Novel precooling strategy enhances time trial cycling in the heat.
OBJECTIVE
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 (T(rec)) 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 T(rec), HR, and RPE throughout the cycling protocol in all trials. NEW COOL was associated with a 3.0% increase in power (approximately 8 W) and a 1.3% improvement in performance time (approximately 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.
Australian Institute of Sport, Belconnen, Australian Capital Territory, Australia.
Megan L R
ML
Ross
Laura A
LA
Garvican
Nikki A
NA
Jeacocke
Paul B
PB
Laursen
Chris R
CR
Abbiss
David T
DT
Martin
Louise M
LM
Burke
D000293:Adolescent; D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D001831:Body Temperature; D001833:Body Temperature Regulation; D003080:Cold Temperature; D018592:Cross-Over Studies; D004326:Drinking / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007053:Ice; D008297:Male; D013995:Time; D055815:Young Adult
D007053:Ice