title: Constraints on muscular performance: trade-offs between power output and fatigue resistance.
abstract: An important functional and evolutionary constraint on the physical performance of vertebrates is believed to be the trade-off between speed and endurance capacity. However, despite the pervasiveness of physiological arguments, most studies have found no evidence of the trade-off when tested at the whole-animal level. We investigated the existence of this trade-off at the whole-muscle level, the presumed site of this physiological conflict, by examining inter-individual variation in both maximum power output and fatigue resistance for mouse extensor digitorum longus (EDL) muscle using the work-loop technique. We found negative correlations between several measures of in vitro maximum power output and force production with fatigue resistance for individual mouse EDL muscles, indicating functional trade-offs between these performance parameters. We suggest that this trade-off detected at the whole-muscle level has imposed an important constraint on the evolution of vertebrate physical performance.
authors.affiliation: Department of Zoology and Entomology, The University of Queensland, St Lucia, QLD 4072, Australia. rwilson@zen.uq.edu.au
authors.forename: Robbie S
authors.initials: RS
authors.lastname: Wilson
authors.forename: Rob S
authors.initials: RS
authors.lastname: James
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004558:Electric Stimulation; D005260:Female; D051379:Mice; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D013997:Time Factors