Durability refers to an athlete’s ability to maintain their physiological capacity and performance levels over extended periods of physical exertion and resist the negative effects of fatigue. In other words, it means how well an athlete can sustain power, pace, etc., in prolonged, submaximal exercise (e.g., an ultra-trail race, a multi-day event). Durability can be seen as a form of fatigue resistance and is a relatively new area of focus in exercise science. There is a slight distinction between “fatigue resistance” and “durability”; the former generally refers to neuromuscular fatigue during short, maximal exercise bouts, while the latter applies to longer, submaximal exercise.
References
Matomäki, P., Heinonen, O. J., Nummela, A., Laukkanen, J., Auvinen, E. P., Pirkola, L., & Kyröläinen, H. (2023). Durability is improved by both low and high intensity endurance training. Frontiers in physiology, 14, 1128111. https://doi.org/10.3389/fphys.2023.1128111
Maunder, E., Seiler, S., Mildenhall, M. J., Kilding, A. E., & Plews, D. J. (2021). The Importance of ‘Durability’ in the Physiological Profiling of Endurance Athletes. Sports medicine (Auckland, N.Z.), 51(8), 1619–1628. https://doi.org/10.1007/s40279-021-01459-0