CLINICAL CONSIDERATIONS FOR YOUTH SOCCER HEADING

Abstract

Heading is a unique and essential skill in soccer, and growing concern exists regarding the rate of head injuries among young soccer players. Traditional analysis procedures to estimate head impact forces experienced during soccer heading require subjects to perform multiple potentially harmful head-ball contacts. PURPOSE The purpose of this study was to design a soccer heading simulation model to safely determine the head impact forces and accelerations experienced by children and to examine how these impacts are influenced by ball size, temperature, and pressure. METHODS A soccer heading simulation model was developed using material and inertial properties from head cadaver data and anthropometric measurements. Coefficients of restitution were determined for a set of soccer balls (sizes 3, 4 and 5) under varying conditions of temperature and ball pressure. Male and female youth soccer players (N=32) representing three age groups (under 7, 8 to 11, and 12 to 16 years) were selected for the measurement of soccer ball kicking trajectories and head anthropometry, which served as inputs to the simulation model RESULTS: Coefficients of restitution at 28°C ranged from 0.76 to 0.80, and varied directly with temperature and pressure. Maximum ball velocity exceeded 18.5 m/s. Simulation results determined that ball temperature and pressure were inversely related to head-ball impact force and directly related to head acceleration across ball size. Simulations of the younger age groups heading a maximally kicked size 5 soccer ball (e.g. heading an oversized ball) created impact forces equivalent to over 6 times their body weight and increased head accelerations by 18 to 33%, compared with heading the age-rated ball. CONCLUSION Head-ball contacts during cold weather or with balls traveling in excess of 18 m/s may place youth soccer players at increased risk for neurologic and cognitive effects of head injury. It is important to use appropriate age-rated soccer balls given that potentially unsafe head impact forces and accelerations may occur when younger athletes head larger soccer balls.