Effects of acute L-arginine supplementation on the performance of recreationally trained Crossfit® males: a randomized double-blind placebo-controlled trial

The ergogenic effects of L-arginine endure throughout a range of exercise modalities; however, there is limited information proving its effectiveness during CrossFit® programs. The impacts of L-arginine supplementation on CrossFit® capability were investigated in this study. Sixteen recreationally trained CrossFit® men (22.5 ± 2.8 years, 1.8 ± 2.7 years of experience) participated in a double-blind, crossover study. All participants performed three sessions spaced one week apart to allow washout, supplemented with either L-arginine (dose A: 0.15 g/kg body mass; dose B: 6 g) or a placebo 60 minutes before exercise. The participants were instructed to perform "Cindy," which is a standardized CrossFit® benchmark workout consisting of the maximum number of rounds possible of 5 pull-ups, 10 push-ups, and 15 air squats. The total number of repetitions served as the performance metric. Additional measures included lactate, blood pressure, heart rate, and pulse oximetry pre- and post-exercise. ANOVA revealed no significant performance differences among conditions (dose A: 324.4 ± 108; dose B: 343.1 ± 117; placebo: 343.1 ± 100.4, p = 0.854). A meaningful learning influence was observed after the first session (315.0 ± 111.2 vs. 343.1 ± 94.2 repetitions, p = 0.0468) but not between the second and third sessions (p = 0.4837), without observable alteration in treatment order (p = 0.3333). Results indicated that supplementation with L-arginine did not boost performance during "Cindy" in recreationally trained CrossFit® men. Familiarization sessions and discovery of various CrossFit® workouts in trained athletes should be included in upcoming studies.