title: Neck-cooling improves repeated sprint performance in the heat.
abstract: The present study evaluated the effect of neck-cooling during exercise on repeated sprint ability in a hot environment. Seven team-sport playing males completed two experimental trials involving repeated sprint exercise (5 × 6 s) before and after two 45 min bouts of a football specific intermittent treadmill protocol in the heat (33.0 ± 0.2°C; 53 ± 2% relative humidity). Participants wore a neck-cooling collar in one of the trials (CC). Mean power output and peak power output declined over time in both trials but were higher in CC (540 ± 99 v 507 ± 122 W, d = 0.32; 719 ± 158 v 680 ± 182 W, d = 0.24 respectively). The improved power output was particularly pronounced (d = 0.51-0.88) after the 2nd 45 min bout but the CC had no effect on % fatigue. The collar lowered neck temperature and the thermal sensation of the neck (P < 0.001) but had no effect on heart rate, fluid loss, fluid consumption, lactate, glucose, plasma volume change, cortisol, or thermal sensation (P > 0.05). There were no trial differences but interaction effects were demonstrated for prolactin concentration and rating of perceived exertion (RPE). Prolactin concentration was initially higher in the collar cold trial and then was lower from 45 min onwards (interaction trial × time P = 0.04). RPE was lower during the football intermittent treadmill protocol in the collar cold trial (interaction trial × time P = 0.01). Neck-cooling during exercise improves repeated sprint performance in a hot environment without altering physiological or neuroendocrinological responses. RPE is reduced and may partially explain the performance improvement.
authors.affiliation: Department of Sports Science, School of Science and Technology, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University Nottingham, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sunderland
authors.affiliation: Department of Sports Science, School of Science and Technology, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University Nottingham, UK.
authors.forename: Ryan
authors.initials: R
authors.lastname: Stevens
authors.affiliation: Department of Sports Science, School of Science and Technology, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University Nottingham, UK.
authors.forename: Bethan
authors.initials: B
authors.lastname: Everson
authors.affiliation: Department of Life Sciences, University of Roehampton London, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Tyler
keywords: high-intensity; hyperthermia; pacing; team-sport; thermoregulation; treadmill