Purpose: Citrulline malate (CM) is a nonessential amino acid that increases exercise performance in males. However, based on physiological differences between genders, these results cannot be extrapolated to females. Therefore, the purpose of this investigation was to evaluate effects of acute CM supplementation on upper- and lower-body weightlifting performance in resistance-trained females.
Methods: Fifteen females (23 ± 3 years) completed two randomized, double-blind trials consuming either CM (8 g dextrose + 8 g CM) or a placebo (8 g dextrose). One hour after supplement consumption, participants performed six sets each of upper- (i.e., bench press) and lower-body (i.e., leg press) exercises to failure at 80 % of previously established one-repetition maximum. Immediately after each set, repetitions completed, heart rate and rating of perceived exertion (RPE) were recorded.
Results: Repeated-measures analysis of variance indicated that subjects completed significantly (p = .045) more repetitions throughout upper-body exercise when consuming CM versus placebo (34.1 ± 5.7 vs. 32.9 ± 6.0, respectively). When consuming CM, similar significant (p = .03) improvements in total repetitions completed were observed for lower-body exercise (66.7 ± 30.5 vs. 55.13 ± 20.64, respectively). Overall RPE score was significantly lower (p = .02) in upper-body exercise when subjects consumed CM versus placebo (7.9 ± 0.3 and 8.6 ± 0.2, respectively). The supplement consumed exhibited no significant effects on heart rate at any time point.
Conclusions: Acute CM supplementation in females increased upper- and lower-body resistance exercise performance and decreased RPE during upper-body exercise. These data indicate that athletes competing in sports with muscular endurance-based requirements may potentially improve performance by acutely supplementing CM.
Keywords: Amino acids; Ergogenic aid; Nitric oxide; Resistance exercise; Sports nutrition; Women.