Understanding the effects of beetroot juice intake on CrossFit performance by assessing hormonal, metabolic and mechanical response: a randomized, double-blind, crossover design

Figures & data

Fig. 1 Study design. Abbreviations: 1RM: one-repetition maximum; BJ: beetroot juice; CF: CrossFit; CMJ: countermovement jump; FBS: full back squat; PL: placebo; SpO₂: arterial oxygen saturation; WB: Wall Ball; WOD: workouts of the day

Fig. 2 Number of repetitions performed after beetroot juice (BJ) and placebo (PL) intake. Abbreviations: BJ-R/3′: beetroot juice condition with 3-min rest between wall ball shots and full back squat. BJ-WR/3′: beetroot juice condition without rest between wall ball shots and full back squat. PL-R/3′: placebo condition with 3-min rest between wall ball shots and full back squat. PL-WR/3′: placebo condition without rest between wall ball shots and full back squat. ★ A significant increase in the number of repetitions performed in the first routine (with 3-min rest) compared to the second routine (without rest) in both experimental conditions (p < 0.001). ☨ A significant increase in the number of repetitions performed in the first routine (with 3-min rest) after BJ intake compared to PL condition (PL-R/3′) (p = 0.007). Data are provided as mean and error bars as 95% confidence intervals

Fig. 3 Cortisol (a), testosterone (b) and testosterone/cortisol ratio (c) after beetroot juice and placebo intake. Abbreviations: BJ: beetroot juice; PL: placebo; T/C ratio: testosterone/cortisol ratio. ★ A significant raise in testosterone and cortisol concentrations after WOD test (post-test) compared to pretest in both experimental conditions (p < 0.01). ☨ Significantly higher increase (Δ%) in cortisol concentrations after BJ intake compared to PL condition (p = 0.004). Data are provided as mean and error bars as 95% confidence intervals

Table 1 Metabolic fatigue (lactate), arterial oxygen saturation (SpO₂) and mechanical fatigue (CMJ test) produced in both experimental conditions

Fig. 4 Arterial oxygen saturation (a) and jump height (b) losses (%). Abbreviations: BJ: beetroot juice; PL: placebo; arterial oxygen saturation: SpO₂. ★ Significantly higher increase (Δ%) in SpO₂ loss (p = 0.01) and vertical jump height loss (p = 0.02) after BJ intake compared to PL condition. Data are provided as mean and error bars as 95% confidence intervals

Availability of data and materials

Data are presented in the manuscript, further information available upon request.