AUTHOR=Périard Julien D. , Pyne David B. , Bishop David J. , Wallett Alice , Girard Olivier 

TITLE=Short-Term Repeated-Sprint Training in Hot and Cool Conditions Similarly Benefits Performance in Team-Sport Athletes

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.01023

DOI=10.3389/fphys.2020.01023

ISSN=1664-042X

ABSTRACT=<p>This study compared the performance and physiological adaptations of short-term repeated-sprint training in HOT [40°C and 40% relative humidity (RH)] and COOL (20°C and 40% RH) conditions in team-sport athletes. Twenty-five trained males completed five training sessions of 60 min over 7 days in HOT (<italic>n</italic> = 13) or COOL (<italic>n</italic> = 12) conditions, consisting of a submaximal warm-up and four sets of maximal sprints. Before and after the intervention, intermittent shuttle running performance was assessed in cool and repeated-sprint ability in hot conditions; the latter preceded and followed by neuromuscular function testing. During the repeated-sprint training sessions, skin (~8.4°C) and core (~0.17°C) temperatures were higher in HOT than COOL (<italic>p</italic> &lt; 0.05) conditions. Shuttle running distance increased after both interventions (<italic>p</italic> &lt; 0.001), with a non-significant (<italic>p</italic> = 0.131) but larger effect in HOT (315 m, <italic>d</italic> = 1.18) than COOL (207 m, <italic>d</italic> = 0.51) conditions. Mean (~7%, <italic>p</italic> &lt; 0.001) and peak (~5%, <italic>p</italic> &lt; 0.05) power during repeated-sprinting increased following both interventions, whereas peak twitch force before the repeated-sprint assessment was ~10% lower after the interventions (<italic>p</italic> = 0.001). Heart rate during the repeated-sprint warm-up was reduced (~6 beats.min<sup>−1</sup>) following both interventions (<italic>p</italic> &lt; 0.01). Rectal temperature was ~0.14°C lower throughout the repeated-sprint assessment after the interventions (<italic>p</italic> &lt; 0.001), with larger effects in HOT than COOL during the warm-up (<italic>p</italic> = 0.082; <italic>d</italic> = −0.53 vs. <italic>d</italic> = −0.15) and repeated-sprints (<italic>p</italic> = 0.081; <italic>d</italic> = −0.54 vs. <italic>d</italic> = −0.02). Skin temperature (<italic>p</italic> = 0.004, <italic>d</italic> = −1.11) and thermal sensation (<italic>p</italic> = 0.015, <italic>d</italic> = −0.93) were lower during the repeated-sprints after training in HOT than COOL. Sweat rate increased (0.2 L.h<sup>−1</sup>) only after training in HOT (<italic>p</italic> = 0.027; <italic>d</italic> = 0.72). The intensive nature of brief repeated-sprint training induces similar improvements in repeated-sprint cycling ability in hot conditions and intermittent running performance in cool conditions, along with analogous physiological adaptations, irrespective of the environmental conditions in which training is undertaken.</p>