Skeletal Muscle Respiratory Capacity, Endurance, and Glycogen Utilization

Document Type

Article

Language

eng

Publication Date

4-1975

Publisher

American Physiological Society

Source Publication

American Journal of Physiology

Source ISSN

0002-9513

Abstract

This study was undertaken to evaluate the relationship between physical performance capacity and the mitochondrial content of skeletal muscle. Four groups of rats were trained by means of treadmill running 5 days/wk for 13 wk. One group ran 10 min/day, a second group ran 30 min/day, a third group ran 60 min/day, and a fourth group ran 120 min/day. The magnitude of the exercise-induced adaptive increase in gastrocnemius muscle respiratory capacity varied over a twofold range in the four groups. There were significant correlations between the levels of three mitochondrial markers (cytochrome c, citrate synthase, respiratory capacity) in the animals' gastrocnemius muscles and the duration of a run to exhaustion. There was also a significant correlation between the amounts of glycogen remaining in liver and skeletal muscle after a 30-min-long exercise test and the respiratory capacity of the animal's leg muscles. These findings are compatible with the interpretation that a close relationship exists between skeletal muscle mitochondrial content and the capacity to perform endurance exercise.

Comments

American Journal of Physiology, Vol. 228, No. 4 (April 1975): 1029-1033. DOI.

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