Foot-Ball Impact Effects on Kinematics and Kinetics During Free Kick Execution in Soccer

The paper focuses on the analysis of the biomechanics of the free kick in soccer, including the effects of the ball in the dynamic model. The researchers conducted experiments with two male university football players, capturing their movements using an optoelectronic system. The players performed free-kick shots aiming for the upper left corner of the goal, and the movements were recorded and analyzed. The field characteristics, equipment, and methods used in the study are described in detail. The results show the number of frames in which the foot and ball made contact during each trial, as well as the accuracy of the shots. A 3D biomechanical model was implemented to estimate joint angles, forces, and torques during the airborne phase of the kicking limb. The impact of the ball on the foot and the contact point between them were also determined. The paper provides visual representations and graphs illustrating the observed kinematic variables, dynamic parameters, and joint forces and torques. The average and standard deviation of these variables across all recordings are presented. Overall, the study contributes to the understanding of the biomechanics and motor control involved in free-kick shots in soccer. The findings highlight the importance of measuring the foot-ball interaction for achieving more accurate calculations of joint angles, forces and torques in order to perform more detailed analyses. The research suggests that further exploration of these variables and their relationship to accuracy and performance in football is warranted.