Foot dominance and ball approach angle affect whole-body instep kick kinematics in soccer players.

Past investigations provided limited information regarding instep kicking kinematics in soccer. It is unclear how foot dominance and ball approach angle impact whole-body kinematics and consequently the ball velocity. We aimed to analyse the effects of the ball approach angle and the foot used on the whole-body kinematics of soccer players performing an instep kick. Twenty-four soccer players performed maximal instep kicks, using the dominant and non-dominant feet, with the ball stationary or rolling from four different directions. Whole-body motion was recorded during the kicking action and kinematic time-series were extracted and resampled to 200 points equally divided into kicking and follow-through phases. 1-D statistical parametric mapping two-way ANOVA tested for the effect of ball condition and foot dominance. Ball approach angle affected most of the swinging and support limb variables and some upper body variables. Performance-related variables such as CoM, foot, and shank velocities were reduced when the ball approached posteriorly. The linear and angular velocities of the swinging limb, and CoM vertical position, were higher when kicking with dominant foot. Based on these findings, as a practical implication, coaches should vary ball approach angles and the foot used during kicking drills to improve technical effectiveness in various situations.