The Ergogenic Effects of Intermittent Palm Cooling on Repeated Baseball Throwing Are Reversed when Cooling-Induced Pain Occurs

Intermittent palm cooling (PC) could benefit strength performance. However, its effect on baseball throwing, which requires explosive strength, has yet to be determined. This study aimed to examine whether intermittent PC would enhance repeated baseball throwing performance and how pain after PC would affect outcomes. Twenty-two university division II male baseball athletes were instructed to perform five sets of 10 throws at maximum speed toward a target, separated by 3-min of recovery with PC into 10°C water or non-cooling (NC). Participants were classified into the no-pain group (NPG, n = 10) and mild-to-moderate pain group (PG, n = 12) according to their pain sensation after PC for data analysis. The results showed a significantly lower rating of perceived exertion under PC conditions (p < 0.05). In the NPG, PC resulted in higher mean throw velocity (107.9 ± 9.9 vs. 106.9 ± 10.2 km/h), maximal throw velocity (112.5 ± 9.0 vs. 111.2 ± 9.8 km/h), accuracy, and the arousal level than NC; in the PG, PC resulted in lower mean throw velocity (101.0 ± 11.1 vs. 105.2 ± 10.5 km/h) and maximal throw velocity (105.0 ± 10.8 vs. 108.7 ± 9.8 km/h) when compared with NC (p < 0.05). However, no significant difference was noted in accuracy and arousal levels between PC and NC (p > 0.05) in the PG. In conclusion, after PC, pain-free baseball athletes can enhance their baseball throwing performance. The presence or absence of pain after PC can serve as an initial assessment of whether to use it as an ergogenic aid strategy.