SHORT-TERM DIET MODIFICATION CAN MODERATE THE LEVELS OF FATIGUE INDICES IN TENNIS PLAYERS

Abstract

Aim. The Objective of this study was to investigate the effect of short-term diet modification on plasma levels of fatigue indices (including serotonin, dopamine, serotonin/dopamine ratio, ammonia, and lactate) following a two-hour tennis match. Materials and methods. 32 semi-professional male tennis players participated in a randomized cross-over design in the form of short-term diet modification (DM) and non-modification (N-DM) interventions. They played
a formal two-hour match and plasma levels of fatigue indices and RPE scores of participants were determined before and after each tennis match. Results. The results of this study showed that after the match, the serotonin, dopamine, lactate, and ammonia increased significantly compared to pre-match in both interventions (p < 0.001) and that the increase in serotonin/dopamine ratio was only significant in N-DM (p < 0.001). However, the increase in ammonia (p < 0.001) and serotonin (p < 0.05) as well as the serotonin/dopamine ratio (p < 0.05) in DM was significantly lower than in N-DM. Although the change in lactate and dopamine levels was respectively 21% and 8% higher than in N-DM after the match, these changes were not significant. A large and moderate correlation was found between RPE and serotonin/dopamine ratio (p < 0.001) and other variables (p < 0.001) respectively, which was negative for dopamine (p < 0.05). Conclusion. In this study, it was shown that short-term diet modification, could modulate the majority of fatigue indices. Therefore, diet modification can be recommended to alleviate fatigue and maintain performance among tennis players. It was also shown that the serotonin/dopamine ratio can be the most reliable among fatigue indices.