Duration-dependant response of mixed-method pre-cooling for intermittent-sprint exercise in the heat


Autoria(s): Minett, Geoffrey M.; Duffield, Rob; Marino, Frank E.; Portus, Marc
Data(s)

2012

Resumo

This study examined the effects of pre-cooling duration on performance and neuromuscular function for self-paced intermittent-sprint shuttle running in the heat. Eight male, team-sport athletes completed two 35-min bouts of intermittent-sprint shuttle running separated by a 15-min recovery on three separate occasions (33°C, 34% relative humidity). Mixed-method pre-cooling was completed for 20 min (COOL20), 10-min (COOL10) or no cooling (CONT) and reapplied for 5-min mid-exercise. Performance was assessed via sprint times, percentage decline and shuttle-running distance covered. Maximal voluntary contractions (MVC), voluntary activation (VA) and evoked twitch properties were recorded pre- and post-intervention and mid- and post-exercise. Core temperature (T c), skin temperature, heart rate, capillary blood metabolites, sweat losses, perceptual exertion and thermal stress were monitored throughout. Venous blood draws pre- and post-exercise were analyzed for muscle damage and inflammation markers. Shuttle-running distances covered were increased 5.2 ± 3.3% following COOL20 (P < 0.05), with no differences observed between COOL10 and CONT (P > 0.05). COOL20 aided in the maintenance of mid- and post-exercise MVC (P < 0.05; d > 0.80), despite no conditional differences in VA (P > 0.05). Pre-exercise T c was reduced by 0.15 ± 0.13°C with COOL20 (P < 0.05; d > 1.10), and remained lower throughout both COOL20 and COOL10 compared to CONT (P < 0.05; d > 0.80). Pre-cooling reduced sweat losses by 0.4 ± 0.3 kg (P < 0.02; d > 1.15), with COOL20 0.2 ± 0.4 kg less than COOL10 (P = 0.19; d = 1.01). Increased pre-cooling duration lowered physiological demands during exercise heat stress and facilitated the maintenance of self-paced intermittent-sprint performance in the heat. Importantly, the dose-response interaction of pre-cooling and sustained neuromuscular responses may explain the improved exercise performance in hot conditions.

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/55356/

Publicador

Springer Verlag

Relação

http://eprints.qut.edu.au/55356/1/GM_EJAP_Precooling_Duration_Accepted.pdf

DOI:10.1007/s00421-012-2348-2

Minett, Geoffrey M., Duffield, Rob, Marino, Frank E., & Portus, Marc (2012) Duration-dependant response of mixed-method pre-cooling for intermittent-sprint exercise in the heat. European Journal of Applied Physiology, 112(10), pp. 3655-3666.

Direitos

Copyright 2012 Springer

The original publication is available at SpringerLink http://www.springerlink.com

Fonte

Faculty of Health; School of Exercise & Nutrition Sciences

Palavras-Chave #110000 MEDICAL AND HEALTH SCIENCES #precooling #thermoregulation #team-sports #heat stress #fatigue
Tipo

Journal Article