Yuiko Matsuura

Purpose : Open-water swimmers need to train with wetsuits to get familiar with them; however, body core temperature ( T core ) kinetics when using wetsuits in swimming-pool training remains unclear. The present study assessed the effects of wetsuit use in pool training on T core , subjective perceptions, and swimming performance to obtain suggestions for wearing wetsuits in training situations. Methods : Four elite/international-level Japanese swimmers (2 female, age 24 [1] y) completed two 10-km trials with (WS) and without wetsuit (SS) in the swimming pool ( T w : 29.0 °C). During the trial, swimmers were allowed to remove their wetsuit if they could no longer tolerate the heat. T core was continuously recorded via ingestible temperature sensors. Swimming speed was estimated from every 100-m lap time. Results : T core increased by distance in both trials in all swimmers. T core when swimmers removed their wetsuit in the WS (distance: 3800 [245] m, time: 2744 [247] s) was higher than that at the same distance in the SS in all swimmers. Rating of perceived exertion was higher in the SS than the WS, and swimming speed was slower in the WS than the SS in all swimmers. Conclusion : Wetsuit use during pool training increases T core and decreases swimming performance. Although wearing wetsuits in training situations is important for familiarization, for the safety of the swimmers, it is recommended that they remove their wetsuit if they feel too hot.