Comparison of a space shuttle flight (STS-78) and bed rest on human muscle function
1 Human Performance Laboratory, Ball State University, Muncie, Indiana 47306; and 2 Biology Department, Marquette University, Milwaukee, Wisconsin 53201 The purpose of this investigation was to assess muscle fiber size, composition, and in vivo contractile characteristics of the calf muscle of fou...
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Veröffentlicht in: | Journal of applied physiology (1985) 2001-07, Vol.91 (1), p.57-64 |
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Zusammenfassung: | 1 Human Performance Laboratory, Ball State University,
Muncie, Indiana 47306; and 2 Biology Department, Marquette
University, Milwaukee, Wisconsin 53201
The purpose of this investigation was to assess
muscle fiber size, composition, and in vivo contractile characteristics
of the calf muscle of four male crew members during a 17-day
spaceflight (SF; Life and Microgravity Sciences Spacelab Shuttle
Transport System-78 mission) and eight men during a 17-day bed rest
(BR). The protocols and timelines of these two investigations were
identical, therefore allowing for direct comparisons between SF and the
BR. The subjects' age, height, and weight were 43 ± 2 yr,
183 ± 4 cm, and 86 ± 3 kg for SF and 43 ± 2 yr,
182 ± 3 cm, and 82 ± 4 kg for BR, respectively. Calf muscle
strength was examined before SF and BR; on days 2, 8 , and
12 during SF and BR; and on days 2 and
8 of recovery. Muscle biopsies were obtained before and within 3 h after SF (gastrocnemius and soleus) and BR (soleus) before reloading. Maximal isometric calf strength and the
force-velocity characteristics were unchanged with SF or BR.
Additionally, neither SF nor BR had any effect on fiber composition or
fiber size of the calf muscles studied. In summary, no changes in calf
muscle strength and morphology were observed after the 17-day SF and BR. Because muscle strength is lost during unloading, both
during spaceflight and on the ground, these data suggest that the
testing sequence employed during the SF and BR may have served as a
resistance training countermeasure to attenuate whole muscle strength loss.
spaceflight; skeletal muscle; weightlessness; unloading; Shuttle
Transport System-78 |
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ISSN: | 8750-7587 1522-1601 |
DOI: | 10.1152/jappl.2001.91.1.57 |