Caffeine enhances upper body strength in resistance-trained women

In a randomized manner, 15 women consumed caffeine (6 mg/kg) or placebo (PL) seven days apart. Sixty min following supplementation, participants performed a one-repetition maximum (1RM) barbell bench press test and repetitions to failure at 60% of 1RM. Heart rate (HR) and blood pressure (BP) were assessed at rest, 60 minutes post-consumption, and immediately following completion of repetitions to failure.Repeated measures ANOVA indicated a significantly greater bench press maximum with caffeine (p ≤ 0.05) (52.9 ± 11.1 kg vs. 52.1 ± 11.7 kg) with no significant differences between conditions in 60% 1RM repetitions (p = 0.81). Systolic blood pressure was significantly greater post-exercise, with caffeine (p < 0.05) (116.8 ± 5.3 mmHg vs. 112.9 ± 4.9 mmHg).These findings indicate a moderate dose of caffeine may be sufficient for enhancing strength performance in resistance-trained women.Caffeine is naturally derived from ordinary food items such as tea leaves, cocoa, coffee beans, and chocolate [1,2] and commonly consumed in the form of coffee, tea, and carbonated beverages[1,3]. Various physiological mechanisms associated with the ergogenic effects of caffeine have been described in the literature. It has been suggested that caffeine is an adenosine antagonist [4,5] and the primary mode of action may be on the central nervous system [6]. Other studies have suggested that caffeine may also have the ability to alter substrate utilization by acting to increase fat oxidation and, thus, spare glycogen utilization [7,8]. In addition, studies have also indicated enhanced secretion of β-endorphins [9] during exercise with a subsequent decrease in pain perception [10], as well as an enhanced thermogenic response [11] and alteration of neuromuscular function and/or skeletal muscular contraction [12,13].The ergogenic properties of caffeine have been extensively studied and research has indicated that low-to-moderate (~3-6 mg/kg) dosages of caffeine supplementation are ergogenic f