The ergogenic effects of carbohydrate (CHO) and caffeine (CAF) mouth rinse (MR) methods on anaerobic performance remains unclear. Therefore, the aim of this study was to investigate the effects of CHO, CAF, and CHO + CAF combination solutions in mouth on repeated vertical jumping (RVJ) performance in highly trained male athletes. Eight male athletes (mean age: 22 years) underwent test sessions four times with minimum 24-h intervals under fasting conditions. Participants rinsed their mouths with four different 25-ml solutions, namely, CHO (6.4% maltodextrin = 1.6 g), CAF (1.2% caffeine = 300 mg), placebo (PLA, saccharin), or CHO + CAF (6.4%+1.2%) combination, for 10 s and performed a 30-s RVJ test twice with a 5-min interval. Peak power output, vertical jump height, blood lactate level, fatigue index, and rate of perceived exertion of the RVJ tests for different intervention sessions were compared. The statistical significance level was set at p ≤ 0.05. Analyses demonstrated that CHO- (Δ: 3.4), CAF- (Δ: -0.8), and CHO + CAF-MR (Δ: -1.8) interventions led to similar RVJ performance changes compared to PLA. All differences in the dependent variables were statistically insignificant and had moderate and lower effect sizes between interventions (p > 0.05, g < 0.94). Our study did not elicit sufficient evidence to recommend highly trained male athletes the use of CHO- and CAF-MR separately or in combination to enhance jump performance. However, the fact that some differences have medium to large effect sizes suggests that the issue is still worth to be a potential topic for further research.Highlights Effects of CHO + CAF-MR on anaerobic performance in highly trained athletes have not been investigated using performance tasks requiring high technical skills.There is not enough evidence to suggest that CHO, CAF and CHO + CAF-MR interventions have beneficial effects on RVJ performance compared to PLA in highly trained male athletes.Some statistically insignificant differences have medium to large effect sizes. Therefore, the issue is still worth to be a potential topic for further research.
Keywords: Ergogenic effect; fatigue index; lactate; placebo; power output; vertical jump.