This study examined the effects of the numbers of players involved in small-sided team games (underloading and overloading) on opportunities for maintaining ball possession, shooting at goal and passing to teammates during training. These practice constraint manipulations were assumed to alter values of key performance variables identified in previous research, such as interpersonal distances between players and time to intercept shots and passes. Fifteen male soccer players (age: 19.60±1.99 years) were grouped into three teams and played against each other in different versions of small-sided soccer games, in which the number of players was manipulated in three different conditions: 5 vs. 5, 5 vs. 4 and 5 vs. 3. Dependent variables were the values of interpersonal distance between an outfield attacker and nearest defender (ID), and the relative distance of a defender needed to intercept the trajectory of a shot (RDi shot ) or pass (RDi pass ). Statistical analyses revealed that mean ID values were significantly lower in 5 vs. 5 than in 5 vs. 4 and 5 vs. 3 conditions, and significantly lower in 5 vs. 4 than 5 vs. 3. They also revealed that mean values of RDi shot were significantly higher in 5 vs. 3 than in 5 vs. 5 conditions. Finally, results showed that the mean values of RDi pass were significantly higher in 5 vs. 3 than in 5 vs. 5. Findings revealed how task constraints in SSGs can be manipulated to vary values of key spatial and temporal performance variables (interpersonal distance and time to intercept) to influence the nature of interpersonal interactions between competing players during practice. We observed that these manipulations tended to decrease opportunities for maintaining ball possession during training when equal numbers of attackers and defenders existed in SSGs, and led to more shots and passes emerging when the number of defenders was decreased relative to attackers.Key words: Affordances, Association Football, Ball Possession, Constraints-Based Approach, Interpersonal Distance, Small-Sided Games, Soccer
INTRODUCTIONSuccessful performance in team sports like soccer is influenced by the ability of players to identify opportunities for actions from their spatial-temporal relationships with other players (both teammates and opponents) and key task constraints (such as the location of the sidelines, goal and ball) 1 . For example, an ecological dynamics analysis of performance has demonstrated how defenders decrease the values of interpersonal distance to ball carriers to dispossess them and recover ball possession 2 . To prevent this from happening and maintain ball possession, teammates use information of this closing gap in distance between ball carriers and defenders to move towards the ball carrier and afford him more passing opportunities 3 . Additionally, ball carriers have also been observed to regulate their passing and shooting actions according to the time available for the opponents to reach the trajectory path of the ball to intercept a shot at goal or a pass 4, 5 . Importa...