Effect of precooling on high intensity cycling performance

Objective-To examine the effects of precooling skin and core temperature on a 70 second cycling power test performed in a warm and humid environment ( 29 degrees C, 80% relative humidity). Methods-Thirteen male national and international level representative cycli sts (mean (SD) age 24.1 (4.1) years; height 181.5 (6.2) cm; weight 75.5 (6. 4) kg; maximal oxygen uptake ((V) over doto(2peak)) 66.1 (7.0) ml/kg/min) w ere tested in random order after either 30 minutes of precooling using cold water immersion or under control conditions (no precooling). Tests were se parated by a minimum of two days. The protocol consisted of a 10 minute war m up at 60% of (V) over doto(2peak) followed by three minutes of stretching . This was immediately followed by the 70 second power test which was perfo rmed on a standard road bicycle equipped with 172.5 mm powermeter cranks an d mounted on a stationary ergometer. Results-Mean power output for the 70 second performance test after precooli ng was significantly (p < 0.005) increased by 3.3 (2.7)% from 581 (57) W to 603 (60) W. Precooling also significantly (p < 0.05) decreased core, mean body, and upper and lower body skin temperature; however, by the start of t he performance test, lower body skin temperature was no different from cont rol. After precooling, heart rate was also significantly lower than control throughout the warm up (p < 0.05). Ratings of perceived exertion were sign ificantly higher than the control condition at the start of the warm up aft er precooling, but lower than the control condition by the end of the warm up (p < 0.05). No differences in blood lactate concentration were detected between conditions. Conclusions-Precooling improves short term cycling performance, possibly by initiating skin vasoconstriction which may increase blood availability to the working muscles. Future research is required to determine the physiolog ical basis for the ergogenic effects of precooling on high intensity exerci se.