Writing in the European Journal of Sports Science, researchers from Dublin City University report that three days of supplementation with citrulline malate (CM) before a repetitive sprint exercise test led to better performance for male university-level team sport athletes.
“The present study observed that 3 days of 8 g daily of CM supplementation attenuated the sprint performance decrement that occurred during a 10 repetition 40 m MST employed as a test of short-duration (5 min) high-intensity exercise performance in male university-level team sport athletes,” wrote Vinicius Faria and Dr. Brendan Egan.
“The outcomes of this study suggest that short-term CM supplementation could be beneficial for team sport athletes who perform short-duration high-intensity efforts, such as soccer, Gaelic games, field hockey and rugby.”
Citrulline
Citrulline malate (CM) is a combination of L-citrulline and malic acid. L-citrulline is among one of the most common ingredients found in commercially available pre-workout supplements, included in about 70% of products surveyed on the market in 2019.
Approximately 85% of orally ingested L-citrulline is converted into L-arginine via the citrulline-NO cycle. L-arginine is the precursor for the synthesis of nitric oxide (NO), a potent vasodilator that may improve blood flow to and from the muscle. In addition to the L-arginine NO pathway, citrulline malate may also exert ergogenic benefits via ammonia detoxification through the urea cycle to improve muscle function and attenuate fatigue, and also via the malate component, which may boost energy production and increase the rate of ATP production.
While there is data supporting citrulline malate in many sports nutrition applications, Faria and Egan noted that their new study “addresses a knowledge gap around the ergogenic potential of citrulline malate (CM) in repeated sprint running performance.”
Study details
Thirteen male university-level team sport athletes were recruited to participate in the new study, which used the CM1000 ingredient from ROS Nutrition. The men were randomly assigned to receive either 8 g per day of CM or placebo for three days. On the third day, the participants were subjected to 10 repetitions of 40 m maximal shuttle runs. This was followed by a seven-day washout period before the participants were crossed over to the other intervention.
Faria and Egan reported that citrulline malate was associated with an improvement in repeated sprint performance, as shown by a lower sprint performance decrement (4.7% for CM, compared to 6.10% for placebo). They also found that the fastest sprint times were improved following CM supplementation (8.2 seconds versus 8.3 seconds for placebo).
However, there were no differences between the two interventions for average sprint time, slowest sprint time, blood lactate levels or heart rate.
Despite the general benefits of citrulline malate on sprint performance, the researchers noted that 30% of the participants experienced declines compared to placebo.
“Such observations could be explained by the inter-individual response to supplement use and the influence of factors such as sex, genetic differences and training status,” they stated. “In practical terms, this suggests that individual athletes should, where possible, test the ergogenic potential of CM for themselves in an ecologically-valid test of their own performance.”
Source: European Journal of Sports Science
Published online ahead of print, doi: 10.1002/ejsc.12090
“Effects of 3 days of citrulline malate supplementation on short-duration repeated sprint running performance in male team sport athletes”
Authors: V.S. Faria, B. Egan