Introduction: In collective sports, under different constraints, some movement configurations or skills are more likely to occur and some are unlikely, breaking system`s replica symmetry (Hristovksi et al. 2011). The aim of this study was to determine how the number of opponents (3, 5, 6 and 7) affects the emergence of tactical and technical skills and the softly-assembled dynamics when four professional footballers play small-sided games. Methods: Four professional football players (age: 29.0 ± 3.6 years; height: 180.3 ± 7.4 cm; weight: 74.8 ± 7.9 kg) participated in a cross-sectional study. Eight small-sided games were played by a team of four players, against an opposition of 3, 5, 6 and 7 players (two times for each constraint) and video-recorded. The games were played randomly on a 40x30 metre pitch each for 3 min. Resulting trials were sequentially observed using an observational instrument with 63 categories. The data obtained was then analysed using a soft-assembled hierarchy model by means of two statistical analyses: a Principal Components Analysis (PCA) and the calculation of dynamic overlap order parameter q to determine the structure of the potential landscape of the team. Results: PCA revealed 13 primary PCs for the games against 3 and 5 opponents, 10 primary PCs for the game against 6 and 11 for the game against 7 accounting for more than 80% of the total variance. The increase in the number of opponents resulted in a decrease in the number of offensive actions and an increase in the actions focused on the space control. In defense, playing with a numerical advantage constrained the players to perform more tactical skills focused on the player with the ball. In offense, players more frequently used skills of ball transmission when playing with numerical advantage, while they used more frequently skills of ball retention when playing with numerical disadvantage. The dynamic overlap formed statistically different plateaus for each condition, being 0.165 for the game with three opponents, 0.154 against five, 0.147 against six and 0.152 against seven. Conclusions: The plateau values show a higher exploratory behaviour playing against three opponents. Constraining the game can also force the players to use specific technical or tactical skills. Coaches should be aware of these stimuli variability responses when planning the training tasks.
© Copyright 2014 19th Annual Congress of the European College of Sport Science (ECSS), Amsterdam, 2. - 5. July 2014. Published by VU University Amsterdam. All rights reserved.