Duarte Araújo

Movement systems as dynamical systems: the functional role of variability and its implications for sports medicine.

In recent years, concepts and tools from dynamical systems theory have been successfully applied to the study of movement systems, contradicting traditional views of variability as noise or error. From this perspective, it is apparent that variability in movement systems is omnipresent and unavoidable due to the distinct constraints that shape each individual’s behaviour. In this position paper, it is argued that trial-to-trial movement variations within individuals and performance differences observed between individuals may be best interpreted as attempts to exploit the variability that is inherent within and between biological systems. That is, variability in movement systems helps individuals adapt to the unique constraints (personal, task and environmental) impinging on them across different timescales. We examine the implications of these ideas for sports medicine, by: (i) focusing on intra-individual variability in postural control to exemplify within-individual real-time adaptations to changing informational constraints in the performance environment; and (ii) interpreting recent evidence on the role of the angiotensin-converting enzyme gene as a genetic (developmental) constraint on individual differences in physical performance.The implementation of a dynamical systems theoretical interpretation of variability in movement systems signals a need to re-evaluate the ubiquitous influence of the traditional ‘medical model’ in interpreting motor behaviour and performance constrained by disease or injury to the movement system. Accordingly, there is a need to develop new tools for providing individualised plots of motor behaviour and performance as a function of key constraints. Coordination profiling is proposed as one such alternative approach for interpreting the variability and stability demonstrated by individuals as they attempt to construct functional, goal-directed patterns of motor behaviour during each unique performance. Finally, the relative contribution of genes and training to between-individual performance variation is highlighted, with the conclusion that dynamical systems theory provides an appropriate multidisciplinary theoretical framework to explain their interaction in supporting physical performance.

The Role of Nonlinear Pedagogy in Physical Education

In physical education, the Teaching Games for Understanding (TGfU) pedagogical strategy has attracted significant attention from theoreticians and educators for allowing the development of game education through a tactic-to-skill approach involving the use of modified games. However, some have proposed that as an educational framework, it lacks adequate theoretical grounding from a motor learning perspective to empirically augment its perceived effectiveness. The authors examine the literature base providing the theoretical underpinning for TGfU and explore the potential of a nonlinear pedagogical framework, based on dynamical systems theory, as a suitable explanation for TGfU’s effectiveness in physical education. Nonlinear pedagogy involves manipulating key task constraints on learners to facilitate the emergence of functional movement patterns and decision-making behaviors. The authors explain how interpreting motor learning processes from a nonlinear pedagogical framework can underpin the educational principles of TGfU and provide a theoretical rationale for guiding the implementation of learning progressions in physical education.

Information-governing dynamics of attacker–defender interactions in youth rugby union

Abstract Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker–defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker–defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m · s−1, a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker–defender dyads in rugby union over time as spatial proximity to the try line increased.

Movement Models from Sports Provide Representative Task Constraints for Studying Adaptive Behavior in Human Movement Systems

Researchers studying adaptive behavior in human movement systems have traditionally employed simplified, laboratory-based movement models in an effort to conserve experimental rigor. Brunswikian psychology raises questions over the representativeness of many of these popular experimental models for studying how movements are coordinated with events, objects, and surfaces of dynamic environments. In this article we argue that sports provide rich ecological constraints for representative task design in modeling the complex interactions of human performers with their environments. Adopting a functionalist perspective enriched by ideas from ecological psychology and nonlinear dynamics, we consider data from exemplar movement models in basketball and boxing to support this contention. We show that this preference for movement models from sports, although not completely novel, has accelerated over recent years, mainly due to the theoretical re-emphasis on studying the interaction of individual and task constraints. The implications of using such applied models of move ment behavior in studying the design of natural and artificial systems are also discussed.

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 symmetrybreaking 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.

Interpersonal Pattern Dynamics and Adaptive Behavior in Multiagent Neurobiological Systems: Conceptual Model and Data

ABSTRACT Ecological dynamics characterizes adaptive behavior as an emergent, self-organizing property of interpersonal interactions in complex social systems. The authors conceptualize and investigate constraints on dynamics of decisions and actions in the multiagent system of team sports. They studied coadaptive interpersonal dynamics in rugby union to model potential control parameter and collective variable relations in attacker–defender dyads. A videogrammetry analysis revealed how some agents generated fluctuations by adapting displacement velocity to create phase transitions and destabilize dyadic subsystems near the try line. Agent interpersonal dynamics exhibited characteristics of chaotic attractors and informational constraints of rugby union boxed dyadic systems into a low dimensional attractor. Data suggests that decisions and actions of agents in sports teams may be characterized as emergent, self-organizing properties, governed by laws of dynamical systems at the ecological scale. Further research needs to generalize this conceptual model of adaptive behavior in performance to other multiagent populations.

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.

How small-sided and conditioned games enhance acquisition of movement and decision-making skills

This article summarizes research from an ecological dynamics program of work on team sports exemplifying how small-sided and conditioned games (SSCG) can enhance skill acquisition and decision-making processes during training. The data highlighted show how constraints of different SSCG can facilitate emergence of continuous interpersonal coordination tendencies during practice to benefit team game players.

Sports Teams as Superorganisms

Significant criticisms have emerged on the way that collective behaviours in team sports have been traditionally evaluated. A major recommendation has been for future research and practice to focus on the interpersonal relationships developed between team players during performance. Most research has typically investigated team game performance in subunits (attack or defence), rather than considering the interactions of performers within the whole team. In this paper, we offer the view that team performance analysis could benefit from the adoption of biological models used to explain how repeated interactions between grouping individuals scale to emergent social collective behaviours. We highlight the advantages of conceptualizing sports teams as functional integrated ‘super-organisms’ and discuss innovative measurement tools, which might be used to capture the superorganismic properties of sports teams. These tools are suitable for revealing the idiosyncratic collective behaviours underlying the cooperative and competitive tendencies of different sports teams, particularly their coordination of labour and the most frequent channels of communication and patterns of interaction between team players. The principles and tools presented here can serve as the basis for novel approaches and applications of performance analysis devoted to understanding sports teams as cohesive, functioning, high-order organisms exhibiting their own peculiar behavioural patterns.

Interpersonal Distance Regulates Functional Grouping Tendencies of Agents in Team Sports

Abstract The authors examined whether, similar to collective agent behaviors in complex, biological systems (e.g., schools of fish and colonies of ants), performers in team sports displayed functional coordination tendencies, based on local interaction rules during performance. To investigate this issue, they used videogrammetry and digitizing procedures to observe interpersonal interactions in common 4 versus 2 + 2 subphases of the team sport of rugby union, involving 16 participants aged between 16 and 17 years of age. They observed pattern-forming dynamics in attacking subunits (n = 4 players) attempting to penetrate 2 defensive lines (n = 2 players in each). Data showed that within each attacking subunit, the 4 players displayed emergent functional grouping tendencies that differed between the 2 defensive lines. Results confirmed that grouping tendencies in attacking subunits of team games are sensitive to different task constraints, such as relative positioning to nearest defenders. It was concluded that running correlations were particularly useful for measuring the level of interpersonal coordination in functional grouping tendencies within attacking subunits.