Abstract des Autors

The kinematics of the trunk and racket at impact in the open stance and the square stance forehand drives were measured with three-dimensional cinematography. Eleven tennis players (6 pros and 5 intermediates) were filmed by 100 Hz as they performed open and square stance forehand drives with a midsized racket. Three-dimensional coordinates of the racket and upper extremity were reconstructed from two cameras using the DLT method. Kinematic data were smoothed with a quintic spline and custom extrapolation procedures to obtain accurate data for the forward stroke at impact. Despite the disparate footwork, there was considerable similarity in the trunk and racket kinematics for open and square stance forehands. Factorial ANOVAs showed no significant effects of stance on racket resultant velocity, vertical path of the racket, and trunk angular velocity at impact. There was evidence of slightly different trunk angular velocity patterns between the open and square stance forehand techniques. Professionals created significantly greater mean racket resultant velocities and trunk angular velocities at impact than intermediate subjects. There is little kinematic evidence of differences between intermediate and professional players in the open stance forehand. Verf.-Referat