The critical threshold hypothesis proposes that performance fatigability during high-intensity exercise is tightly regulated by negative-feedback signals from the active muscles. We propose that performance fatigability is simply dependent on the exercise mode and intensity; the consequent adjustments, in skeletal muscle and the other physiological systems that support exercise, interact to modulate fatigue and determine exercise tolerance.
1Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom;
2Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa
Address for correspondence: Dr Kevin Thomas, Faculty of Health and Life Science, Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne, NE1 8ST, UK. Tel: +44 191 227 4863, Fax: +44 191 227 4713; Email: email@example.com
No funding was received for the work. The authors have no conflicts of interest to declare.