title: Sex differences in time to fatigue at 100% VO2 peak when normalized for fat free mass.
abstract: The purpose of this investigation was to compare sexes for time to fatigue at 100% VO(2)peak in recreationally trained individuals. Ten men (age: 23.4 ± 1.8; height: 177 ± 6.7; body mass: 83.8 ± 11.3; ± SD) and nine women (age: 25.0 ± 2.5; height: 165.6 ± 5.5; body mass: 62.7 ± 6.7) participated in this investigation after providing written consent. One week after assessing VO(2)peak, subjects exercised on an electrically braked cycle ergometer at 100% of VO(2)peak until fatigue. The time taken to fatigue was 48.9% longer for men than women (274 ± 13s vs. 184 ± 14s; p < 0.001, for men and women, respectively). When normalized for fat free mass (ffm; s/kg ffm) no significant differences between men and women were observed (3.99 ± 0.21s/kg ffm vs. 3.72 ± 0.28s/kg ffm for men and women, respectively, p = 0.431). The difference in fatigability between the sexes at this exercise intensity is to a large degree related to the difference in fat free mass.
authors.affiliation: The Exercise Physiology Laboratory, University of Louisville, Louisville, Kentucky, USA. CPLamb02@louisville.edu
authors.forename: Charles P
authors.initials: CP
authors.lastname: Lambert
authors.forename: Lee
authors.initials: L
authors.lastname: Winchester
authors.forename: Dean A
authors.initials: DA
authors.lastname: Jacks
authors.forename: Patrick Abi
authors.initials: PA
authors.lastname: Nader
mesh_terms: D000328:Adult; D001823:Body Composition; D005080:Exercise Test; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D012737:Sex Factors; D013997:Time Factors