Document Detail

Gravity replacement during running in simulated microgravity.
MedLine Citation:
PMID:  17086763     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: During treadmill exercise on the International Space Station (ISS), a restoring load from a subject load device (SLD) is applied through a shoulder-and-waist harness to pull the exercising crewmember toward the treadmill surface. The capacity of this arrangement to provide 1-g-like reaction forces may be critical for effective use of the treadmill as a countermeasure to musculoskeletal changes during prolonged spaceflight. This study in simulated microgravity evaluated the comfort and function during running of the ISS harness used with a new SLD in a system that allows more even distribution of the load between the waist and shoulders. METHODS: Using a zero-gravity locomotion simulator, 12 subjects completed three 5-min running trials at a constant speed (3.35 m x s(-1)) using three SLD loads [50%, 75%, and 100% of bodyweight (BW)] presented at random and a shoulder-to-waist loading ratio of 50:50. Subjective ratings of discomfort, ground reaction forces (GRFs), and SLD loads were collected. RESULTS: A load of 100% BW resulted in similar GRF profiles (peak and rate of change of force) to those reported for 1-g running over ground and were also comfortably tolerated (mean Borg scale rating 3.9/10). DISCUSSION: With an appropriate harness and SLD system, 1-g-like GRF profiles can be generated at the feet during simulated microgravity running. Such forces can be achieved with a level of discomfort rated better than "somewhat uncomfortable," suggesting that running with 1-g loads could be an effective component of musculoskeletal countermeasures during long-duration spaceflight.
Kerim O Genc; Vince E Mandes; 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:  77     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2006 Nov 
Date Detail:
Created Date:  2006-11-07     Completed Date:  2007-01-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1117-24     Citation Subset:  IM; S    
Department of Biomedical Engineering, The Cleveland Clinic, Cleveland, OH 44195, USA.
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MeSH Terms
Exercise / physiology*
Running / physiology*
Space Flight
Weight-Bearing / physiology
Weightlessness Countermeasures*
Weightlessness Simulation*

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

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