HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 93/7/843    most recent expphysiol.2007.041764v1 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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Wüst, R. C. I. Articles by Degens, H. PubMed PubMed Citation Articles by Wüst, R. C. I. Articles by Degens, H. Related Collections Muscle

¹ Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, John Dalton Building, Chester Street, Manchester, UK ² Research institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands ³ School of Sport and Exercise Sciences, the University of Birmingham, Birmingham, UK

To explore the cause of higher skeletal muscle fatigue resistance in women than men, we used electrically evoked contractions (1 s on, 1 s off, 30 Hz, 2 min), which circumvent motivational bias and allow examination of contractile properties. We compared 29 men [26.5 (7.0) years old; mean (S.D.)] with 35 women [25.4 (7.6) years old]. Strength of the quadriceps muscle was higher in men than women (P < 0.001). The lower maximal rate of relaxation in women (P = 0.002) indicates that their muscles were slower than those of men. The torque declined less in women than in men [37.7 (10.7) versus 29.9 (10.0)%; P = 0.002], and was not related to muscle strength or size, as determined with magnetic resonance imaging. The sex difference in fatigability was also seen when the circulation to the leg was occluded [torque declined 76.9 (10.8) versus 59.5 (16.9)% in men versus women, respectively; P = 0.008]. The maximal rate of relaxation correlated with the fatigability of the muscle under all conditions (correlations ranging from 0.34 to 0.51, P < 0.02). We conclude that the sex-related difference in skeletal muscle fatigue resistance is not explicable by differences in motivation, muscle size, oxidative capacity and/or blood flow between sexes, but might be related to differences in fibre type composition.

(Received 18 December 2007; accepted after revision 22 February 2008; first published online 22 February 2008)
Corresponding author R. C. I. Wüst: Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, John Dalton Building, Chester Street, Manchester, M1 5GD, UK. Email: r.wust{at}mmu.ac.uk