title: Absence of an effect of fatigue on muscle efficiency during high-intensity exercise in rat skeletal muscle.
abstract: The effect of fatigue was studied on rat skeletal muscle efficiency during maximal dynamic exercise of 10s duration. After the initial 4s of exercise, power output decreased rapidly to 46.2 +/- 6.7% (mean +/- SD; n = 6) after 6s of stimulation and further to 17.5 +/- 5.8% in the last contraction. Both the rates of total work output and high-energy phosphate consumption decreased with increasing exercise duration. As a result muscle efficiency was not affected by exercise time in the present experiments. This result indicates that fatigue in severe maximal exercise is induced by a feed-back mechanism, which in the case of high ATP utilisation rates will reduce ATP splitting probably by reducing Ca(2+)-release from the sarcoplasmic reticulum.
authors.affiliation: Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije University, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: de Haan
authors.forename: J C
authors.initials: JC
authors.lastname: Koudijs
authors.forename: E
authors.initials: E
authors.lastname: Verburg
mesh_terms: D000818:Animals; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors