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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1998-12-29
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pubmed:abstractText |
Soleus muscle fibers from the rat display a reduction in peak power and Ca2+ sensitivity after hindlimb suspension. To examine human responses to non-weight bearing, we obtained soleus biopsies from eight adult men before and immediately after 17 days of bed rest (BR). Single chemically skinned fibers were mounted between a force transducer and a servo-controlled position motor and activated with maximal (isotonic properties) and/or submaximal (Ca2+ sensitivity) levels of free Ca2+. Gel electrophoresis indicated that all pre- and post-BR fibers expressed type I myosin heavy chain. Post-BR fibers obtained from one subject displayed increases in peak power and Ca2+ sensitivity. In contrast, post-BR fibers obtained from the seven remaining subjects showed an average 11% reduction in peak power (P < 0.05), with each individual displaying a 7-27% reduction in this variable. Post-BR fibers from these subjects were smaller in diameter and produced 21% less force at the shortening velocity associated with peak power. However, the shortening velocity at peak power output was elevated 13% in the post-BR fibers, which partially compensated for their lower force. Post-BR fibers from these same seven subjects also displayed a reduced sensitivity to free Ca2+ (P < 0.05). These results indicate that the reduced functional capacity of human lower limb extensor muscles after BR may be in part caused by alterations in the cross-bridge mechanisms of contraction.
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pubmed:keyword | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
8750-7587
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
85
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1949-56
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:9804603-Adult,
pubmed-meshheading:9804603-Calcium,
pubmed-meshheading:9804603-Humans,
pubmed-meshheading:9804603-Isotonic Contraction,
pubmed-meshheading:9804603-Male,
pubmed-meshheading:9804603-Muscle, Skeletal,
pubmed-meshheading:9804603-Muscle Contraction,
pubmed-meshheading:9804603-Muscle Fibers, Skeletal,
pubmed-meshheading:9804603-Myosin Heavy Chains,
pubmed-meshheading:9804603-Rest
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pubmed:year |
1998
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pubmed:articleTitle |
Force-velocity-power and force-pCa relationships of human soleus fibers after 17 days of bed rest.
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pubmed:affiliation |
Department of Biology, Marquette University, Milwaukee, Wisconsin 53201, USA.
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pubmed:publicationType |
Journal Article,
Clinical Trial,
Research Support, U.S. Gov't, Non-P.H.S.
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