Citrulline Malate Fails to Improve German Volume Training Performance in Healthy Young Men and Women

Abstract

Citrulline malate (CM) is purported to buffer lactic acid, enhance oxygen delivery, and attenuate muscle soreness. Anaerobic exercise trials with CM have produced conflicting results. The aim of the current investigation was to test the efficacy of CM on resistance training (RT) with the hypothesis that CM would improve performance. A double-blind, counter-balanced, randomized control trial was utilized to assess the effects of CM on RT. Nineteen participants (8 female) (25.7 ± 7.7 years), regularly engaged in RT, consumed either 8 g of CM (1.1:1 ratio) or a placebo (6 g citric acid). Participants attempted to perform a German Volume Training (GVT) protocol comprising 10 sets of 10 repetitions of barbell curls at 80% of their one repetition maximum. Repeated ANOVA suggested no effect of CM on RT performance (treatment × time × order p = .217). There was no difference (p = .320) in the total number of reps over the 10 sets (CM median = 57, IQR 45-73; placebo median = 61, IQR 51-69). Blood lactate and creatine kinase did not differ between CM and placebo (p > .05). Finally, total muscle soreness was reduced significantly in CM compared to placebo (treatment × time × order p = .004). These results require corroboration; an ergogenic benefit is yet to be established, and weight trainers should exercise caution when assessing the efficacy of CM. Future research should focus on the potential effects of loading doses of CM.

Keywords: NOS; arginine; creatine kinase; muscle soreness; resistance training; supplementation.