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Here you can find the papers Luís Vilar and colleagues have recently published in scientific journals. Press the red button and get full access to each content. Don't forget to contact the author and tell him your opinion. Enjoy!
Constraints on competitive performance of attacker-defender dyads in team sports
Previous research on coordination dynamics of 1 vs. 1 sub-phases in team sports has reported stable emergent patterns of coordination in the displacement trajectories of attackers and defenders. The aim of this study was to use attacker–defender interactions in competitive team match-play to investigate how the locations of the goal and ball constrain the pattern- forming dynamics of attacker–defender dyadic systems. Ten high-level futsal matches were filmed and 13 goal sequences selected for analysis. Displacements of the players and the ball were filmed and digitized from 52 attacker–defender dyadic system interactions. Results showed that, although attackers and defenders exhibited similar angular orientations to the goal, the latter always remained closer to the goal than attackers. Observations revealed that in-phase patterns of coordination emerged from changes to both the distances and angles of attackers and defenders to the goal. Attackers always remained closer to the ball than defenders, while the latter exhibited a lower angle to the ball than attackers. A pattern of in-phase coordination modes emerged between the attackers and defenders’ distances and angles to the ball. This study helps us to understand interpersonal interactions in team sports by explaining how attackers and defenders use information about their relative positioning to the goal and the ball to perform successfully.
Science of winning soccer: Emergent pattern-forming dynamics in Association Football
Quantitative analysis is increasingly being used in team sports to better understand performance in these stylized, delineated, complex social systems. Here we provide a first step toward understanding the pattern-forming dynamics that emerge from collective offensive and defensive be- havior in team sports. We propose a novel method of analysis that captures how teams occupy sub-areas of the field as the ball changes location. We used this method to analyze a game of association football (soccer) based upon a hypothesis that local player numerical dominance is key to defensive stability and offensive opportunity. We found that the teams consistently allocated more players than their opponents in sub-areas of play closer to their own goal. This is consistent with a predominantly de- fensive strategy intended to prevent yielding even a single goal. We also find differences between the two teams’ strategies: while both adopted the same distribution of defensive, midfield, and attacking players (a 4 : 3 : 3 system of play), one team was significantly more effective in maintaining both de- fensive and offensive numerical dominance for defensive stability and offensive opportunity. That team indeed won the match with an advantage of one goal (2 to 1) but the analysis shows the advantage in play was more pervasive than the single goal victory would indicate. Our focus on the local dynamics of team collective behavior is distinct from the traditional focus on individual player capability. It supports a broader view in which specific player abilities contribute within the context of the dynamics of multiplayer team coordination and coaching strategy. By applying this complex system analysis to association football, we can understand how players’ and teams’ strategies result in successful and unsuccessful relationships between teammates and opponents in the area of play.
Interpersonal coordination tendencies supporting the creation/prevention of goal scoring opportunities in futsal
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 goalkeeper’s save, and a defender’s interception, at four specific moments during performance: (1) assisting attacker’s ball reception and (2) moment of passing, (3) shooter’s ball reception, and (4), shot on goal. Statistical analysis showed that when a goal was scored, the defender’s 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.
The need for ‘representative task design’ in evaluating efficacy of skills tests in sport: A comment on Russell, Benton and Kingsley (2010)
Russell, Benton and Kingsley (2010) recently suggested a new association football test comprising three different tasks for the evaluation of players’ passing, dribbling and shooting skills. Their stated intention was to enhance ‘ecological validity’ of current association football skills tests allowing generalisation of results from the new protocols to performance constraints that were ‘representative’ of experiences during competitive game situations. However, in this comment we raise some concerns with their use of the term ‘ecological validity’ to allude to aspects of ‘representative task design’. We propose that in their paper the authors confused understanding of environmental properties, performance achievement and generalisability of the test and its outcomes. Here, we argue that the tests designed by Russell and colleagues did not include critical sources of environmental information, such as the active role of opponents, which players typically use to organise their actions during performance. Static tasks which are not representative of the competitive performance environment may lead to different emerging patterns of movement organisation and performance outcomes, failing to effectively evaluate skills performance in sport.
The Role of Ecological Dynamics in Analysing Performance in Team Sports
Performance analysis is a subdiscipline of sports sciences and one- approach, notational analysis, has been used to objectively audit and describe behaviours of performers during different subphases of play, providing additional information for practitioners to improve future sports performance. Recent criticisms of these methods have suggested the need for a sound theoretical rationale to explain performance behaviours, not just describe them. The aim of this article was to show how ecological dynamics provides a valid theoretical explanation of performance in team sports by explaining the formation of successful and unsuccessful patterns of play, based on symmetry-breaking processes emerging from functional interactions between players and the performance environment. We offer the view that ecological dynamics is an upgrade to more operational methods of performance analysis that merely document statistics of competitive performance. In support of our arguments, we refer to exemplar data on competitive performance in team sports that have revealed functional interpersonal interactions between attackers and defenders, based on variations in the spatial positioning of performers relative to each other in critical performance areas, such as the scoring zones. Implications of this perspective are also considered for practice task design and sport development programmes.
Assumptions for the conceptualization of football training: a study with coaches with certificate level IV
The training methodology of Football Association is based on the control of variables centered on the player (cognitive or analytical) or on variables that assess his relationship with the context (eco-dynamics or global). In this investigation we aim to understand how 24 coaches with level IV certificate conceptualize their training exercises. Thus, we built a questionnaire that aims to study the exercise in four different dimensions:(1) interaction of preparation factors, (2) guidance to a collective conceptual model, (3) nature of the exercise and (4) relation between the exercise and the competition. Results indicate that coaches assume that the tactic factor should lead the process of training and that all factors must interact simultaneously in the task. Coaches report that the collective conceptual model should be the guiding element of the training process and that exercises should be conceptualized in its direction. The decision-making training is regarded as being extremely important, although respondents are divided on how this process works. All coaches reported that both the competition analysis and the analysis of training are fundamental processes for building the consequent tasks. However, they seemed to be divided regarding the relevant information to pick up from these contexts.