The aim of this study was to determine whether pre-cooling procedures improve both maximal sprint and sub-maximal work during
intermittent-sprint exercise. Nine male rugby players performed a familiarisation session and three testing sessions of a
2 × 30-min intermittent sprint protocol, which consisted of a 15-m sprint every min separated by free-paced hard-running,
jogging and walking in 32°C and 30% humidity. The three sessions included a control condition, Ice-vest condition and Ice-bath/Ice-vest
condition, with respective cooling interventions imposed for 15-min pre-exercise and 10-min at half-time. Performance measures
of sprint time and % decline and distance covered during sub-maximal exercise were recorded, while physiological measures
of core temperature (
T
core), mean skin temperature (
T
skin), heart rate, heat storage, nude mass, rate of perceived exertion, rate of thermal comfort and capillary blood measures of
lactate [La
−], pH, Sodium (Na
+) and Potassium (K
+) were recorded. Results for exercise performance indicated no significant differences between conditions for the time or
% decline in 15-m sprint efforts or the distance covered during sub-maximal work bouts; however, large effect size data indicated
a greater distance covered during hard running following Ice-bath cooling. Further, lowered
T
core,
T
skin, heart rate, sweat loss and thermal comfort following Ice-bath cooling than Ice-vest or Control conditions were present,
with no differences present in capillary blood measures of [La
−], pH, K
+ or Na
+. As such, the ergogenic benefits of effective pre-cooling procedures in warm conditions for team-sports may be predominantly
evident during sub-maximal bouts of exercise.
Keywords Central fatigue - Heat-strain - Ice-bath - Repeat-sprint - Thermoregulation