Effect of Acute Beetroot Supplementation on Exercise Performance of CrossFit® Male Athletes: Randomized, Double-blind, Placebo-Controlled Crossover Study

Abstract

The study aimed to evaluate the effect of beetroot supplementation on the number of repetitions in the Cindy test of male athletes who practice CrossFit® to improve their exercise performance. Twenty male CrossFit® athletes (age = 28 ±3 years, height = 1.71 ± 0.2 m, weight = 72.2 ± 4.2 kg) were included in a randomized, double-blind, placebo-controlled and crossover study. The participants consumed a beetroot supplement (515 mg (8.24 mmol) of nitrate) or placebo (starch) 90 min before starting the Cindy workout. Student's t-tests for paired samples were used to compare the performance between the beetroot supplement and placebo conditions and to examine for a learning effect between the first and the second sessions. No significant differences were found in performance between the beetroot supplement and the placebo conditions (17.4 ± 2.7 vs. 16.7± 2.3 rounds, t = 1.48, p = 0.078). However, a significant learning effect was determined between the first and the second session (16.6 ± 2.4 vs. 17.5± 2.6 rounds, t = 1.94, p= 0.034). Overall, the intake of 515 mg of beetroot nitrate (8.24 mmol) before a Cindy workout did not increase the number of repetitions performed. More studies are needed to confirm whether nitrate in beetroot can be used as an effective performance improvement strategy in CrossFit® male athletes, considering that a learning effect could be present in the practice of CrossFit® workouts.