Perception-action coupling for goalkeeping in football: the free kick scenario

Abstract

Free kicks near the penalty box area can be a good scoring opportunity. The ball's visibility, the complexity of the environment and the limited time to act against a well-shot free kick may be reasons why goalkeepers struggle. This thesis investigates how these visuomotor factors influence a goalkeeper’s behaviour in a variety of free kick scenarios. The introductory chapter covers topics related to interceptive tasks in sports, and the factors that influence the coupling between perception and action during the interceptive actions expert goalkeepers make to stop free kicks. This contributes both to the fundamental understanding of perception-action coupling as well as its practical applications in football. Chapter 2 focus on the effect of the wall on goalkeeper’s performance, examining this for both novices and expert participants and for a large range of free kick trajectories. Chapter 3 presents a direct comparison in the behavioural effects of equivalent amounts of sidespin, topspin, and backspin. This chapter also examines such free kicks that curving into the goal near the edges of the goal. Chapter 4 explores the behavioural effects on goalkeepers when stopping free kicks, again with all types of spin, of the ball’s print pattern (which influences the perception of ball-spin). The final chapter discusses the overall findings presented in this thesis in the context of current and potential future research on interception and goalkeeping, and reviews and practical implications that may emerge from this thesis. This research is unique also because of the methods employed. With the advent of virtual reality, it is now possible to recreate identical free kick scenarios for each participant and create an immersive interactive experience that mimics the real situation remarkably well. It was possible to acquire scientific data in the lab while giving a realistic experience to the participant.This thesis’s aim was to ‘decipher free kicks in football’, shedding light on the factors influencing interceptive movement behaviours of goalkeepers. This was studied in several free kick scenarios in order to evaluate the use of ball flight information. The thesis showed that removing such information early on, by visually blocking the early ball flight using a wall, can negatively affect performance. It also reported qualitative differences between the effects of spin around different axes, a modulation of the effects of spin by the to-be-defended goal area, and benefits of seeing the ball spinning. These findings lay the groundwork for further investigation of free kicks, both for the goalkeeper and the kicker. It is not unlikely that the better understanding of how goalkeeping intercept free kicks, emerging from this thesis and the future investigations it motivates, can aid goalkeepers as well as free kick takers in practice.

Date of Award	Dec 2023
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	EC/Horizon 2020 Marie Skłodowska-Curie actions
Supervisor	Joost C. Dessing (Supervisor) & Mihalis Doumas (Supervisor)