Reprodutibilidade das respostas físicas de jovens jogadores de futebol durante jogos reduzidos organizados por bio-banding

Abstract

Bio-banding aims to reduce selection bias and create equity in opportunities among athletes with different maturation levels. In an environment with many variables, reproducibility emerges as a way to verify the consistency of physical responses. Therefore, the objective of this study was to analyze the reproducibility of running performance indicators during small-sided games by comparing teams with the same and different maturational status among young soccer players. The study involved 36 male soccer players, aged 12 to 15 years (U13 N=20; U15 N=16), who underwent six phases of evaluation: 1) anthropometric measurements to determine the peak height velocity (PHV) and physical tests; 2) small-sided games protocol to identify young soccer talents; 3) small-sided games with opposing teams with players of the same PHV; 4) small-sided games with opposing teams with players of different PHV; 5 and 6) repetitions of phases 3 and 4 to verify the reproducibility of physical demands (total distance covered – TD, maximum speed, average speed, and sprints). Descriptive statistics were performed using mean and standard deviation. Normality was checked by the Shapiro-Wilk test. A two-way ANOVA was conducted (factor 1 = category; factor 2 = maturation) to compare differences in anthropometric and physical variables before the game, followed by Bonferroni post-hoc test. A paired t-test was conducted to compare dependent variables between test and retest conditions. Effect size (ES) was calculated, adopting Cohen’s criterion (>0.2 = small effect; >0.5 = moderate effect; >0.8 = large effect). Pearson’s correlation was performed to analyze the relationship between physical demands during the games. Finally, an independent samples t-test was conducted to compare the delta between games with opponents of the same and different maturational stages. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 21.0 (IBM Corp., Armonk, NY, USA). The significance level was set at 5%. Overall, in both categories (U13 and U15), late-maturing players exhibited reproducible responses when playing against opponents of the same maturational status. However, when playing against opponents of different maturational statuses, physical responses decreased in the second game. For early-maturing players, the opposite was observed: responses were reproducible in games against non-matched maturation, but not against matched maturation opponents. Therefore, the results indicate that the physical responses of young soccer players during small-sided games are not consistently reproducible when considering different maturational stages. In conclusion, it was observed that physical performance variables varied significantly between the first and second game, both in confrontations with opponents of the same maturational status and in games between players with different maturation levels. This highlights the complexity of interactions between biological maturation and physical performance in the context of small-sided games.