Research article - (2024)23, 228 - 235
DOI:
https://doi.org/10.52082/jssm.2024.228
A Single Dose of Beetroot Juice not Enhance Performance during Intervallic Swimming Efforts
Berta Moreno-Heredero1,2, Esther Morencos1, Jorge E. Morais3,4, Tiago M. Barbosa3,4, Santiago Veiga2
1Exercise Physiology Group, Exercise and Sport Sciences, Faculty of Health Sciences, Universidad Francisco de Vitoria, Madrid, Spain
2Departamento de Deportes, Universidad Politécnica de Madrid (UPM), Madrid, Spain
3Instituto Politécnico de Bragança, Bragança, Portugal
4Research Centre for Active Living and Wellbeing (LiveWell), Instituto Politécnico de Bragança, Bragança, Portugal

Berta Moreno-Heredero
✉ Exercise Physiology Group, Exercise and Sport Sciences, Faculty of Health Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain
Email: b.moreno@ufv.es
Received: 15-12-2023 -- Accepted: 21-02-2024
Published (online): 01-03-2024

ABSTRACT

Despite the numerous scientific evidence on the topic, there is no clear and consistent answer that clarifies the true effects of beetroot juice (BJ) supplementation on different types of physical performance. This study examined whether an acute intake of BJ improves swimming performance, physiological variables of anaerobic metabolism, or subjective measures during high-intensity interval exercise with incomplete rest in competitive swimmers. Eighteen competitive swimmers (nine females and nine males) participated in this cross-over randomized, placebo-controlled, double-blind and counterbalanced study. In two trials, swimmers ingested BJ (70 mL, 6.4 mmol/400 mg NO3-) or placebo (PLA) (70 mL, 0.04 mmol/3 mg NO3-) three hours before a 2×6×100 m maximal effort with 40 seconds rest between repetitions and three minutes between blocks. The 100 m times showed no differences between groups (p > 0.05), but there was an interaction between block×repetition×condition (F5 = 3.10; p = 0.046; ηp2 = 0.54), indicating that the BJ group decreased the time of the sixth repetition of block2 compared to block1 (p = 0.01). Lactate concentration showed no differences between conditions (p > 0.05), but there was a main effect of block (ηp2 = 0.60) and a block×repetition interaction (ηp2 = 0.70), indicating higher values in block2 and increasing values between repetitions in block1. The subjective scales, perception of exertion (RPE) and Total Quality Recovery (TQR), showed no effects of condition (p > 0.05), but BJ swimmers had a greater TQR in the last repetitions of each block. In conclusion, a single dose of BJ did not enhance intermittent swimming performance or modified the physiological (lactate and heart rate) or subjective (RPE and TQR) variables; although there was a possible positive effect on the exercise tolerance at the end of effort.

Key words: Nitrate, ergogenic aids, intermittent efforts, swimming performance, exercise tolerance

Key Points
  • The effect of an acute dose of beet juice three hours before a high-intensity 2 × 6 × 100 test with reduced recovery, as typically used during training blocks, was tested in competitive swimmers.
  • The BJ supplementation did not significantly affect the overall performance of competitive swimmers or their physiological variables.
  • However, an improvement in perceived recovery (TQR) at the end of the interval effort was noted for the BJ group, suggesting an improvement in exercise tolerance that may play a role in the competitive outcome of competitive swimmers.








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