Interaction of Factors Determining Critical Power
Open Access
- 9 January 2023
- journal article
- review article
- Published by Springer Science and Business Media LLC in Sports Medicine
- Vol. 53 (3), 595-613
- https://doi.org/10.1007/s40279-022-01805-w
Abstract
The physiological determinants of high-intensity exercise tolerance are important for both elite human performance and morbidity, mortality and disease in clinical settings. The asymptote of the hyperbolic relation between external power and time to task failure, critical power, represents the threshold intensity above which systemic and intramuscular metabolic homeostasis can no longer be maintained. After ~ 60 years of research into the phenomenon of critical power, a clear understanding of its physiological determinants has emerged. The purpose of the present review is to critically examine this contemporary evidence in order to explain the physiological underpinnings of critical power. Evidence demonstrating that alterations in convective and diffusive oxygen delivery can impact upon critical power is first addressed. Subsequently, evidence is considered that shows that rates of muscle oxygen utilisation, inferred via the kinetics of pulmonary oxygen consumption, can influence critical power. The data reveal a clear picture that alterations in the rates of flux along every step of the oxygen transport and utilisation pathways influence critical power. It is also clear that critical power is influenced by motor unit recruitment patterns. On this basis, it is proposed that convective and diffusive oxygen delivery act in concert with muscle oxygen utilisation rates to determine the intracellular metabolic milieu and state of fatigue within the myocytes. This interacts with exercising muscle mass and motor unit recruitment patterns to ultimately determine critical power.Keywords
This publication has 179 references indexed in Scilit:
- Pulmonary O2uptake kinetics as a determinant of high-intensity exercise tolerance in humansJournal of Applied Physiology, 2011
- Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humansJournal Of Physiology-London, 2011
- Dynamics of muscle microcirculatory and blood–myocyte O2 flux during contractionsActa Physiologica, 2010
- Critical speed in the rat: implications for hindlimb muscle blood flow distribution and fibre recruitmentJournal Of Physiology-London, 2010
- Endurance exercise performance: the physiology of championsJournal Of Physiology-London, 2008
- Muscle contraction-blood flow interactions during upright knee extension exercise in humansJournal of Applied Physiology, 2005
- Quantitative Evaluation of Oxygenation and Metabolism in the Human Skeletal MuscleOptical Review, 2003
- Oxygen Exchange Profile in Rat Muscles of Contrasting Fibre TypesJournal Of Physiology-London, 2003
- The Critical Power ConceptSports Medicine, 1993
- Metabolic and respiratory profile of the upper limit for prolonged exercise in manErgonomics, 1988