A Biomechanical Comparison of the Multisegment and Single Unit Topspin Forehand Drives in Tennis

Three-dimensional (3-D) high-speed photography was used to compare different forehand techniques of high performance players. Subjects, who hit a topspin forehand drive with the hitting limb moving almost as a single unit (Gs: single-unit group), were compared with players whose individual segments of the upper limb moved relative to each other (Gm: multisegment group) when playing the same stroke. The Direct Linear Transformation method was used for 3-D space reconstruction from 2-D images recorded from laterally placed phase-locked cameras operating at 200 fps. A third Photosonics camera operating at 100 fps filmed from overhead. Significant differences between the groups were recorded at the shoulder and elbow joints at the completion of the backswing. Maximal elbow joint angular velocities occurred 0.06 sec prior to impact, with the Gm group recording a significantly higher mean value for elbow extension than the Gs group. At impact, however, the Gm group recorded a significantly higher level of elbow flexion than the Gs group and achieved a higher mean angular velocity at the wrist joint than the Gs group. The Gm group recorded a higher racket tip linear velocity at impact and higher postimpact ball velocity when compared to the Gs group. The Gm technique of racket movement produced higher racket and ball velocities for this group of high performance players.