2014 Volume 59 Issue 2 Pages 771-788
The purpose of this research was to clarify the technical characteristics of the swinging motion performed by female players by comparing their instep kicking movements with those of male soccer players, as well as to consider technical factors by which female players can increase the ball velocity. Twenty-six participants (13 female and 13 male players) were requested to perform instep kicks with maximum effort, and their kicking movements and corresponding ground reaction forces were captured using a three-dimensional motion capturing system (250 Hz) and force plate (1000 Hz), respectively.
The knee joint and hip joint torques during the forward swinging phase were lower for female players than for male players; this is considered to be a factor explaining the lower foot velocities for female players in comparison with male players.
Furthermore, the thigh-to-shank energy ratios for female players were significantly lower than those for male players. This suggested that with regard to the forward swinging phase, the technique employed by female players for the kinematic chain of movements related to transmitting energy from the thigh to the shank had less potential than the technique used by male players. This led us to conclude that female players can increase their foot velocities by improving their movement chain technique, which can result in increased ball velocity.
Moreover, a forward dynamics simulation using the vertical component of the force at the hip joint as input was performed to consider the effects of the vertical force of the hip joint on swinging velocity. An investigation of the effects of the vertical force of the hip joint on swinging velocity indicated that the latter tended to increase as the vertical force increased. From this we concluded that accelerating the hip joint of the kicking leg in the vertical direction increased the swinging velocity during the instep kicking movements performed by female players. This is considered to be one of the technical factors that can be used by female players to increase the ball velocity.