THE EFFECTS OF INCREASED DISTANCE ON BASKETBALL SHOOTING KINEMATICS

Abstract

The aim of the study was to Investigateah8 relationship between shooting distance and the changes in technique employed to achieve the required release parameter values for a successful shot. Three dimensional video techniques (50 Hz) were used to obtain Images of basket ball jump shots from one of 3 distances (short range - Group 1 ; medium range - Group 2; long range - Group 3) from the basket, as performed by members of the men's quarter finalists teams at the games of the XVI Universiade In Sheffield in 1991. Fifteen sequences were digitised, beginning 20 frames prior to take-off to 10 frames post release. To facilitate analysis sequences were rotated about the ball position in the final frame so that the shot direction was parallel to one of the pre-defined orthogonal axes. Mean ball release speed was found to Increase with distance from the basket (Group 1 = 3.04+-0.65 m.s-1, Group 2 = 4.71+-0.74 m.s-1 Group 3 = 6.24+-0.80 m.s-1), the value for Group 1 being significantly (p<.Ol) different from Groups 2 and 3, whilst mean release angles were similar for all groups (Group 1 = 48.8+-10.1°, Group 2 = 47.8+-5.8°, Group 3 = 51 .9+-5.5°). The increased force necessary for the ball to reach the basket at increased shooting distance was derived from both an increase in angular velocity of the elbow joint of the shooting arm at release and an Increased vertical velocity of the centre of mass. Rotation of the hip and shoulder axes, facilitated by the forward placement of the foot on the side of the shooting arm (antero-posterior separation values - Group 1 = 0.09+-0.10 m, Group 2 = 0.18+-0.09 m, Group 3 = 0.06+-0.04 m) allowed alignment of the elbow, wrist and eye. Medio-lateral stability was promoted by separating the feet In the frontal plane. All subjects released the ball whilst airborne. Both the maximum jump height and the height of the jump at release decreased as shooting distance increased. However, release occurred closest to the peak of the jump for the medium range shots (Release to Peak; Group 1 = 0.04+-0.048s, Group 2 = -0.03+-0.087s, Group 3 = -0.084+-0.052s).