On the other hand, the ingestion of two or three servings of energy drink (equivalent to ~2-3 mg of caffeine per kg) improved [24, 34] or tended to improve [25] physical performance. These outcomes combined with the results of the present investigation suggest that the physical benefits attributed to caffeine-containing energy drinks

are present with at least 3 servings, equivalent to ~3 mg/kg of caffeine. The effects of MK1775 caffeine ingestion on muscle strength have been previously investigated during the realization of either isometric maximal voluntary contractions (MVC) or isotonic 1 RM tests [12]. Overall, the ingestion of ~6 mg/kg of caffeine raised maximal force production during both assessments, while lower caffeine doses have not been extensively studied (see review [28]). Regarding muscle power production and caffeine

Saracatinib supplier ingestion, most studies have used a 4–30 s maximal cycling test. In these studies, the results are confusing since ~6 mg/kg of caffeine increased [6, 35–37] or did not changed [38–43] maximal cycling power with similar 3-to-7 mg/kg caffeine doses. The experimental design used for the present investigation contains some novelties in comparison to previous studies about caffeine and muscle performance. First, we have selected a power-load test to assess muscle performance after caffeine ingestion instead of single-resistance trials (i.e., MVC, 1RM, Wingate test, etc). This test includes maximal concentric contractions over a wide range of resistances and thus, it allows a better identification of maximal power and strength production. Similar power-load tests have been successfully used to assess the effect of training [44] and age [45] on muscle performance. Second, we have used two doses of caffeine to assess the dose–response benefits of this substance on muscle performance. These

doses (1 and 3 mg/kg) were chosen Liothyronine Sodium based on previous publications on endurance performance tests in which the ingestion of 3 to 9 mg/kg of caffeine produced comparable benefits, while 1 mg/kg was found to be non ergogenic [7, 14]. Third, we have measured the effects of caffeine ingestion on upper-body and lower-body exercises. It has been suggested that lower-body muscles are more sensitive to caffeine ingestion due to their lower activation level [28]. With this experimental design, we can conclude that caffeine increases both maximal muscle strength and muscle power even with a dose of 3 mg/kg. In addition, the effects of caffeine on lower-body and upper-body muscles were alike. Originally, the ergogenic effects of caffeine on physical performance were attributed to an enhancement of muscle fat oxidation and thus to a better glycogen sparing capacity derived from the intake of this substance [46].