The purpose of this study was to examine the influence of the swim cap on thermal responses during swimming. Ten male competitive swimmers (age 20.0±1.3yr, body weight 66.2±6.3kg, %Fat 18.4±3.2%) performed sub-maximal 20-minutes swimming in a 25m indoor pool (room; 28.7±1.4℃, water; 28.8±0.4℃, 67.5±6.4%rh) using front crawl stroke; they wore either of two types of swim caps - the waterproof silicone cap (SC) or the non-waterproof mesh cap (MC). Forehead skin temperature (Tfh), occipital temperature (Toc) and heart rate (HR) were measured throughout the swimming. Tympanic (Tty) and oral (Toral) temperature were measured prior to and after each swim. Rating of perceived exertion (RPE), and perceived thermal sensation on the head (TSH) and body (TSB) were measured on completion of the trial. Regarding the changes in Tfh and Toc during the trial, they both declined during the first five minutes and then, except for Toc in MC, assumed an upward curve; Toc in MC didn't rise, but kept stable from after the first five minutes to the last. Measurement after the trial showed significant differences in Tfh (SC: 33.70±0.82℃, MC: 32.45±0.69℃) and Toc (SC: 30.85±1.18 ℃, MC: 28.95±0.55 ℃). On the other hand, there were no significant differences both in Toral and Tty between SC and MC after the trial. However, MC depressed Tty significantly both before and after the trial (-0.32±0.28℃, p<0.05). No significant difference was observed in TSB between SC and MC, but TSH was higher for SC than for MC (SC: 6.7±0.8, MC: 5.6±0.8, p<0.05). These results were evidently brought about by the difference of the swim caps; the waterproof swim cap acts as thermal barriers to the heat produced in the cephalicus. Therefore, in case of prolonged training and competition, it is desirable for swimmers to select their swim caps with water temperature environment in mind in order to avoid cranialis temperature elevation.

DESCENTE SPORTS SCIENCE Vol.24/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE