Research Repository

Hot conditions improve power output during repeated cycling sprints without modifying neuromuscular fatigue characteristics

Girard, Olivier, Bishop, David and Racinais, S (2012) Hot conditions improve power output during repeated cycling sprints without modifying neuromuscular fatigue characteristics. European Journal of Applied Physiology, 113 (2). pp. 359-369. ISSN 1439-6319 (print) 1439-6327 (online)

Full text for this resource is not available from the Research Repository.

Abstract

This study investigated the effect of hot conditions on repeated sprint cycling performance and post-exercise alterations in isometric knee extension function. Twelve physically active participants performed 10 × 6-s “all-out” sprints on a cycle ergometer (recovery = 30 s), followed 6 min later by 5 × 6-s sprints (recovery = 30 s) in either a neutral (24 °C/30 %rH) or a hot (35 °C/40 %rH) environment. Neuromuscular tests including voluntary and electrically evoked isometric contractions of the knee extensors were performed before and after exercise. Average core temperature during exercise was higher (38.0 ± 0.1 vs. 37.7 ± 0.1 °C, respectively; P < 0.05) in hot versus neutral environments. Peak power output decreased (−17.9 % from sprint 1 to sprint 10 and −17.0 % from sprint 11 to sprint 15; P < 0.001) across repetitions. Average peak power output during the first ten sprints was higher (+3.1 %; P < 0.01) in the hot ambient temperature condition. Maximal strength (−12 %) and rate of force development (−15 to −26 %, 30–200 ms from the onset of contraction) decreased (P < 0.001) during brief contractions after exercise, irrespectively of the ambient temperature. During brief maximal contractions, changes in voluntary activation (~80 %) were not affected by exercise or temperature. Voluntary activation declined (P < 0.01) during the sustained contraction, with these reductions being more pronounced (P < 0.05) after exercise but not affected by the ambient temperature. Resting twitch amplitude declined (P < 0.001) by ~42 %, independently of the ambient temperature. In conclusion, heat exposure has no effect on the pattern and the extent of isometric knee extensor fatigue following repeated cycling sprints in the absence of hyperthermia.

Item Type: Article
Uncontrolled Keywords: repeated-sprint ability, temperature, neuromuscular fatigue, knee extensors, motor nerve stimulations
Subjects: FOR Classification > 1106 Human Movement and Sports Science
Faculty/School/Research Centre/Department > School of Sport and Exercise Science
Faculty/School/Research Centre/Department > Institute of Sport, Exercise and Active Living (ISEAL)
Depositing User: VUIR
Date Deposited: 13 Jan 2014 02:27
Last Modified: 26 Feb 2014 03:24
URI: http://vuir.vu.edu.au/id/eprint/24236
DOI: https://doi.org/10.1007/s00421-012-2444-3
ePrint Statistics: View download statistics for this item
Citations in Scopus: 31 - View on Scopus

Repository staff only

View Item View Item

Search Google Scholar