Countermovement Jump, Handgrip, and Balance Performance Change During Euhydration, Mild-Dehydration, Rehydration, and Ad Libitum Drinking.

Objective: To examine the effects of euhydration, mild-dehydration, rehydration, and ad libitum drinking on countermovement jump (CMJ), handgrip strength, and performance of balance error scoring system test (BESS).Methods: Eighteen healthy male subjects (mean[M]+/- standard deviation[SD]; age, 23 +/- 3y; body mass, 80.1 +/- 9.7 kg; height, 175.8 +/- 5.7 cm) participated in this study. Participants reported to the laboratory to perform CMJ, handgrip strength, and BESS with different hydration statuses (euhydrated, EUH; when they initially sensed thirst, THIRST; dehydrated, DEH; following 30 minutes of rehydration, REH; and following 24-h ad libitum drinking, AD). Results: CMJ at EUH (M +/- SD; 54.6 +/- 3.0 cm) was significantly higher than DEH (52.8 +/- 3.0 cm, p = 0.027) and REH (52.6 +/- 2.8 cm, p < 0.001). However, there was no difference between DEH and REH (p = 0.643). CMJ at THIRST (54.9 +/- 3.0 cm, p = 0.004) was higher than REH. Also, AD (53.8 +/- 2.8 cm, p = 0.027) was higher than REH. In left handgrip strength, THIRST (48.6 +/- 9.5 kg) was higher than EUH (46.7 +/- 10.1 kg, p = 0.018), DEH (45.8 +/- 10.0 kg, p = 0.013), REH (46.1 +/- 9.5 kg, p = 0.004), and AD (47.1 +/- 9.7 kg, p = 0.05). Additionally, in the single-leg stance on a foam pad, more BESS errors were found at THIRST (6 +/- 2) compared to EUH (5 +/- 2, p = 0.007) and AD (5 +/- 2, p = 0.002). Conclusion: The findings of this study were:-2% of mild dehydration induced by 24-h fluid restriction decreased lower body power measured by CMJ, acute rehydration did not restore the loss of lower body power induced by dehydration, and-0.5-0.9% of dehydration did not decrease lower body power.(c) 2022 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).