The Effects of Carbohydrate Mouth Rinse on Psychophysiological Responses and Kinematic Profiles in Intermittent and Continuous Small-Sided Games in Adolescent Soccer Players: A Randomized, Double-Blinded, Placebo-Controlled, and Crossover Trial.

BACKGROUND

Mouth rinsing (MR) with a carbohydrate solution is one of the most popular methods athletes use to improve their game-based performance due to its acute ergogenic effect.

OBJECTIVES

This study aimed to evaluate the effects of the carbohydrate MR intervention on psychophysiological responses and kinematic profiles during intermittent () and continuous () 4-a-side small-sided soccer games (SSGs).

METHODS

Thirty-two adolescent soccer players (age: 16.5 ± 0.5 years) played six bouts of 4-a-side SSGs with MR or MR at 3-day intervals in a randomized, double-blinded, placebo-controlled, and crossover study design. Psychophysiological responses and kinematic profiles were continuously recorded during all games. The rating of perceived exertion (RPE), the rating scale of mental effort (RSME), and the physical enjoyment scores (PES) were also determined at the end of each game.

RESULTS

The MR induced higher psychophysiological responses such as RPE, internal training load (ITL), and RSME ( ≤ 0.05, values ranging from 0.50 to 1.04 [small to moderate effect]). Conversely, the MR induced higher PES ( ≤ 0.05, values = 1.44 [large effect]) compared to MR. Although the MR intervention led to similar improvements in the performance of 4-a-side MR and MR, there was no significant difference between the groups.

CONCLUSIONS

Our results suggest that the MR intervention can be used as an effective ergogenic supplement for acute game performance enhancement, regardless of the game's structure.