Short-term heat acclimation preserves knee extensor torque but does not improve 20 km self-paced cycling performance in the heat.

Content Provider	Europe PMC
Author	Osborne, John O. Stewart, Ian B. Borg, David N. Beagley, Kenneth W. Buhmann, Robert L. Minett, Geoffrey M.
Abstract	PurposeThis study investigated the effect of 5 days of heat acclimation training on neuromuscular function, intestinal damage, and 20 km cycling (20TT) performance in the heat.MethodsEight recreationally trained males completed two 5-day training blocks (cycling 60 min day−1 at 50% peak power output) in a counter-balanced, cross-over design, with a 20TT completed before and after each block. Training was conducted in hot (HA: 34.9 ± 0.7 °C, 53 ± 4% relative humidity) or temperate (CON: 22.2 ± 2.6 °C, 65 ± 8% relative humidity) environment. All 20TTs were completed in the heat (35.1 ± 0.5 °C, 51 ± 4% relative humidity). Neuromuscular assessment of knee extensors (5 × 5 s maximum voluntary contraction; MVC) was completed before and after each 20TT and on the first and last days of each training block.ResultsMVC torque was statistically higher after 5 days of HA training compared to CON (mean difference = 14 N m [95% confidence interval; 6, 23]; p < 0.001; d = 0.77). However, 20TT performance after 5 days of HA training was not statistically different to CON, with a between-conditions mean difference in the completion time of 68 s [95% confidence interval; − 9, 145] (p = 0.076; d = 0.35).ConclusionShort-term heat acclimation training may increase knee extensor strength without changes in central fatigue or intestinal damage. Nevertheless, it is insufficient to improve 20 km self-paced cycling performance in the heat compared to workload-matched training in a temperate environment. These data suggest that recreationally trained athletes gain no worthwhile performance advantage from short-term heat-training before competing in the heat.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00421-021-04744-y.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC8416835&blobtype=pdf
ISSN	14396319
Journal	European Journal of Applied Physiology [Eur J Appl Physiol]
Volume Number	121
DOI	10.1007/s00421-021-04744-y
PubMed Central reference number	PMC8416835
Issue Number	10
PubMed reference number	34148124
e-ISSN	14396327
Language	English
Publisher	Springer Berlin Heidelberg
Publisher Date	2021-06-19
Publisher Place	Berlin/Heidelberg
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2021
Subject Keyword	Athletic performance Muscle fatigue Thermotolerance Heat stress Hyperthermia
Content Type	Text
Resource Type	Article
Subject	Orthopedics and Sports Medicine Physiology (medical) Public Health, Environmental and Occupational Health Sports Science