Acute Citrulline Malate Supplementation Does Not Improve 1-km Time Trial Performance in Trained Female Kayak Paddlers

Introduction: Citrulline malate (CM) has been reported to enhance performance during resistance training and high-intensity exercise; however, its ergogenic effects during kayak exercise have not been investigated. This study examined the effects of acute CM ingestion on 1-km kayak ergometer time-trial (TT) performance and ratings of perceived exertion (RPE) in trained female youth kayakers. Methods: Fifteen trained female youth kayakers (age: 16.3 ± 1.1 y; body mass: 55.5 ± 6.7 kg; height: 164.3 ± 3.7 cm) completed three conditions in a randomized, double-blind, placebo-controlled crossover design: CM (8 g), placebo (PL; 6 g citric acid), and a control condition (CON; no supplement). Participants ingested CM and PL 60 min before a 1-km kayak ergometer TT. RPE (6–20) was recorded immediately upon TT completion. Results: The TT completion time differed across conditions (p = 0.001; ηp² = 0.44). Compared with CON (270.8 ± 5.31 s), TT was faster following CM (262.6 ± 4.69 s; p = 0.016) and PL (261.8 ± 4.55 s; p < 0.001), with no difference between CM and PL (p = 1.000). The RPE also differed across conditions (p = 0.025; ηp² = 0.23); however, Bonferroni-adjusted pairwise comparisons did not reach statistical significance (CON vs CM: p = 0.080; CON vs PL: p = 0.107; CM vs PL: p = 1.000). Conclusion: Acute CM supplementation did not improve 1-km kayak ergometer TT performance compared with placebo in trained female youth kayakers. The faster times observed in both CM and placebo compared with control may reflect non-specific effects (e.g., placebo/taste or pre-trial routines) and warrant further investigation.