Abstract
In soccer, the knuckling shot is a kicking technique in which no or slight rotations are applied to the ball, thereby making it move irregularly. However, the technical characteristics of knuckling shots are still unclear, and considerable analysis is required. In this study, we have investigated the swing characteristics of the kicking leg and analyzed the impact process of the kicking foot in order to elucidate the technical characteristics of the knuckling shot. The tendency to impact with the heel pushed out towards the inside of the foot was considered. The angle of attack in the knuckling shot (4°) was smaller than those in the straight and curve shots (20° and 33°, respectively) and was believed to be a factor for balls with smaller rotational frequencies. As a result, in the knuckling shot, reduced angles of attack between the face and swing vectors at impact surfaces and the primarily translational motions at ball impacts are fundamental and important characteristics.
