Bruno Travassos

Interpersonal coordination and ball dynamics in futsal (indoor football).

Here, we report an investigation of the patterned movement behavior of players for a specific sub-phase of the game of futsal, namely when the goalkeeper for the attacking team is substituted with an extra outfield player. The movement trajectories of the ball and players were recorded in both lateral and longitudinal directions and investigated using relative phase analysis. Some differences in phase relations between different playing dyads were noted, indicating specificity of phase attractions, or otherwise, for certain players. In general terms, the defenders demonstrated strong in-phase attractions with the ball and with each other, whereas weaker phase attractions, indicated by increased relative phase variability, were observed for the attackers and ball, as well as between attackers themselves. These results demonstrate different coordination dynamics for the defending and attacking dyads, from which we interpret evidence for different playing sub-systems consistent with different team objectives linked together in an overarching game structure. In keeping with dynamical systems theory for complex systems, we view this sub-phase of futsal as being characterized by coordinated behavior patterns that emerge as a result of self-organizing processes. These dynamic patterns are generated within functional constraints, with players and teams exerting mutual influence on each other.

Performance analysis in team sports: advances from an ecological dynamics approach

Capacity to produce data for performance analysis in sports has been enhanced in the last decade with substantial technological advances. However, current performance analysis methods have been criticised for the lack of a viable theoretical framework to assist on the development of fundamental principles that regulate performance achievement. Our aim in this paper is to discuss ecological dynamics as an explanatory framework for improving analysis and understanding of competitive performance behaviours. We argue that integration of ideas from ecological dynamics into previous approaches to performance analysis advances current understanding of how sport performance emerges from continuous interactions between individual players and teams. Exemplar data from previous studies in association football are presented to illustrate this novel perspective on performance analysis. Limitations of current ecological dynamics research and challenges for future research are discussed in order to improve the meaningfulness of information presented to coaches and managers.

Practice task design in team sports: representativeness enhanced by increasing opportunities for action.

Abstract This study investigated effects of manipulating the number of action possibilities in a futsal passing task to understand the representativeness of practice tasks designs. Eight male senior futsal players performed a passing task in which uncertainty on passing direction for the player in possession of the ball was increased in four conditions and compared with passing data from a competitive match. Performance during a passing task and competitive futsal performance was compared using ball speed and passing accuracy data. Ball speed data were analysed by approximate entropy (ApEn) to capture their regularity in each of the four conditions and during competitive performance. Significantly high levels of regularity were observed in predetermined passes in comparison with emergent passes (i.e., passes with high number of possibilities for action). Similar results for ball speed regularity were observed between practice tasks with a high number of possibilities for action (i.e., emergent passes) and competitive performance. Similar results were observed for passing accuracy in practice tasks with a high number of possibilities for action compared to competitive performance. Increases in the number of action possibilities during practice improved action fidelity of tasks in relation to competitive performance.

Spatiotemporal coordination behaviors in futsal (indoor football) are guided by informational game constraints

This report investigated the behavioral dynamics of teams in futsal game practice when the goalkeeper of the attacking team is substituted for an extra outfield player. To this end, the lateral and longitudinal displacements of the ball and both teams, as well as their kinematics expressed in angles and radial distances from the goal center, were obtained and subjected to relative phase analysis. The results demonstrated (a) stronger phase relations with the ball for the defending team than the attacking team for both coordinate systems, (b) phase relations between each team and ball, and, to a lesser extent, between teams themselves, produced greater stabilities in the lateral (side-to-side) direction than the longitudinal (forward-backward) direction, and (c) phase attractions were most pronounced for the defending team and ball when using angles as a measure of association, indicating ball position and goal location as key informational constraints for futsal game behavior. These findings advance understanding of self-organizing sports game dynamics with implications for sports practice.

Interpersonal coordination tendencies shape 1-vs-1 sub-phase performance outcomes in youth soccer

Abstract This study investigated the influence of interpersonal coordination tendencies on performance outcomes of 1-vs-1 sub-phases in youth soccer. Eight male developing soccer players (age: 11.8 ± 0.4 years; training experience: 3.6 ± 1.1 years) performed an in situ simulation of a 1-vs-1 sub-phase of soccer. Data from 82 trials were obtained with motion-analysis techniques, and relative phase used to measure the space-time coordination tendencies of attacker-defender dyads. Approximate entropy (ApEn) was then used to quantify the unpredictability of interpersonal interactions over trials. Results revealed how different modes of interpersonal coordination emerging from attacker-defender dyads influenced the 1-vs-1 performance outcomes. High levels of space-time synchronisation (47%) and unpredictability in interpersonal coordination processes (ApEn: 0.91 ± 0.34) were identified as key features of an attacking players success. A lead-lag relation attributed to a defending player (34% around −30° values) and a more predictable coordination mode (ApEn: 0.65 ± 0.27, P < 0.001), demonstrated the coordination tendencies underlying the success of defending players in 1-vs-1 sub-phases. These findings revealed how the mutual influence of each player on the behaviour of dyadic systems shaped emergent performance outcomes. More specifically, the findings showed that attacking players should be constrained to exploit the space-time synchrony with defenders in an unpredictable and creative way, while defenders should be encouraged to adopt postures and behaviours that actively constrain the attackers actions.

