Document Detail

Muscle volume, strength, endurance, and exercise loads during 6-month missions in space.
MedLine Citation:
PMID:  20131648     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Decrements in muscular strength during long-duration missions in space could be mission-critical during construction and exploration activities. The purpose of this study was to quantify changes in muscle volume, strength, and endurance of crewmembers on the International Space Station (ISS) in the context of new measurements of loading during exercise countermeasures. METHODS: Strength and muscle volumes were measured from four male ISS crewmembers (49.5 +/- 4.7 yr, 179.3 +/- 7.1 cm, 85.2 +/- 10.4 kg) before and after long-duration spaceflight (181 +/- 15 d). Preflight and in-flight measurements of forces between foot and shoe allowed comparisons of loading from 1-g exercise and exercise countermeasures on ISS. RESULTS: Muscle volume change was greater in the calf (-10 to 16%) than the thigh (-4% to -7%), but there was no change in the upper arm (+0.4 to -0.8%). Isometric and isokinetic strength changes at the knee (range -10.4 to -24.1%), ankle (range -4 to -22.3%), and elbow (range -7.5 to -16.7%) were observed. Although there was an overall postflight decline in total work (-14%) during the endurance test, an increase in postflight resistance to fatigue was observed. The peak in-shoe forces during running and cycling on ISS were approximately 46% and 50% lower compared to 1-g values. DISCUSSION: Muscle volume and strength were decreased in the lower extremities of crewmembers during long-duration spaceflight on ISS despite the use of exercise countermeasures. in-flight countermeasures were insufficient to replicate the daily mechanical loading experienced by the crewmembers before flight. Future exercise protocols need careful assessment both in terms of intensity and duration to maximize the "dose" of exercise and to increase loads compared to the measured levels.
Raghavan Gopalakrishnan; Kerim O Genc; Andrea J Rice; Stuart M C Lee; Harlan J Evans; Christian C Maender; Hakan Ilaslan; Peter R Cavanagh
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  81     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-02-05     Completed Date:  2010-03-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  91-102     Citation Subset:  IM; S    
Department of Biomedical Engineering , Cleveland Clinic, Cleveland, OH, USA.
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MeSH Terms
Ankle Joint / physiology
Exercise / physiology*
Extraterrestrial Environment*
Magnetic Resonance Imaging
Middle Aged
Muscle Strength / physiology*
Muscle, Skeletal / pathology
Muscular Atrophy / etiology
Physical Endurance / physiology*
Range of Motion, Articular
Space Flight*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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