The ability of nitrate (NO₃⁻)-rich beetroot juice (BJ) to improve exercise depends on training status. However, the mechanisms are understudied. The aim of this study was to investigate the impact of acute BJ supplementation on the Special Judo Fitness Test (SJFT) outcomes in elite and recreational judokas. Forty judo athletes (17 elite and 23 recreational) completed two SJFT sessions after drinking either BJ or a placebo in a randomized, double-blind, placebo-controlled crossover design. Plasma NO₃⁻ and lactate, tissue saturation index (TSI) and SJFT outcomes were measured. Plasma NO₃⁻ increased after BJ intake in both groups (p 0.05). BJ increased post-SJFT TSI (elite: 2.6 ± 3% vs. recreational: 4.55 ± 2.6%) and reduced HR₁ (elite: − 5.6 ± 3.3% vs. recreational: − 9.8 ± 4.7%) and SJFT index (elite: − 2.7 ± 5.6% vs. recreational: − 6 ± 5.8%) overall (p < 0.001 compared to placebo), with greater effects in recreational athletes (p < 0.05). BJ also decreased post-SJFT lactate only in recreational athletes (p < 0.01). Higher maximal oxygen uptake correlated with smaller BJ-induced improvements in lactate (r = − 0.57, p < 0.001), HR₁ (r = − 0.50, p < 0.001), SJFT index (r = − 0.43, p < 0.01), and TSI during the third period of SJFT effort (r = − 0.5, p < 0.001) and during 1-min recovery (r = − 0.35, p < 0.05). BJ primarily attenuates the physiological cost and enhances recovery-related markers during the judo performance, rather than directly increasing the performance, with responsiveness modulated by training status.
Güler et al. (Mon,) studied this question.