title: Are There Critical Fatigue Thresholds? Aggregated vs. Individual Data.
abstract: The mechanisms underlying task failure from fatiguing physical efforts have been the focus of many studies without reaching consensus. An attractive but debated model explains effort termination with a critical peripheral fatigue threshold. Upon reaching this threshold, feedback from sensory afferents would trigger task disengagement from open-ended tasks or a reduction of exercise intensity of closed-ended tasks. Alternatively, the extant literature also appears compatible with a more global critical threshold of loss of maximal voluntary contraction force. Indeed, maximal voluntary contraction force loss from fatiguing exercise realized at a given intensity appears rather consistent between different studies. However, when looking at individual data, the similar maximal force losses observed between different tasks performed at similar intensities might just be an "artifact" of data aggregation. It would then seem possible that such a difference observed between individual and aggregated data also applies to other models previously proposed to explain task failure from fatiguing physical efforts. We therefore suggest that one should be cautious when trying to infer models that try to explain individual behavior from aggregated data.
authors.affiliation: Institute of Sport Sciences, University of LausanneLausanne, Switzerland; Department of Physiology, Faculty of Biology and Medicine, University of LausanneLausanne, Switzerland.
authors.forename: Daria
authors.initials: D
authors.lastname: Neyroud
authors.affiliation: Institute of Sport Sciences, University of LausanneLausanne, Switzerland; Department of Physiology, Faculty of Biology and Medicine, University of LausanneLausanne, Switzerland.
authors.forename: Bengt
authors.initials: B
authors.lastname: Kayser
authors.affiliation: Institute of Sport Sciences, University of LausanneLausanne, Switzerland; Department of Physiology, Faculty of Biology and Medicine, University of LausanneLausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Place
keywords: critical threshold; endurance performance; maximal voluntary contraction; neuromuscular fatigue; peak twitch; task failure