Caffeine and nitrates have both been reported to enhance performance in power efforts; however, it is not clear which supplement is most effective. The aim of this study was to compare the effects of caffeine and nitrates on the performance of semi-professional soccer players during different fitness tests. Ten male soccer players in a randomized crossover design were assigned to receive caffeine (5 mg/kg body mass) (CG), nitrate ((250 mL/150 mg of NO3−) (NG), or a placebo (PG) on three different occasions. In each treatment, the participants performed the following tests: 10 m and 30 m sprints, the Illinois agility test, a countermovement jump test, a squat jump test, and a repeated sprint test (6 × 40 m). Caffeine boosted performance in jumps (CMJ: CGvsPG, p = 0.018; SJ: CGvsPG, p = 0.045 and CGvsNG, p = 0.001) and limited the decrease in performance in the RSA test (CGvsPG, p = 0.012). Nitrates limited the decrease in performance in the RSA test (NGvsPG, p = 0.035). In conclusion, the two supplements limited the decrease in performance in the test of repeated sprints, with caffeine showing a greater effect. Among the other tests, only caffeine improved performance, and only in the jumps. Thus, we can conclude that supplementation with caffeine 1 h before these kinds of activities at a dosage of 5 mg/kg of body weight can enhance performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.