Does team size affect Scottish male academy soccer player technical, locomotor and psychosocial outcomes during age and maturity bio-banded small-sided games?

The timing of the adolescent growth spurt (i.e. peak height velocity [PHV]) varies greatly, causing significant differences in maturity-related anthropometric and physical development among chronologically age-categorised youth soccer players. These differences can lead to a maturity-selection bias favouring early maturing players. Using fifty-three players from two professional Scottish soccer academies, this study examined the effects of team size (4v4, 5v5, and 6v6) and bio-banding (i.e. grouping players by maturity status) on players technical (i.e. touches, releases, possessions), physical (i.e. distance covered, accelerations/decelerations), and psychological (i.e. confidence, competitiveness, positive attitude) performance during small-sided games, using foot-mounted inertial measurement units (F-IMU) and coach observations. Data were analysed using multivariate ANOVA. During maturity-matched games, technical actions decreased as team size increased. More mature players displayed greater technical actions in 4v4 compared to 6v6. Maturity-mismatched games revealed significant technical action differences for less mature players, particularly in 4v4 formats. More mature players covered greater high-intensity distances in maturity-matched and mismatched 6v6 games. Psychological scores were higher for more mature players in smaller team sizes (4v4), whereas less mature players showed consistent psychological scores across all formats. Smaller team sizes and maturity-matched bio-banding formats enhanced technical actions and psychological characteristics, particularly for more mature players.