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Exercise-induced alterations in skeletal muscle myosin heavy chain phenotype: dose-response relationship

Citation

Demirel, HA and Powers, SK and Naito, H and Hughes, M and Coombes, JS, Exercise-induced alterations in skeletal muscle myosin heavy chain phenotype: dose-response relationship, Journal of Applied Physiology, 86, (3) pp. 1002-1008. ISSN 8750-7587 (1999) [Refereed Article]

DOI: doi:10.1152/jappl.1999.86.3.1002

Abstract

This study investigated the effects of exercise training duration on the myosin heavy chain (MHC) isoform distribution in rat locomotor muscles. Female Sprague-Dawley rats (120 days old) were assigned to either a sedentary control group or to one of three endurance exercise training groups. Trained animals ran on a treadmill at ~75% maximal O 2 uptake for 10 wk (4-5 days/wk) at one of three different exercise durations (30, 60, or 90 min/day). Training resulted in increases (P < 0.05) in citrate synthase activity in the soleus and extensor digitorum longus in both the 60 and 90 min/day duration groups and in the plantaris (Pla) in all three exercise groups. All durations of training resulted in a reduction (P < 0.05) in the percentage of MHC(IIb) and an increase (P < 0.05) in the percentage of MHC(IIa) in the Pla. The magnitude of change in the percentage of MHC(IIb) in the Pla increased as a function of the training duration. In the extensor digitorum longus, 90 min of daily exercise promoted a decrease (P < 0.05) in percentage of MHC(IIb) and increases (P < 0.05) in the percentages of MHC(I), MHC(IIa), and MHC(IId/x). Finally, training durations ≥60 min resulted in an increase (P < 0.05) in the percentage of MHC(I) and a concomitant decrease (P < 0.05) in the percentage of MHC(IIa) in the soleus. These results demonstrate that increasing the training duration elevates the magnitude of the fast-to-slow shift in MHC phenotype in rat hindlimb muscles.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Human Movement and Sports Science
Research Field:Exercise Physiology
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Skeletal System and Disorders (incl. Arthritis)
Author:Coombes, JS (Dr Jeff Coombes)
ID Code:17126
Year Published:1999
Web of Science® Times Cited:81
Deposited By:Secondary and Post-Compulsory Education
Deposited On:1999-08-01
Last Modified:2011-08-05
Downloads:0

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