Acute beetroot juice supplementation did not enhance intermittent running performance in trained rugby players.

PURPOSE: Since the effect of dietary nitrate (NO3 - ) supplementation on rugby performance is unclear, the aim of the present study was to determine the effect of acute NO3 - supplementation, on the modified Yo-Yo intermittent recovery level 1 (IR1) performance test in trained male rugby players. Methods: In a randomised, counterbalanced, double-blind, placebo-controlled crossover design, 12 trained rugby union players performed two experimental trials three hours after supplementation of either 140 mL NO3 - -rich (BRJ; ∼12.8 mmol NO3 - ) or NO3 - -depleted (PLA) BRJ. After blood sampling, players performed the modified Yo-Yo IR1 test. Countermovement jumps (CMJ) were also measured before (pre-CMJ) and after (post-CMJ) the prone Yo-Yo IR1 test. Results: Plasma NO3 - (BRJ: 570 ± 146 µM vs. PLA: 72 ± 23 µM) and nitrite (NO2 - ) concentrations (BRJ: 320 ± 123 nM vs. PLA: 103 ± 57 nM) were increased after BRJ compared to PLA supplementation (both P < 0.001). Performance in the modified Yo-Yo IR1 test did not differ between BRJ (542 ± 209 m) and PLA (498 ± 185 m, P = 0.3). The jump height in pre-CMJ and in post-CMJ were similar between trials (both P > 0.05). Conclusions: Acute BRJ supplementation increased plasma NO3 - and NO2 - concentrations but had no benefit on an intermittent running test that reflects the demands of rugby performance, and CMJ performances. The findings do not support acute high-dose NO3 - supplementation as an ergogenic aid to enhance physical performance in trained male rugby players.

HIGHLIGHTS: It has been suggested that NO3 - supplementation might have ergogenic potential for team sport athletes, however, the impact of nitrate supplementation on intermittent running performance of rugby players is unclear. Therefore, we aimed to assess the impact of acute NO3 - supplementation on the Prone Yo-Yo IR1 performance in trained male rugby players.Acute supplementation of high-dose nitrate supplementation substantially increased plasma NO3 - and NO2 - concentrations but did not improve the Prone Yo-Yo IR1 performance and countermovement jump performance in trained rugby players.The findings of the present study do not support acute BRJ supplementation as a nutritional ergogenic aid for trained rugby players, at least for the Prone Yo-Yo IR1performance, but are in line with the notion that supplementation of NO3 - is less likely to be ergogenic in well trained athletes.