ABSTRACTBackgroundMouth-rinsing with ergogenic solutions such as carbohydrate and caffeinated drinks has been considered among athletes as a practical nutritional strategy. Therefore, this study aimed to determine the effect of repeated coffee mouth-rinsing (CMR) doses on specific performances of futsal players.MethodTwenty-four male futsal players randomly participated in this randomized, double-blind, and crossover design study. During the intervention, participants were randomly placed in four different conditions including 1. low-dose CMR (LDC,n= 6, ~60 mg caffeine); 2. high-dose CMR (HDC,n= 6, ~125 mg caffeine); 3. decaffeinated CMR (PLA,n= 6, ~10 mg caffeine); and 4. no CMR (CON,n= 6). Vertical jump height was measured at baseline, baseline after CMR (baseline-CMR), immediately after the intermittent futsal endurance test (FIET) (IA-FIET), 5 min after the FIET (5”A-FIET) and 10 min after the FIET (10”A-FIET). Perceived fatigue was also measured by visual analogue scale (VAS) at baseline, IA-FIET, 5”A-FIET, and 10”A-FIET. CMR was also performed at baseline, during FIET (Repeated between levels), and 10’A-FIET. The collected data were analyzed (with SPSS software) by one- and two-way repeated measure ANOVA and Bonferroni post hoc test atP< 0.05 level.ResultsThe findings of the present study illustrated that the perceived fatigue in IA-FIET increased significantly compared to the baseline which was accompanied by a significant decrease in 5”A-FIET and 10”A-FIET compared to IA-FIET (P< 0.05), and no significant difference was observed between conditions in the baseline, IA-FIET, 5”A-FIET, and 10”A-FIET (P> 0.05). However, HDC and LDC rose significantly the distance covered in FIET compared to CON and PLA (P< 0.05). In addition, HDC increased the FIET performance more than LDC (P< 0.05). Although there was no difference between any of the conditions at baseline (P> 0.05), baseline-CMR increased significantly the vertical jump height (P< 0.05). At IA-FIET, vertical jump height decreased to baseline levels in CMR conditions but increased in 5”A-FIET, which remained constant until 10”A-FIET (P< 0.05). In addition, vertical jump height in HDC and LDC conditions was significantly higher than CON in IA-FIET, 5”A-FIET, and 10”A-FIET.ConclusionThis study showed that repeated CMR with low and high doses is a useful strategy to improve specific futsal performance. However, higher dose CMR appears to have more profound effects on performance improvement than lower doses.