Active success drives momentum, but late-stage errors destroy it: a real-time analysis of volleyball.

INTRODUCTION: Psychological momentum is a dynamic system that characterizes the psychological states of individuals progressing toward or regressing from goal attainment. As research has largely relied on controlled laboratory settings or artificial scenarios, empirical evidence from actual athletic competitions remains limited. Therefore, this study aimed to comprehensively elucidate how play content, game stages, and player expertise interact to dictate the micro-dynamics of momentum among actors during a real match.

METHODS: Real-time measurements were conducted with 25 male high-school volleyball players during practice matches to ensure high ecological validity. Participants used voice recorders during natural intervals between rallies to verbally rate their momentum fluctuations. A dataset comprising 2,103 observations was analyzed using a linear mixed model to evaluate the fixed effects of expertise, game stage, play content (active success versus opponent error), and rally outcomes. Because the model did not include the lagged dependent variable, the first-order autoregressive [AR(1)] residual covariance structure was used only to address potential serial correlation in the residuals across adjacent rallies, rather than to model temporal carryover in psychological momentum itself.

RESULTS: Scoring through a team's active success yielded significantly higher momentum improvements than scoring through an opponent's error across all game stages. In the late stages of a set, conceding a point because of a self-induced error resulted in a significantly more severe deterioration of momentum than conceding a point through an opponent's active success. Furthermore, advanced players exhibited a significantly greater decrease in momentum following lost points than intermediate players.

DISCUSSION: These findings suggest that momentum fluctuations are highly sensitive to players' internal attributions of events, particularly the high mutability and regret associated with late-stage errors. Advanced players' acute sensitivity to conceded points highlights the phenomenon of proxy agency and the risk of proxy dilemmas among less experienced teammates. Practically, coaches can mitigate this overreliance and enhance self-agency by assigning specific, specialized roles, such as defensive pillars or high-set providers, to every player, ensuring that all participants can exercise personal agency and earn mutual trust within the team.