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Models of disuse - A comparison of hindlimb suspension and immobilizationThe effects of 1 and 2 weeks of hindlimb suspension (HS) on the contractile properties of fast- and slow-twitch skeletal muscles of male Sprague Dawley rats are studied and compared with hindlimb immobilization (HI) data. The optimal length and contractile properties of the slow-twitch soleus, fast-twitch extensor digitorum longus, and the vastus lateralis are measured. It is observed that HS and HI affect slow-twitch muscles; isometric twitch duration in the slow-twitch soleus is decreased. Soleus muscle mass and peak tetanic tension declines with disuse. A major difference in the influence of HS and HI on the maximal speed of soleus muscle shortening, V(max) is detected; HS produced a twofold increase in V(max) compared to control data and HI had no significant effect on V(max). The relation between V(max) and myosin concentration is analyzed. The data reveal that HS modifies slow-twitch muscle yielding hybrid fibers with elevated shortening velocities and this change may be dependent on the elimination of load-bearing contractions.
Document ID
19860059458
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Fitts, R. H.
(Marquette Univ. Milwaukee, WI, United States)
Metzger, J. M.
(Marquette Univ. Milwaukee, WI, United States)
Riley, D. A.
(Marquette Univ. Milwaukee, WI, United States)
Unsworth, B. R.
(Marquette University; Wisconsin, University, Milwaukee, United States)
Date Acquired
August 12, 2013
Publication Date
June 1, 1986
Publication Information
Publication: Journal of Applied Physiology
Volume: 60
ISSN: 0161-7567
Subject Category
Life Sciences (General)
Accession Number
86A44196
Funding Number(s)
CONTRACT_GRANT: NCC2-266
CONTRACT_GRANT: NAG2-212
Distribution Limits
Public
Copyright
Other

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