JOINT FORCES AND TORQUES OF THE UPPER EXTREMITY DURING STANDING SMASH AND JUMPING SMASH IN SOFT-TENNIS

Abstract

Both standing smash (SS) and jumping smash (JS) use the overhand swing, but are under different conditions from the viewpoint of external force. These two trials were filmed by two synchronized high-speed cameras (250Hz) and 3-D data were obtained using the direct linear transformation procedure. As kinematical data, linear resultant velocity of the racket head and absolute joint angles of upper extremity did not show any significant difference; as for kinetical analysis, joint forces and torques of upper extremity were calculated anatomically. There were no apparent differences in general temporal variations. However, about the shoulder adduction and horizontal adduction torques near initiation of forward swing (IFS), torque peaks of the JS appeared later than that of the SS. Additionally, elbow anterior force of the JS was larger than that of the SS.