 0.601). Furthermore, the increases in MCA at 4 wk and 1-RM at 2 wk were also correlated with the metabolic stress. Thus enhanced metabolic stress in exercising muscle is a key mechanism for favorable effects by resistance training. Low-intensity resistance exercise provides successful outcomes when performed with circulatory occlusion, even with a short training period.

Original languageEnglish
Pages (from-to)199-205
Number of pages7
JournalJournal of Applied Physiology
Issue number2
Publication statusPublished - Jul 15 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)


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