Researchers in Japan investigated whether a single 8 g dose of CM taken between runs improves performance in a second 100 m sprint, as well as blood lactate levels and perceived effort.
“Even small differences may be meaningful in competitive sprinting, particularly among higher-level athletes for whom outcomes are often separated by small margins,” the researchers wrote.
How citrulline malate could influence sprint performance
Short-distance sprint performance relies on fast energy systems like the ATP–phosphocreatine (ATP-PC) system, which rapidly regenerates ATP so muscles can contract explosively in the first few seconds of effort, and the anaerobic glycolysis system which breaks down glucose without oxygen to keep ATP production going.
Intense sprinting also creates fatigue by increasing acidity and ammonia in the muscles, which can reduce performance. As competitive sprinters often race multiple times in one day, the ability to repeat a maximal sprint is important, the researchers wrote.
CM is a supplement combining the amino acid citrulline and malic acid that is used to improve blood flow, reduce fatigue and enhance exercise performance. The body converts it into arginine, which can increase nitric oxide and improve blood flow, and it may also help remove ammonia and support metabolism during exercise.
However, it is unclear to what extent this improves sprinting, the researchers noted, adding that previous research has most explored the benefits of CM supplementation in the context of endurance or strength exercise.
Enhanced repeat sprint performance and reduced fatigue
To conduct their study, the researchers recruited 11 highly trained male collegiate 100 m sprinters. Each athlete completed two experimental sessions on an outdoor track under controlled and similar environmental conditions. In each session, they performed two maximal 100 m sprints, and the order of supplementation (CM or placebo first) was randomized and double-blinded.
Researchers measured sprint performance using timing gates and verified accuracy with high-speed video analysis, and blood lactate was sampled repeatedly before and after sprints to determine peak values. Perceived exertion was recorded before and after each sprint.
Results showed that there was a clear interaction between supplement type and trial. In the first sprint, both conditions performed similarly; however, in the second sprint, athletes ran slightly faster with CM than with placebo.
After sprinting, lactate increased more from the first to the second trial with CM, suggesting the athletes were able to sustain a higher glycolytic contribution, while the placebo showed almost no change. Athletes also reported feeling less fatigued after taking CM compared with the placebo.
The researchers noted that CM could influence physiology through nitric oxide production, but as they did not measure key markers like nitric oxide, ammonia or muscle oxygenation, they noted that any mechanism remains speculative.
“These findings suggest that acute CM supplementation may modestly support repeated sprint performance under extended recovery conditions,” they concluded. “However, the results should be interpreted with caution.
“The potential effects of chronic supplementation, lower doses, or different athletic populations remain unknown and warrant further investigation.”
Source: Sports. doi: 10.3390/sports14040143. “Effects of Acute Citrulline Malate Supplementation on Repeated 100 m Sprint Performance in Trained Sprinters: A Randomized Crossover Study.” Authors: Yamanaka, R. et al.
