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Sex differences in fatigability following exercise normalised to the power-duration relationship

journal contribution
posted on 22.09.2020 by Paul Ansdell, Jakob Skarabot, Elliott Atkinson, Sarah Corden, Amber Tygart, Kirsty Hicks, Kevin Thomas, Sandra Hunter, Glyn Howatson, Stuart Goodall
Due to morphological differences, females demonstrate greater fatigue resistance of locomotor muscle during single‐limb and whole‐body exercise modalities. Whilst females sustain a greater relative intensity of single‐limb, isometric exercise than males, limited investigation has been performed during whole‐body exercise. Accordingly, this study established the power‐duration relationship during cycling in 18 trained participants (8 females). Subsequently, constant‐load exercise was performed at critical power (CP)‐matched intensities within the heavy and severe domains, with the mechanisms of fatigability assessed via non‐invasive neurostimulation, near‐infrared spectroscopy, and pulmonary gas exchange during and following exercise. Relative CP (72±5 vs. 74±2% Pmax, p = 0.210) and curvature constant (51±11 vs. 52±10 J·Pmax−1, p = 0.733) of the power‐duration relationship were similar between males and females. Subsequent heavy (p = 0.758) and severe intensity (p = 0.645) exercise time to task failures were not different between sexes. However, females experienced lesser reductions in contractile function at task failure (p≤0.020), and greater vastus lateralis oxygenation (p≤0.039) during both trials. Reductions in voluntary activation occurred following both trials (p<0.001), but were less in females following the heavy trial (p = 0.036). Furthermore, during the heavy‐intensity trial only, corticospinal excitability was reduced at the cortical (p = 0.020) and spinal (p = 0.036) levels, but these reductions were not sex‐dependent. Other than a lower respiratory exchange ratio in the heavy trial for females (p = 0.039), no gas exchange variables differed between sexes (p≥0.052). Collectively, these data demonstrate that whilst the relative power‐duration relationship is not different between males and females, the mechanisms of fatigability during CP‐matched exercise above and below critical power are mediated by sex.

History

School

  • Sport, Exercise and Health Sciences

Published in

The Journal of Physiology

Publisher

Wiley

Version

AM (Accepted Manuscript)

Rights holder

© The Authors. The Journal of Physiology © The Physiological Society

Publisher statement

This is the peer reviewed version of the following article: Ansdell, P., Škarabot, J., Atkinson, E., Corden, S., Tygart, A., Hicks, K.M., Thomas, K., Hunter, S.K., Howatson, G. and Goodall, S. (2020), Sex differences in fatigability following exercise normalised to the power‐duration relationship. Journal of Physiology, doi:10.1113/JP280031, which has been published in final form at https://doi.org/10.1113/JP280031. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Acceptance date

07/09/2020

Publication date

2020-09-26

Copyright date

2020

ISSN

0022-3751

eISSN

1469-7793

Language

en

Depositor

Dr Jakob Skarabot. Deposit date: 21 September 2020

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