Effect of abduction angle of foot and impact point on ball behavior in side-foot soccer kicking

Abstract

The objective of this study was to investigate the effect of abduction angle of foot and impact point on ball velocity, ball rotation, launch angle, ball deformation and impact force in side-foot soccer kicking.

Five experienced male university soccer players performed side-foot kicks using a one-step approach in varying the attack angle and the impact point. The kicking motions were captured three-dimensionally by two high-speed cameras at 2,500 fps. The attack angle was calculated as the angle between the swing vector that was the velocity vector of the center of mass of the foot and the face vector normal to the medial aspect of the foot. The impact point was calculated as the distance from the center of mass of the foot (projected onto the medial aspect) to the contact point. The effect of the attack angle and the impact point on the ball-foot velocity ratio, ball rotation and launch angle was examined. The impact force was calculated from ball deformation based on the Hertz contact theory.

Impact on the area from the center of mass of the foot to the ankle produced the greatest ball velocity. The ball rotation didn't occur at zero attack angle and increased with an increase in the attack angle. Also, the launch angle increased medially as the impact point approached the heel with large attack angle.