Visual regulation of overarm throwing performance.

This investigation examined whether visual feedback is used to make online adjustments during overarm throwing performance. Eight healthy, college-aged males able to throw in excess of 31.3 m/s with previous baseball pitching experience participated. Subjects performed maximal-effort overarm throws under a pretest condition and three test conditions. Under the randomly presented test conditions, the target either maintained its initial location or translated left or right of this location upon stride-foot contact. Subjects were instructed to project the ball to the terminal target location while maintaining maximal speed. Ball landing location, ball speed at release, and several kinematic parameters associated with the throwing motion were compared between conditions. The ball's global landing location within the horizontal dimension in the test-left and test-right conditions was more negative and positive, respectively, than in the pretest and test condition where the target maintained its initial position. Ball speed was lower in all test conditions relative to the pretest condition. Subjects also exhibited less lateral trunk tilt and greater peak pelvis linear velocity in all test conditions relative to the pretest. The overall time from stride-foot contact and ball release was not different between conditions, and no positional kinematic differences were observed between test conditions. The results of this study suggest that visually driven corrections occur late in the throwing motion without changes in the overall movement time. However, there do not appear to be specific features of the throwing motion that all subjects manipulate while making these adjustments.