Interpersonal coordination tendencies supporting the creation/prevention of goal scoring opportunities in futsal

Abstract Research on 1vs1 sub-phases in team sports has shown how one player coordinates his/her actions with his/her opponent and the location of a target/goal to attain performance objectives. In this study, we extended this approach to analysis of 5vs5 competitive performance in the team sport of futsal to provide a performance analysis framework that explains how players coordinate their actions to create/prevent opportunities to score goals. For this purpose, we recorded all 10 futsal matches of the 2009 Lusophony Games held in Lisbon. We analysed the displacement trajectories of a shooting attacker and marking defender in plays ending in a goal, a goalkeepers save, and a defenders interception, at four specific moments during performance: (1) assisting attackers ball reception and (2) moment of passing, (3) shooters ball reception, and (4), shot on goal. Statistical analysis showed that when a goal was scored, the defenders angle to the goal and to the attacker tended to decrease, the attacker was able to move to the same distance to the goal alongside the defender, and the attacker was closer to the defender and moving at the same velocity (at least) as the defender. This study identified emergent patterns of coordination between attackers and defenders under key competitive task constraints, such as the location of the goal, which supported successful performance in futsal.

Coordination tendencies are shaped by attacker and defender interactions with the goal and the ball in futsal.

This study examined how the location of the goal and ball constrained the interpersonal coordination tendencies emerging of attacker-defender dyadic systems in team sports. Additionally, we analysed how the positioning of defenders constrained the emergent coordination tendencies between the ball carrier and supporting teammates. To investigate these tendencies in team sports, ten futsal games were filmed to observe inter-individual interactions. Movement trajectories of players and ball were digitized during 52 outfield attacker-defender interactions involving thirteen goal-scoring sequences. Relative phase was used as a measure to express participant coordination tendencies in these dyadic systems (in-phase or symmetry - 0°; anti-phase or anti-symmetry - 180°). Stable in-phase patterns of coordination emerged between specific values of an attackers distances to defenders and the goal (19% frequency from 0° to 29° of phase relations) and between specific values of distances of ball carriers to defenders and teammates (14% frequency from 0° to 29° of phase relations). A stable pattern of coordination of -60° emerged between values of an attackers distances to defenders and the ball (18% frequency from 0° to 29° of phase relations). Distances of attackers to the goal and ball, and distances of ball carriers to defenders, seemed to be coupled in a specific manner to guide interpersonal coordination tendencies between players during competitive performance in the team sport of futsal.

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.

Improving Passing Actions in Team Sports by Developing Interpersonal Interactions between Players

We investigated how interpersonal coordination tendencies of players in Futsal constrained performance of passing actions. To achieve this aim, we digitized 24 digital video film clips of attacking phases in competitive Futsal games. Values of interpersonal distance between players were recorded from the moment at which a teammate performed the pass to the ball carrier, to the moment of pass initiation by the ball carrier. Our results revealed that performance of passing actions was constrained by a convergence in interpersonal distance values between players. Pass efficacy seemed to be constrained by changes in interpersonal distance values between the ball carrier and the 2nd defender without a correspondent adaptation in ball velocity. Based on our results, we suggest three training phases for developing passing performance in Futsal by manipulating key constraints in the performance environment relative to the interpersonal distance values between players.

Eco-Dynamics Approach to the study of Team Sports Performance~!2009-07-05~!2009-11-01~!2010-04-29~!

The main goal of performance analysis in team sports has been the identification of data frequencies or sequences of actions in a temporal line, based on the assemblage of numerous discrete variables. This focus may be deemed as not displaying the foremost team sport feature, i.e., the dynamics of the interaction between two teams. In order to better understand the dynamic patterns of the game, the methods commonly applied must be furthered in a functional perspective. Underpinned in the Ecological Dynamics approach to decision making in sport, this paper regards performance analysis as a process of synthesis and parsimonious explanation of game’s functional nature. Accordingly, we argue the importance of the following three aspects: i) game must be viewed considering different levels of analysis; ii) there is a functional role of variability in players’ behaviour that must be included in the analysis; iii) human behaviour is better understood if we consider how the dynamics reflects individual and collective perceptual-action couplings.