Abstract
This study investigated the evaluation of easiness to grasp badminton racket of various diameter, and the movable angle at wrist joint and EMG activity during racket swing motion. The wrist joint movement were palmar-flexion, dorsi- flexion,ulnar- flexion, and radial- flexion. EMG activity was measured for two minutes during ferformed and back swing altemation. The movable angle of palmar-flexion increased as the diameter above the optimum one. In the other movement the tendency was not found in the relationship between grip diameter and movable angle. EMG activity in grasping the optimum diameter of grip was reduction the passage of swing frequency compare with hardness grasping of grip. The decrease in the grip force after endurance swing motion grasping grip with optimum diameter was small.
