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Endurance training reduces the rate of diaphragm fatigue in vitro

Citation

Vrabas, IS and Dodd, SL and Powers, SK and Hughes, M and Coombes, JS and Fletcher, L and Demirel, HA and Reid, MB, Endurance training reduces the rate of diaphragm fatigue in vitro, Medicine & Science in Sports & Exercise, 31, (11) pp. 1605 - 1612. ISSN 0195-9131 (1999) [Refereed Article]

DOI: doi:10.1097/00005768-199911000-00017

Abstract

Purpose: The present study examined the effects of endurance training on the contractile and biochemical properties of the rat costal diaphragm in vitro. Methods: Sixty-four rats were divided into two groups: exercise trained (T) and control (C). Training consisted of treadmill running 5 d·wk -1 , 60 min·d -1 at ~70% of V̇O(2max), over a 10-wk period. Results: Control diaphragm strips produced an average of 12% less force from minute 15 to 50 of a 60-min in vitro fatigue protocol, compared with the T diaphragm strips (P < 0.01). T diaphragms had 10.1% higher citrate synthase (CS) and 12.1% higher superoxide dismutase (SOD) activities compared with the C (P < 0.05). Despite a significant decrease (P < 0.05) in Type IIb myosin heavy chains (MHC) and an increase (P < 0.05) in Type I MHC in T diaphragms, maximal shortening velocity (V(max)) in the diaphragm was not different between T and C animals. No differences were observed in specific force or the relative proportions of myosin light chains between groups. Conclusions: These findings suggest that endurance training reduces the rate of diaphragm fatigue in vitro but has no effect on V(max) or specific force.

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:17378
Year Published:1999
Web of Science® Times Cited:22
Deposited By:Secondary and Post-Compulsory Education
Deposited On:1999-08-01
Last Modified:2000-05-05
Downloads:0

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