Tactical performance changes with equal vs unequal numbers of players in small-sided football games

This study investigated the effects of equal (GK+4-vs-4+GK) and unequal (GK+4-vs-3+GK) numbers of outfield players on tactical behaviour of players and teams in small-sided football games. Thirty sequences of play without transitions in ball possession captured from six games of five minutes duration were selected for analysis from each game condition. The movement trajectories of players, teams and ball were expressed using polar coordinates referenced on centre location of the defending goal. Tactical performance was expressed by the degree of coupling of players and teams as indicated by the relative phase for different dyad combinations and by spatial-temporal relations between players and teams using various kinematic metrics. Results showed stronger couplings in the defending dyads, defending player ball pairs and the defending team and ball (p < 0.05) for the unequal numbers game condition. Also, decreased distances between players to their team geometric centre, decreased surface areas but increased distances between team geometric centres was observed for unequal playing numbers (p<0.05). Thus, results demonstrated that numerical advantage for the attacking team changed the tactical performances of the defending and attacking players and teams, particularly the former. Knowledge on this matter provides support for coaches manipulating small-sided football games for training purposes.