Effects of carbohydrate mouth rinse on performances of small-sided games in young male soccer players: A comparison between small and large pitch sizes

This study aimed to evaluate the effects of the carbohydrate (CHO) mouth rinse (MR) intervention on performances in young male soccer players during small (S) and large (L) pitch sizes of 4-a-side small-sided soccer games (SSG). Sixteen amateur male soccer players (age: 16.9 ± 0.3 years; height: 173.2 ± 4.6 cm; body mass: 62.4 ± 4.9 kg) played three bouts of 4-a-side SSG with S or L size sided at 3-day intervals in a randomized, double-blinded, placebo-controlled, and crossover study design. The rating of perceived exertion (RPE), the rating scale of mental effort (RSME), and the physical enjoyment scores (PES) were determined at the end of each game. Heart rate (HR) and total distance responses were continuously recorded during all games. Repeated measures analysis of variance was used to compare interactions and main effects on psychophysiological responses and kinematic profiles between the SSG-S and SSG-L pitch sizes. SSG-S with the MR group induced higher RPE responses (p ≤ 0.05, d values 1.55 [large effect]) compared to SSG-L with the MR group. Conversely, SSG-L with MR group induced higher total distance covered and successful pass (p ≤ 0.05, d values ranging from 0.29 to 5.09 [small to very large effect]) compared to SSG-S with MR group. Our results support that the CHO-MR intervention could not be used as an effective ergogenic supplement for enhancing the performance of SSG, regardless of the pitch sizes.