Comparing Intra-Limb Coordination and Timing of Performing a Baseball-Pitch in Skilled and Unskilled Pitchers with Emphasis on Different Movement Phases

The coordination of body limbs and the timing during performing of a Baseball-pitch and its different movement phases are relatively unknown. The purpose of the present study was to describe and compare the coordination between the shoulder-elbow joints and timing during execution of a Baseball-pitch by skilled and unskilled subjects emphasizing movement phases. The subjects consisted of a skilled male pitcher and eight beginner pitchers. Intra-limb coordination was obtained for the shoulder-elbow joints and was shown by angle-angle plots. Start and end points of all pitchers were normalized by linear interpolation method to 250 points. Timing, angles of the beginning and end of each phase, and the minimum and maximum angles of shoulder and elbow joints in each phase were compared between skilled and unskilled pitchers. The results indicated that there is a relatively clear difference in the coordination patterns between the joints of the shoulder-elbow, especially in the first and second phases between skilled and unskilled pitchers. There were also many differences between unskilled pitchers with the skilled pitcher at the beginning and end as well as the minimum and maximum angles of shoulder and elbow joints in different phases. Considering the timing variable, the time of performing the whole movement and the first, fourth, and fifth phases in unskilled pitchers was significantly shorter than that of the skilled pitcher. The results were discussed with regard to spatiotemporal characteristics of the performing Baseball-pitch in skilled and unskilled pitchers. Also, were discussed practical considerations for improving skills and preventing injury.