Document Detail


Self-generated lower body negative pressure exercise.
MedLine Citation:
PMID:  10332951     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Exercise during spaceflight helps prevent musculoskeletal and cardiovascular deconditioning to Earth gravity. This report evaluates the aerobic and anaerobic exercise stimulus provided by self-generated lower body negative pressure. METHODS: A lower body negative pressure cylinder expands and collapses longitudinally, but not radially. As the legs push footward to expand the cylinder, the air pressure in the cylinder decreases, increasing the force required to continue expanding the cylinder. In addition, valves control air flow into and out of the cylinder, and thus workload. In seven supine subjects, knee bend exercise was performed at 19 cycles per minute for 6 min. Footward force was measured with load cells, cylinder pressure with a transducer, heart rate from ECG, and oxygen consumption with turbine volumetry and gas analysis. RESULTS: Maximum footward force at the peak of the exercise cycle averaged 1120+/-88 N (114+/-9 kg), and pressure within the cylinder concomitantly decreased 26+/-3 mmHg below ambient. Heart rate and oxygen consumption increased 75+/-4 bpm and 26.3+/-1.4 ml O2/kg x min(-1) from supine resting values, respectively. CONCLUSIONS: With the air inlet valve nearly closed, exercise with this device approximates a resistance-type leg press. With more inflow of air, more rapid, aerobic knee bends can be performed. This exercise device/concept provides simultaneous dynamic musculoskeletal and cardiovascular stresses without an external power source.
Authors:
D E Watenpaugh; R E Ballard; G A Breit; A R Hargens
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  70     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  1999 May 
Date Detail:
Created Date:  1999-07-07     Completed Date:  1999-07-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  522-6     Citation Subset:  IM; S    
Affiliation:
Life Science Division, NASA Ames Research Center, Moffett Field, CA, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Equipment Design
Exercise Test
Exercise Therapy / instrumentation,  methods*
Female
Humans
Lower Body Negative Pressure / instrumentation,  methods*
Male
Middle Aged
Monitoring, Physiologic
Oxygen Consumption
Space Flight*
Supine Position
Weight-Bearing
Weightlessness / adverse effects*
Investigator
Investigator/Affiliation:
A R Hargens / ARC

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


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