Castle Paul C, Macdonald Adam L, Philp Andrew, Webborn Anthony, Watt Peter W, Maxwell Neil S
Chelsea School Research Centre, University of Brighton, 30 Carlisle Rd., Eastbourne BN20 7SP, UK.
J Appl Physiol (1985). 2006 Apr;100(4):1377-84. doi: 10.1152/japplphysiol.00822.2005. Epub 2005 Dec 8.
We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P < 0.01), but it was similar to Vest. Packs and Water blunted the rise of Tmu until minute 16 and for the duration of the CISP (40 min), respectively (P < 0.01). Reductions in PPO occurred from minute 32 onward in Control, and an increase in PPO by approximately 4% due to Packs was observed (main effect; P < 0.05). The method of precooling determined the extent to which heat strain was reduced during intermittent sprint cycling, with leg precooling offering the greater ergogenic effect on PPO than either upper body or whole body cooling.
在炎热潮湿的环境中进行运动时，热应激会得到缓解，肌肉温度（Tmu）会降低，从而峰值功率输出（PPO）的下降会延迟。12名男性团队运动运动员完成了四项自行车间歇冲刺方案（CISP）。每个CISP包括20个2分钟的时段，每个时段包括10秒的被动休息、5秒对抗7.5%体重阻力的最大冲刺以及105秒的主动恢复。在炎热潮湿的环境中（平均±标准误；33.7±0.3摄氏度，相对湿度51.6±2.2%），以随机顺序进行CISP，之前分别有20分钟不进行冷却（对照）、通过冰背心预冷（背心）、冷水浸泡（水）以及用冰袋覆盖大腿（冰袋）。在CISP期间，对照组的热应激增加速率比水组和冰袋组更快（P<0.01），但与背心组相似。冰袋组和水组分别在第16分钟之前和CISP持续期间（40分钟）抑制了Tmu的升高（P<0.01）。在对照中，从第32分钟起PPO出现下降，而观察到冰袋组使PPO增加了约4%（主效应；P<0.05）。预冷方法决定了间歇冲刺骑行期间热应激降低的程度，腿部预冷对PPO的促力效应比上半身或全身冷却更大。
