Assessing and understanding collective behaviour in youth soccer

The study of collective behaviour in soccer is a popular and practical topic of research. The Ecological Dynamics framework has gained prominence in recent years as a way to understand and assess collective behaviour. This thesis aims to further this understanding in the context of youth soccer by building upon the Ecological Dynamics framework through a literature review and three individual studies. The studies will explore different aspects, such as the association between individual and tasks constraints and commonly used measures of collective behaviour, and the validity of coaches' subjective observations of collective behaviour in small-sided games (SSG). The first study analyses the relationship between a priori classifications of playing level and commonly used measures of collective behaviour in soccer SSG. The findings reveal that teams at relatively high- level attempted and completed more passes, touches and shots compared to teams at a lower level, but no associations were found between teams' skill levels and teams' passing networks characteristics or spatiotemporal behaviours. The second study examines the link between task constraints commonly used by coaches, such as manipulating the format of SSG or providing verbal instructions, and the skills and passing networks of teams. The study examines both situations where a single constraint is manipulated and when two constraints are manipulated at the same time, which is more similar to real-world coaching practices. The findings reveal that unconstrained SSG were associated with more dribbling involvements and teams exhibited more well-connected passing networks when provided with verbal coaching instructions. The third study delves into the subjective perception of soccer coaches with varying levels of expertise when observing SSG and compares it to objective measures. The study explores the validity of coaches' subjective observations of complex collective behaviour in SSG and examines the gaze behaviour of coaches while observing the games to gain insight into the perceptual processes that support their observations. The findings reveal no differences in how frequently subjective and objective observations matched or mismatched between coaches with differing levels of experience. Overall, this thesis provides insight into how teams coordinate with each other in the presence of different constraints. While research in this field is still underpowered and inconclusive, this thesis highlights the importance for practitioners to understand the influence of different types of constraints on collective behaviour. We propose that coaches and analysts can utilise passing networks and variables derived from spatiotemporal measures in addition to more traditional notational analyses to enhance their understanding of team performance.