Effects of an Acute High Dose of Caffeine on Physiological Responses and Performance During a Strength-Focused CrossFit® Workout: A Randomized, Double-Blind, Crossover Study

<b>Background</b>: Several nutritional strategies have been used to enhance performance in CrossFit^® training. This randomized, double-blind, crossover study aimed to investigate the acute effects of caffeine consumption on physiological responses and performance during a strength-focused CrossFit workout. <b>Methods</b>: Twelve healthy men, aged 29.2 ± 3.8 years (mean ± SD throughout), with 4.9 ± 1.9 years of CrossFit experience, completed two sessions of a specific CrossFit training program (four rounds of five exercises, 50 s exercise/10 s rest), 60 min after consuming either anhydrous caffeine (7.1 ± 0.7 mg/kg of body mass) or a placebo, aiming to perform as many repetitions as possible. The washout period was at least seven days. At the end of each round, subjective perception of fatigue was recorded using the Borg scale. Blood lactate concentration was measured before and immediately after completing the training session using a portable lactate analyzer. Data were analyzed by factorial ANOVA with repeated measures. <b>Results</b>: Caffeine had a negative effect on the number of sit-up repetitions in the fourth round (<i>p</i> = 0.012), while it did not affect any other performance parameter, rating of perceived exertion, or lactate concentration compared with the placebo. <b>Conclusions</b>: The results of the present study suggest that caffeine consumption does not improve performance in CrossFit training.