Caffeine Ingestion Affects Performance in Different Parts of a Novel Multidirectional High-Intensity Intermittent...

Objective: No study has analyzed the effects of caffeine ingestion on performance during a multidirectional high-intensity intermittent exercise. Thus, we aimed to investigate the effects of caffeine ingestion during a novel repeated agility test in futsal athletes.Methods: Using a double-blind, counterbalanced, and repeated-measures design, ten athletes (mass 71.2 ± 8.7 kg, height 1.77 ± 0.05 m, body mass index 22.7 ± 1.9 km/m², body fat percentage 10.2 ± 3.7%) performed a novel repeated-bout agility test 60 min after ingesting 6 mg · kg^-1 of caffeine or cellulose (placebo).Results: Performance time decreased progressively throughout the trial in both conditions (P = 0.01; η_p² = 0.66), with a significant interaction effect (P = 0.01; η_p² = 0.35) showing a potential beneficial effect of caffeine at the beginning, followed by a decrease at the end of the test. Furthermore, magnitude of decrease in performance was more pronounced in caffeine (-9.0 ± 5.7%) compared with placebo (-4.7 ± 3.9%, P = 0.01; d = 0.88). Interestingly, magnitude-based inferences revealed a possible benefit (70%) of caffeine at the beginning, followed by likely (93%) to very likely (96%) impairments in performance during the last third of the test. Heart rate and rating of perceived effort increased in both conditions over the time (P < 0.05), with similar values between experimental conditions (P > 0.05).Conclusion: Caffeine seems to have a potential beneficial effect at the beginning, with an impaired performance during the final third of a new multidirectional high-intensity intermittent exercise in futsal athletes.