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:

• arginine
• creatine kinase
• muscle soreness
• NOS
• resistance training
• supplementation

Acknowledgments

The study was designed and conducted by TNS and AJC: data were collected by TNS and AJC, and analysis of the data and interpretation were carried out by TNS and AJC. Dr. Daniel M. Allwood carried out analysis of the dietary supplement via NMR and contributed to the method section of the manuscript. Manuscript preparation was undertaken by TNS and AJC. All authors approved the final version of the article. The authors acknowledge Dr. Jeanette Gittens for blinding and counterbalancing the supplement/placebo in this investigation. The authors also acknowledge Mr. Adrien Parry for his assistance during the data collection. This study had prior approval from the Sheffield Hallam University Food Research Ethics Committee No. SBS - 252.

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the article.

About the authors

Andrew J. Chappell, PhD, Food and Nutrition Group, Sheffield School of Business, Sheffield Hallam University, Sheffield, UK. Interested in bioactive substances and their effect on exercise performance.

Daniel M. Allwood, PhD, Department of Biosciences and Chemistry, Sheffield Hallam University, Sheffield, UK. Daniel is an organic chemist and is interested in brewing and nuclear magnetic resonance spectroscopy for the identification of organic molecules.

Trevor N. Simper, PhD, Food and Nutrition Group, Sheffield School of Business, Sheffield Hallam University, Sheffield, UK. Interested in bioactive substances and their effect on exercise performance.