Effects of Serial Carbohydrate Mouth Rinsing on Repeated-Sprint Ability and Heart Rate Recovery in Fatigued Professional Soccer Players: A Randomized Crossover Trial

Carbohydrate mouth rinsing (CHO MR) can be considered a potentially ergogenic aid. Results from prior studies involving team-sport athletes are contradictory and limited by small sample sizes of professional participants. The study aimed to evaluate the effect of serial CHO MR administered before and during high-intensity sport-specific exercise on anaerobic performance indices in adult professional soccer players. Sixteen professional male soccer players (age: 24.2±4.5 years; height: 182.8±5.8 cm; body mass: 79.5±8.6 kg; BMI: 23.7±1.7) participated in a double-blind, placebo-controlled, randomized crossover trial. All participants completed two experimental sessions (CHO MR and PLA MR) in a randomized, counterbalanced order during a repeated-sprint ability test (RSAT), preceded by a battery of physical and sport-specific skill assessments. CHO MR or PLA MR solution was administered prior to the 1st, 3rd, and 5th sprints within the RSAT protocol. A difference was observed in the sixth RSAT sprint, while time was marginally improved under the CHO (p=0.0238). Heart rate measured after a two-minute rest period was significantly lower in the CHO (p=0.0259), and heart rate recovery was significantly faster (p=0.0119). CHO MR exerts a positive effect on RSAT against the background of fatigue and enhances heart rate recovery in adult professional soccer players.