Hydration Status of Junior Tennis Players and the Difference after a Lecture on Its Practice.

Dehydration reduces exercise performance and causes heat-related illness. However, the fact that dehydration is a serious sports injury is often forgotten, especially among junior tennis players, who engage in tennis matches alone without receiving advice from others. Our objective was to investigate the hydration status of junior tennis players and the difference after attending a lecture on the importance of hydration. In total, 157 junior tennis players attending a training camp participated in this study. The duration of the camp was two days, and a lecture was organized on the first night to educate the players about hydration using a body mass scale. Body mass (BM) was measured immediately before and after practice on the first and second day. The water loss rate (WLR) was calculated by dividing the loss in BM during practice by the BM before practice. In total, 34.4% of players had attended a lecture on hydration in the past. These players had a lower WLR than those who had not, but the difference was not significant. The WLR was significantly lower after attending our lecture than that before. This study suggests that a lecture on hydration could immediately improve the hydration status of the junior tennis players; however, this effect may not be lasting. They may need help from their coaches and parents to implement what they have learned in lecture.