Kinematic comparisons of kick directions during the instep soccer penalty kick
The purpose of the study was to compare the differences in the kinematics of the instep kick movement in different kick directions in a soccer penalty kick. The significant aspects of the joint movements that influence the kick directions were determined. Eleven female soccer athletes performed the instep kick in two different directions (left and right posts) on an outdoor field. The kinematic data measured from kick techniques were collected using three standard video cameras and a high speed camera (80Hz). All the data was analyzed by paired t-test. There are several variables that are significantly different between the two kick directions. There are only three variables that can predict kick direction significantly: support foot orientation, distance from support heel to the ball center and approach angle. The support foot may be the most useful cue for goalkeepers to predict the ball direction. Other cues may be less helpful because they are difficult to interpret or too subtle to be detected.