Novel Precooling Strategy Enhances Time Trial Cycling in the Heat

ROSS, MEGAN L. R.1,2; GARVICAN, LAURA A.1; JEACOCKE, NIKKI A.1; LAURSEN, PAUL B.2; ABBISS, CHRIS R.1,2,3; MARTIN, DAVID T.1; BURKE, LOUISE M.1

Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3181e93210
Applied Sciences
Abstract

Purpose: To develop and investigate the efficacy of a new precooling strategy combining external and internal techniques on the performance of a cycling time trial (TT) in a hot and humid environment.

Methods: Eleven well-trained male cyclists undertook three trials of a laboratory-based cycling TT simulating the course characteristics of the Beijing Olympic Games event in a controlled hot and humid environment (32°C-35°C at 50%-60% relative humidity). The trials, separated by 3-7 d, were undertaken in a randomized crossover design and consisted of the following: 1) CON-no treatment apart from the ad libitum consumption of cold water (4°C), 2) STD COOL-whole-body immersion in cold (10°C) water for 10 min followed by wearing a cooling jacket, or 3) NEW COOL-combination of consumption of 14 g of ice slurry ("slushie") per kilogram body mass made from a commercial sports drink while applying iced towels.

Results: There was an observable effect on rectal temperature (Trec) before the commencement of the TT after both precooling techniques (STD COOL < NEW COOL < CON, P < 0.05), but pacing of the TT resulted in similar Trec, HR, and RPE throughout the cycling protocol in all trials. NEW COOL was associated with a 3.0% increase in power (∼8 W) and a 1.3% improvement in performance time (∼1:06 min) compared with the CON trial, with the true likely effects ranging from a trivial to a large benefit. The effect of the STD COOL trial compared with the CON trial was "unclear."

Conclusions: This new precooling strategy represents a practical and effective technique that could be used by athletes in preparation for endurance events undertaken in hot and humid conditions.

Author Information

1Australian Institute of Sport, Belconnen, Australian Capital Territory, AUSTRALIA; 2School of Exercise Biomedical and Health Science, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA; and 3Division of Materials Science and Engineering, Commonwealth Scientific and Industrial Research Organisation, Belmont, Victoria, AUSTRALIA

Address for correspondence: Megan L. R. Ross, Physiology/Sports Nutrition, Australian Institute of Sport, PO Box 176, Belconnen, ACT 2616, Australia; E-mail: megan.ross@ausport.gov.au.

Submitted for publication February 2010.

Accepted for publication May 2010.

©2011The American College of Sports Medicine