Physiological mechanisms contributing to human exercise performance

Interest in the physiological factors that contribute to human exercise performance spans many decades of research. In this special issue of the Journal of Physiology, the Journal provides readers with two reviews related to the biological factors that contribute to human exercise performance. An overview of each review follows.

The first of these two outstanding review papers is authored by Dr Andy Jones from the University of Exeter, UK (Jones, 2024). This report provides a summary of Dr Jones’ keynote lecture presented at the Integrative Physiology of Exercise meeting in Baltimore, MD (USA) in 2022. In this interesting and well-crafted review, Dr Jones emphasizes that endurance exercise performance is associated with three key physiological factors: (1) maximal oxygen uptake (VO₂ max); (2) economy or efficiency during exercise; and (3) the fraction of VO₂ max that can be maintained during prolonged exercise. Professor Jones emphasizes that during prolonged endurance exercise, these variables are not static and are subject to deterioration as exercise proceeds. In particular, the fraction of VO₂ max that can be maintained during fatiguing endurance exercise often decreases by 10% or more as the exercise bout proceeds. Therefore, Jones argues that ‘resilience’ (defined as the ability to resist fatigue during endurance exercise) should be considered as a fourth physiological factor that determines human endurance performance. The report debates the possible physiological mechanisms that contribute to physiological resilience and identifies several important topics for future research. Clearly, this outstanding report is a must read for physiologists interested in the physiological mechanisms that contribute to endurance exercise performance.

The second report in this special issue addresses the important topic of ‘sex differences in human performance’. Drs Sandra Hunter and Jonathon Senefeld coauthored this thought-provoking review (Hunter & Senefeld, 2024) and, like the Jones review, this paper highlights Dr Hunters’ keynote lecture presented at the Integrative Physiology of Exercise meeting held in Baltimore, MD in 2022. This well-written review carefully chronicles our current understanding of the physiological mechanisms responsible for the sex differences in human physical performance. The report concludes that males outperform females in many exercise events because they are faster, stronger and more powerful. The review highlights the key physiological differences that contribute to these sex differences in human performance and the physiological mechanisms responsible for these differences. Specifically, the role that sex-steroid hormones, sex hormones and epigenetics play in sex differences in physical performance is discussed. Importantly, this review also provides a scientific rationale for policy decisions on sex-based categories in sports participation during both puberty and adulthood. For physiologists interested in human exercise performance, this review is required reading.