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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: January 2011 - Volume 43 - Issue 1 - pp 123-133
doi: 10.1249/MSS.0b013e3181e93210
Applied Sciences

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.

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