Effects of Different Precoolings on Incremental Cycling Exercise Performance of University Cyclists under Hot and Humid Conditions = Effects of Different Precoolings on Incremental Cycling Exercise Performance of University Cyclists under Hot and Humid Conditions

다국어 초록 (Multilingual Abstract)

Purpose: Many sports are carried out under high temperature and high humidity environment, so conventional warm-up is adverse for the endurance exercise in this case. Instead, precooling may be another "warm-up" activities that is help endurance athletes resist high temperatur, and delaying fatigue. this research comparatively study the effects of different pre-cooling methods on incremental cycling exercise performance in hot and humid conditions, and explore proper precooling strategy being suitable for high temperature and high humidity environment. Method: This experiment is designed by a randomized crossover self-control. Twenty participants recruited from University Riding Club are male cyclists, Each subject must perform three trials, control (CON), low body immersion precooling (LBI) and whole body immersion precooling (WBI). After 20min precooling intervention, subjects immediately proceed to incremental cycling exercising to be exhausted in a environment simulation laboratory at high temperature (35-38℃) and high humidity (60%-70%) environment, Related physiological indexes and performance of motion data are acquired. Result: Compared with CON, exercise time, distance and workload in LBI respectively increased by average of 3.43 minutes, 1.13 km, and 42.89kj (P < 0.01), while it is 2.62 minutes, 0.95 km and 33.89kj in WBI (P < 0.05). Obviously, LBI are significantly different from WBI (P < 0.05); The LBI and WBI significantly decreased the subjects, HR, respectively by 7.3±4.0 and 7.0±3.3（P＜0.05）; There are significant correlations between exercise performance in high temperature and high humidity environment and baseline HR、reserve heart rate and heat storage（ P<0.01，r>0.7） Conclusion: Precooling significantly improves athletics capacity of exercise in high temperature and high humidity environment, presented prolonging exercise time, distance and increasing workload, and the effects of LBI is more obvious; Local precooling and systemic precooling can significantly reduce the base HR and core temperature, and increase the reservation of heart rate and heat storage, and the local precooling is more effective; Comprehensive analysis shows that local precooling and systemic precooling can significantly improve the exercise perforemance in high temperature and high humidity environment. More over, the local precooling is more effective.