biostudies-literatureUnknown13Moreno B<b>Background:</b> Beetroot juice is a sport supplement with a high level of evidence on the physical performance enhancement. However, in swimming, there is no clear data about the effects of beetroot juice on performance. <b>Objective:</b> To investigate whether an acute intake of beetroot juice (BJ) improves the performance of competitive swimmers in a repeated maximum swimming effort. <b>Method:</b> Thirteen national-level swimmers (six females and seven males), participated in this randomized, double-blind crossover study. In two different trials, swimmers ingested a 70-mL placebo shot (.04 mmol NO₃ ^-; PLA) or a 70-mL Beet-It shot (6.4 mmol of NO₃ ^-beet juice [BJ]) 3 h before undergoing a 6 × 100-m front-crawl maximal effort test with 7 min rest between each 100 m. <b>Results:</b> Overall, 100-m times showed no difference between the BJ and PLA groups (<i>p</i> = .364), although a possibly shorter time was observed for BJ in the last repetition (<i>p</i> = .104; mean difference [MD] = -.99 s, mean-based inference [MBI] = 49/51/0). Participants in the BJ condition showed a possibly lower rate of perceived exertion in the first (<i>p</i> = .242, MD = -.85, MBI = 70/28/2) and second repetitions (<i>p</i> = .165, MD = 1.15, MBI = 83/16/1), whereas Total Quality Recovery scale scores were likely higher in the first (<i>p</i> = .110, MD = 1.15, MBI = 83/16/1) and third (<i>p</i> = .082, MD = -.77, MBI = 70/29/1) repetitions compared with those in the PLA group. Blood lactate concentration [La⁺] levels showed no differences between groups in any of the repetitions (<i>p</i> > .05, unclear), and we observed an increase in 100-m times for both BJ and PLA (BJ: <i>p</i> = .014, MD = -1.51 s; PLA: <i>p</i> = .029, MD = -1.57 s) after the fifth repetition. <b>Conclusion:</b> No clear differences in performance were observed in a 6 × 100-m repeated sprint test by competitive swimmers when supplementing (or not) with BJ. However, there was a trend toward a better recovery between efforts and a better tolerance of fatigue when swimmers ingested BJ.Frontiers in physiology1076295https://www.ebi.ac.uk/biostudies/studies/S-EPMC9871287biostudies-literatureEffects of beetroot juice intake on repeated performance of competitive swimmers.PMC9871287Moreno BMorencos EVicente-Campos DMunoz AGonzalez-Garcia JVeiga SfalseEffects of beetroot juice intake on repeated performance of competitive swimmers.<b>Background:</b> Beetroot juice is a sport supplement with a high level of evidence on the physical performance enhancement. However, in swimming, there is no clear data about the effects of beetroot juice on performance. <b>Objective:</b> To investigate whether an acute intake of beetroot juice (BJ) improves the performance of competitive swimmers in a repeated maximum swimming effort. <b>Method:</b> Thirteen national-level swimmers (six females and seven males), participated in this randomized, double-blind crossover study. In two different trials, swimmers ingested a 70-mL placebo shot (.04 mmol NO₃ ^-; PLA) or a 70-mL Beet-It shot (6.4 mmol of NO₃ ^-beet juice [BJ]) 3 h before undergoing a 6 × 100-m front-crawl maximal effort test with 7 min rest between each 100 m. <b>Results:</b> Overall, 100-m times showed no difference between the BJ and PLA groups (<i>p</i> = .364), although a possibly shorter time was observed for BJ in the last repetition (<i>p</i> = .104; mean difference [MD] = -.99 s, mean-based inference [MBI] = 49/51/0). Participants in the BJ condition showed a possibly lower rate of perceived exertion in the first (<i>p</i> = .242, MD = -.85, MBI = 70/28/2) and second repetitions (<i>p</i> = .165, MD = 1.15, MBI = 83/16/1), whereas Total Quality Recovery scale scores were likely higher in the first (<i>p</i> = .110, MD = 1.15, MBI = 83/16/1) and third (<i>p</i> = .082, MD = -.77, MBI = 70/29/1) repetitions compared with those in the PLA group. Blood lactate concentration [La⁺] levels showed no differences between groups in any of the repetitions (<i>p</i> > .05, unclear), and we observed an increase in 100-m times for both BJ and PLA (BJ: <i>p</i> = .014, MD = -1.51 s; PLA: <i>p</i> = .029, MD = -1.57 s) after the fifth repetition. <b>Conclusion:</b> No clear differences in performance were observed in a 6 × 100-m repeated sprint test by competitive swimmers when supplementing (or not) with BJ. However, there was a trend toward a better recovery between efforts and a better tolerance of fatigue when swimmers ingested BJ.2022-01-01T00:00:00Z20222026-04-08T10:44:20.543Z2025-04-04T11:51:34.875ZS-EPMC98712873670393510.3389/fphys.2022.1076295