Three dimensional (3-D) high-speed photography was used to record the tennis service actions of eight elite tennis players. The direct linear transformation (DLT) method was used for 3-D space reconstruction from 2-D images recorded from laterally placed cameras operating at 200fps. Seven of the eight subjects initially positioned their center of gravity toward the front foot during the stance phase. When the elbow reached 90° in the backswing, the knees of the eight subjects were at or near their maximum attained flexion, and the upper arm was an extension of a line joining both shoulder joints. A mean maximum vertical shoulder velocity of 1.7ms−1during the leg drive produced a force at the shoulder that was eccentric to the racket-limb, thus causing a downward rotation of this limb as measured by a mean velocity of the racket of −5.8ms−1down the back. This leg drive increased the angular displacement of the loop and therefore provided a greater distance over which the racket could be accelerated for impact. All subjects swung the racket up to the ball, and all but one hit the ball with the racket angled slightly backward (M= 93.9°). An effective summation of body segments was apparent because resultant linear velocities showed an increase as the more distal segment endpoint approached impact, although all subjects decelerated the racket immediately prior to impact. Mean resultant ball velocities of 34.4ms−1for the female subjects and 42.4ms−1for the male subjects were achieved.

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.

Three-dimensional (3-D) high-speed cinematographic techniques were used to record topspin and backspin forehand approach shots hit down-the-line by high-performance players. The direct linear transformation (DLT) technique was used in the 3-D space reconstruction from 2-D images recorded via laterally placed phase-locked cameras operating at 200 Hz. A Mann-Whitney U-test was calculated for the different aspects of the topspin and backspin shots to test for significance (P less than 0.05). A significant difference was recorded between topspin and backspin shots in the angle of the racket at the completion of the backswing. The racket was taken 0.48 rad past a line drawn perpendicular to the back fence for topspin trials, but only rotated 0.86 rad from a line parallel to the net in the backspin shot. Maximum racket velocities occurred prior to impact and were significantly higher in topspin (26.5 m s-1) compared to backspin (16.6 m s-1) trials. This resulted in the topspin trials recording a significantly higher ball velocity compared to backspin trials (27.6 m s-1 vs 21.7 m s-1). Pre-impact racket trajectories revealed that in topspin shots the racket moved on an upward path of 0.48 rad while in backspin shots it moved down at an angle of 0.34 rad. In the topspin trials impact occurred significantly further forward of the front foot than in backspin shots (0.26 m vs 0.05 m) while the angle of the racket was the same for both strokes (0.14 rad behind a line parallel to the net). The mean angle of the racket-face at impact was inclined backwards by 0.11 rad for backspin strokes and rotated forward by 0.13 rad for topspin strokes. Angles of incidence and reflection of the impact between the ball and the court showed that backspin trials had larger angles of incidence and reflection than topspin strokes.

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