The effect of a pre-workout energy supplement on acute multi- joint resistance exercise was examined in eight resistance-trained college-age men. Subjects were randomly provided either a placebo (P) or a supplement (S: containing caffeine, taurine, glucuronolactone, creatine, β-alanine, and the amino acids; leucine, isoleucine, valine, glutamine and arginine) 10 minutes prior to resistance exercise. Subjects performed 4 sets of no more than 10 repetitions of either barbell squat or bench press at 80% of their pre-determined 1 repetition- maximum (1RM) with 90 seconds of rest between sets. Dietary intake 24 hours prior to each of the two training trials was kept constant. Results indicate that consuming the pre-workout energy drink 10 minutes prior to resistance exercise enhances performance by significantly increasing the number of repetitions successfully performed (p = 0.022) in S (26.3 ± 9.2) compared to P (23.5 ± 9.4). In addition, the average peak and mean power performance for all four sets was significantly greater in S compared to P (p < 0.001 and p < 0.001, respectively). No differences were observed between trials in subjective feelings of energy during either pre (p = 0.660) or post (p = 0.179) meaures. Similary, no differences between groups, in either pre or post assessments, were observed in subjective feelings of focus (p = 0.465 and p = 0.063, respectively), or fatigue (p = 0.204 and p = 0.518, respectively). Results suggest that acute ingestion of a high-energy supplement 10 minutes prior to the onset of a multi-joint resistance training session can augment training volume and increase power performance during the workout. Key pointsConsumption of a pre-workout energy supplement containing caffeine, taurine, glucuronolactone, creatine, β-alanine, and amino acids consumed 10 minutes prior to a bout of resistance exercise enhances the total number of repetitions performed during the exercise bout.Power outputs for each repetition during the workout were significantly greater when using the supplement compared to placebo.Ingestion of supplement did not have any significant effect on subjective measures of fatigue, energy and focus.
Keywords: Ergogenic aid; caffeine; nutritional supplement; resistance exercise.