Jonathon Headrick, Keith Davids, Ian Renshaw, Duarte Araújo, Pedro Passos, and Orlando Fernandes

The Big Idea

The time and path of a major storm ravaging parts of Europe can be influenced by the flapping wings of a butterfly in the Amazonian jungle (“the butterfly effect”).  So too can small changes in the sub-phases of a non-linear dynamic system of a football game have big later-consequences on the outcome of the game.  In other words, small causes may have larger, later effects.

In this research paper, we have an example of the significance of studying the sub-phases of team sports.  There is consensus in the research community that the actions and interactions of most team sports are complex, dynamical systems.  Localised interpersonal interactions within the game-as-a-whole—which constitute the entire make-up of the play—can indeed influence a match on a macroscopic scale.  The better we understand the nature and significance of the sub-phases of association football, the more relevant and productive our training and practice sessions will become.


  • Emergent decision-making by players in the throes of competition become the football version of butterflies flapping their wings.
  • Most important is for players to know where they are on the pitch and what sub-phase of the game is in play.
  • The aim of this study was to determine whether space and time interactions between footballers in 1 vs. 1 sub-phases are influenced by their proximity to the goal.
  • Three field positions were designated: (a) attacking the goal; (b) in midfield; and (c) advancing away from the goal.
  • The interactions of the attacker-defender dyads were filmed and digitised.
  • There were significant differences between defender-to-ball distance between locations (a) and (c), at the moment when defender-to-ball had stabilised.
  • The findings indicated that proximity-to-goal does influence player performance, especially when attacking or advancing away from the goal areas.
  • These results have implications for practice and training design, namely that it is best to simulate sub-phase constraints rather than through generalised non-contextual cones and poles.
  • Practicing sub-phases also invites players to explore affordances (opportunities), allowing for emerging decisions in competition thereby reducing reliance on carrying out pre-conceived task instructions.

The Research

This study focuses on what are called attacker-defender dyadic systems.  This means the focus is on the manner of play between a player in possession of the ball—a defender—and the context of the task dyad: a target or goal.  These interactions create and reveal the players’ decision-making process.  In the process of what is called ecological dynamics, it is the very presence of the environmental constraints that make relevant individual player decisions.

The typical restraints are classified in three ways.   First, there are the constraints the players themselves bring to the contest, such as personal physical and psychological features.  Second, there are environmental constraints, both physical variables (temperature, light, condition of the pitch), and social variables (norms, cultural factors).  Third, task constraints are rules, equipment, field dimensions and markings.

While various approaches have been taken in investigating attacking-defending sub-phases in such sports as basketball and rugby union, football is a trickier undertaking because of the unique task of trying to control the ball on the ground with the feet.  In this study design, the researchers wanted to know more about how each player in a dyad interacts with the ball in different locations of the field.  This information could expose how player intentions and play affordances (opportunities) are constrained by the risk/benefits of various performance situations.  If, through this kind of research, we can learn more about emerging patterns of behaviour without having to rely on specific task instructions (from a coach, for example), then training sessions can be designed for players to themselves perceive critical distances between each other and the ball that influence intentionality and decision-making behaviours.


The researchers wanted to learn in an experiment whether football players’ decision-making behaviour could be influenced by manipulating proximity-to-goal of the players in 1 vs. 1 dyads.  They predicted that attacker-defender dyads existing closer to either the attacking or defensive goal of the ball dribbler would reveal different strategies and distinct player-to-ball distance patterns than trials in a midfield position due to the constraint on performance imposed by the value of these goal areas.

The study included twelve male participants (roughly 15 years of age), all of whom were members of the Queensland Academy of Sport U-19 state football development squad.  They reported a mean of 10 years of formal football experience and training.  Both right and left footers were included, as well as representing all positions except goalkeepers.

Each participant performed the role of a ball dribbler (attacker) and defender at three field locations against two different single opponents.  There were twelve 1 vs. 1 trials.  Each attacker-defender dyad competed in an area 10 m (length) X 5 m (width), and representing the three locations: a) attacking the goal (defender on edge of penalty area directly in front of goal, dribbler 10 m further from goal); b) midfield (the two players were positioned 5 m either side of the half-way line within the centre circle, representing a defensive midfielder versus a lone dribbler); and c) advancing away from goal (dribbler began on edge of his own penalty area while defender began 10 m further from goal; player in possession represented lone defender in front of his own goal versus a single opposing player).

The tests were based on the dribbler aiming to move through the performance area, and passing the defender.  Success meant that the dyad was destabilised.  The defender, in contrast, aimed to maintain dyad stability by preventing the dribbler from advancing the ball.  Only general information was given to the participants about the task goals, no task instructions.  The trials were filmed with a digital video camera.  The video footage was transferred to a computer for digitising the data for analysis.


Remember that the study aim was designed to learn whether proximity-to-goal acts as a constraint on the relationship between players and the ball in attacker-defender dyads in association football.

The results of the study found statistically significant effects of player-ball relations; also, representative plots of player-to-ball distance patterns were found for different field positions.

The trials in location (a) were on average found to stabilise at a moment of constant distance-to-ball (D-ball) distance at a greater D-ball distance than trials in position (c).  This finding of constant periodicity in (a) can be a critical region “where the players have been drawn together and their actions have become coordinated.”

This means that the dyad at this point could remain stable or become destabilised by way of interactions between the performers.

The percentage of successful trials for the dribbler in each field position also showed higher success rates for (a) and (c), both of which were closer to goals than was (b).

It was also the case that the intentionality of both players in location (a) were conservative.  The defender couldn’t be risky since he was the last remaining player between him and the goal.  Likewise, the attacker could be conservative by waiting a bit to find the right moment to move in position for a shot on goal.  But in position (c), the period of constant D-ball distance was brief.  The lone dribbler would be motivated to move the ball away from his goal as quickly as possible.  The lone forward playing as a defender could attempt to take the ball at any time and at little risk given the distance away from the defended goal.

In summary, here is what the study showed:

  • The midfield trials (b), equidistant from both attacking and defending goals returned the lowest success rates for dribblers and hence does not provide strong contextual information for the performers.
  • But proximity to the goal does indeed provide a source of constraint on the intentionality of players in 1 vs. 1 dyads.
  • Intentionality and emergent player behaviour differed depending on their distance to key reference points (goal, penalty area.
  • Such differences reflect the importance of understanding the player-environment relationship.

Implications for practice designs

There are several suggestions these researchers have for the design of football practice sessions.

  • It is essential that in practice designs it is essential to know exactly what sub-phase or situation is being simulated.
  • It is also imperative to know whether appropriate environmental information is available to replicate the selected performance context.
  • It is best for learning designs to position practice/tasks to be properly constrained by relevant field positions; best not to employ generalised practice/tasks that are absent scenario-specific information. In other words, the use of specific reference objects like corner flags, goals, and line markings are always better than ambiguous poles or cones posted without any reference to areas of the field or situations/context.
  • Especially helpful insofar as player development is concerned is to encourage players to explore environmental information themselves, rather than always providing preconceived task instructions.
  • Players who are encouraged to make decisions for themselves will produce practice activities in sync with the competitive performance environment.

Float like a butterfly,Sting like a bee–Muhammad Ali

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