Effect of unloading on muscle volume with and without resistance training

Hiroshi Akima, Jun ichi Ushiyama, Junjiro Kubo, Hideoki Fukuoka, Hiroaki Kanehisa, Tetsuo Fukunaga

Research output: Contribution to journalArticle

33 Citations (Scopus)


The present study aimed to investigate the effect of resistance training on the volume of four muscle groups and/or 17 individual muscles of the human lower limb during 20 days of 6{ring operator} head-down tilt bed rest. Twelve healthy men were divided into two groups: the resistance training group: BR-Tr (n = 6) and the control group: BR-Cont (n = 6). The volumes of the knee extensor, knee flexor, adductor, plantar flexor, and dorsiflexor muscle groups and their individual muscles were calculated. After the bed rest, the BR-Tr subjects showed no significant change in the volume in almost all tested muscles; in contrast, the volumes of the four muscle groups significantly decreased in the BR-Cont group (- 12% to - 8%). These results suggest that resistance training during bed rest can prevent the deteriorating of thigh muscles and calf muscles.

Original languageEnglish
Pages (from-to)728-736
Number of pages9
JournalActa Astronautica
Issue number8-9
Publication statusPublished - 2007 Apr
Externally publishedYes


  • Human
  • Microgravity
  • Muscle volume
  • Unloading

ASJC Scopus subject areas

  • Aerospace Engineering

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    Akima, H., Ushiyama, J. I., Kubo, J., Fukuoka, H., Kanehisa, H., & Fukunaga, T. (2007). Effect of unloading on muscle volume with and without resistance training. Acta Astronautica, 60(8-9), 728-736. https://doi.org/10.1016/j.actaastro.2006.10.006