Hand and forearm immersion in hot water at half-time enhances subsequent leg muscle strength.

We aimed to investigate the effects of hot-water immersion of the hand and forearm during half-time (HT) on the physiological responses, leg muscle strength, and cycling sprint performance in the cold. Ten recreationally active men performed the experimental trials that consisted of 40 min intermittent cycling, followed by a 15-min HT, and then an intermittent cycling sprint test in a cold (5°C and 50% relative humidity). During HT, the participants underwent two different interventions: seated rest (CON) or hand and forearm heating (HEAT). The intermittent cycling sprint test comprised 10 sets of 5 s of maximal pedaling and 25 s of recovery. In addition, the participants performed maximal voluntary contraction (MVC) in knee extension before and after HT. Although the peak power output in the intermittent cycling sprint test did not significantly differ between trials (p>0.05), the rectal temperature (T re ) following HT in HEAT was significantly higher than in CON (p=0.026). In addition, the MVC force after HT was significantly higher in HEAT than in CON (p<0.001). This suggests hot-water immersion of hand and forearm during HT improves knee extensor muscle strength and attenuates the T re decrease in a cold environment.