ObjectiveBeetroot juice is a source of dietary nitrate (NO3-) recognized as a potential ergogenic aid to enhance tolerance during endurance exercise of submaximal-to-maximal intensity. However, little is known about the effects of beetroot juice on exercise performance in intermittent sports such as tennis. The present study aimed to determine the effect of acute beetroot juice supplementation on movement patterns during a competitive tennis match in professional players.MethodsIn a double-blind and randomized experiment, nine professional tennis players performed two experimental trials 3 h after ingesting either 70 mL of a commercially-available concentrated beetroot juice (6.4 mmol NO3-) or placebo (0.005 mmol NO3-). In each experimental trial, players completed a 3-set tennis match and two performance tests (i.e., serve speed and isometric handgrip strength) before and after the match. Match-play running performance was recorded using wearable GPS and accelerometer units.ResultsIn comparison to the placebo trial, the acute beetroot juice supplementation did not modify any match-play running performance (p = 0.178 to 0.997, d = 0.01 to 0.42). Furthermore, beetroot juice supplementation did not alter the pre-to-post match change in serve speed (p = 0.663, ηp2 = 0.03) or isometric handgrip strength (p = 0.219, ηp2 = 0.18).Conclusions: The current results indicated that acute ingestion of a commercialized shot of nitrate-rich beetroot juice (70 mL containing 6.4 mmol of NO3-) did not produce any performance benefit on tennis matchplay. Thus, acute beetroot juice supplementation seems an ergogenic aid with little value to enhance physical performance in professional tennis players.
Keywords: Racquet sports; elite athlete; external load; nutrition; sports performance; supplement.