QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Armstrong, R. Articles by Taylor, C. Search for Related Content PubMed Articles by Armstrong, R. Articles by Taylor, C. Social Bookmarking                         What's this?

Journal of Experimental Biology, Vol 97, Issue 1 411-420, Copyright © 1982 by Company of Biologists

JOURNAL ARTICLES

Relationship between muscle force and muscle area showing glycogen loss during locomotion

RB Armstrong and CR Taylor

This experiment was designed to study the relationship between the cross-sectional area of rat skeletal muscle showing glycogen loss and the muscle forces exerted during exercise. Muscular force exerted by the extensors of the elbows and ankle was increased by 24% by loading rats with 24% of their body mass while running them on a treadmill at 30 m.min-1. VO2 increased by 24% and stride frequency was unchanged when the rats ran with loads. Cross-sectional areas of the elbow and ankle extensor muscles showing glycogen loss were compared from rats running with and without the load. We found a nearly direct proportionality between the changes in force and the changes in muscle area showing glycogen loss, i.e. when the force of the extensors was increased by 24%, the cross-sectional area of the elbow extensors showing glycogen loss increased by 28%, and that of the ankle extensor group increased by 24%. The more peripheral muscles in each group accounted for a greater proportion of the increase in cross-sectional area of the group showing glycogen loss (i.e. lateral and long heads of triceps brachii muscle accounted for 91% of the increase in the elbow extensor group, and gastrocnemius muscle accounted for 84% of the increase in the ankle extensor group). Most of the increases in muscle area showing glycogen loss occurred in fast-twitch-glycolytic fibres (84% in the elbow and 88% in the ankle). The data suggest that increasing muscle force requirements by 24% by loading resulted in proportional increases in cross-sectional area of muscles recruited to produce the force, i.e. that spatial recruitment primarily accounted for the elevation in force. The relatively greater increases in cross-sectional area showing glycogen loss of peripheral muscles within a group indicate the importance of studying whole groups of muscles when considering muscular recruitment patterns during exercise.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				L. C Rome The effect of temperature and thermal acclimation on the sustainable performance of swimming scup Phil Trans R Soc B, November 29, 2007; 362(1487): 1995 - 2016. [Abstract] [Full Text] [PDF]

				T. M. Griffin, T. J. Roberts, and R. Kram Metabolic cost of generating muscular force in human walking: insights from load-carrying and speed experiments J Appl Physiol, July 1, 2003; 95(1): 172 - 183. [Abstract] [Full Text] [PDF]

				L. Rome and D. Swank The influence of thermal acclimation on power production during swimming. I. In vivo stimulation and length change pattern of scup red muscle J. Exp. Biol., January 2, 2001; 204(3): 409 - 418. [Abstract] [PDF]

				D Swank and L Rome The influence of thermal acclimation on power production during swimming. II. Mechanics of scup red muscle under in vivo conditions J. Exp. Biol., January 2, 2001; 204(3): 419 - 430. [Abstract] [PDF]

				D. Swank and L. Rome The influence of temperature on power production during swimming. I. In vivo length change and stimulation pattern J. Exp. Biol., January 1, 2000; 203(2): 321 - 331. [Abstract] [PDF]