High force contractions as a countermeasure to muscle atrophy /
The purpose of this study was to test the hypotheses that (1) high stress eccentric contractions performed periodically by mouse triceps surae muscles during hind limb suspension would minimize atrophy and the accompanying functional loss, and (2) the extent of the attenuation of atrophy and functio...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2003.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765867231&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The purpose of this study was to test the hypotheses that (1) high stress eccentric contractions performed periodically by mouse triceps surae muscles during hind limb suspension would minimize atrophy and the accompanying functional loss, and (2) the extent of the attenuation of atrophy and functional loss would be proportional to the forces produced by the muscles. A nerve cuff was implanted on the left tibial nerve in 49 adult female ICR mice. The mice were allowed to recover for 4 wk and assigned to 6 groups: 1) normal cage activity, 2) hind limb-suspended and no countermeasure, 3) hind limb-suspended and isometrically trained at 100% of maximal isometric torque (MT), 4) hind limb-suspended and isometrically trained at 80% of MT, 5) hind limb-suspended and eccentrically trained at 140% of MT, and 6) hind limb-suspended and eccentrically trained at 100% of MT. All mice were anesthetized every other day during the 10 d suspension, and, in addition, the countermeasure groups were trained in vivo every other day (30 contractions/bout). In vivo frequency- and velocity-dependent torque measurements were made on the plantar flexors both before and after the 10 d suspension. Despite a loss in gastrocnemius muscle wet weight (19%) in the untrained suspended mice, the suspension did not cause a loss in strength in the planar flexor group. Soleus muscle wet weight (-26%) and maximal isometric tetanic force (-30%) were decreased in the untrained suspended mice. Surprisingly, there was no attenuation of loss in muscle weight or strength of the soleus muscle in any of the countermeasure groups. The failure to see any effects of training suggests that the volume of training was insufficient as a countermeasure in this species. |
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| Item Description: | Vita. "Major Subject: Kinesiology". |
| Physical Description: | vi, 92 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 55-69). |