Influence of ball launch angle and velocity on flight distance in youth elite goalkeepers’ goal kicks

Abstract

This study aimed to clarify how ball launch angle and initial velocity influence flight distance in goal kicks performed by elite youth soccer goalkeepers, and to identify the launch angles associated with maximal distance. Six goalkeepers from the same elite youth team performed maximal-effort place kicks on a stationary ball, simulating goal-kick conditions. The three-dimensional ball motion was recorded using an optical motion capture system (500 Hz), and launch angle and initial velocity were calculated. For each participant, a linear regression model describing the angle–velocity relationship was constructed. Flight distance was then estimated using two-dimensional numerical trajectory simulations under a no-spin assumption.

Across all participants, initial velocity consistently decreased as launch angle increased, although the strength of this relationship and the regression characteristics varied markedly between individuals. Simulations based on measured launch angles and velocities showed that flight distance increased with launch angle within the observed range. When the launch angle range was extrapolated from 5° to 50°, the angle–distance relationship exhibited a quadratic pattern, with maximal flight distances typically occurring at launch angles between approximately 25° and 30°.

These findings indicate that the optimal launch angle for goal kicks is not uniform, but instead depends on each goalkeeper's individual angle–velocity characteristics. This study highlights the importance of individualized, biomechanics-based optimization of launch conditions, rather than relying on a single, standardized angle, for maximizing goal-kick distance in soccer.