2006 年 22 巻 p. 15-22
There has been no research examining the throw distribution of baseball pitchers. We investigated the throw distributions when a batter was absent and when the standing positions of batters were changed. Subjects were four baseball pitchers. All subjects were right-handed and pitched overhand from the mound to the target. Subjects threw under four conditions, 1) Control (C); a batter was absent, 2) Right Near (RN); a right batter stood near to the target, 3) Right Far (RF); a right batter stood far from the target, 4) Left (L); a left batter stood. The throw distribution was evaluated by the shape of the ellipse of constant distance and coordinates at the throw position. Under condition C, the throw distributions of all subjects were ellipses and their major axes were inclined clockwise (from the pitchers view). These results suggest that the clockwise inclination of the throw distributions were due to the orbits of the right arms' movements of the pitchers. In the condition RN, three subjects threw a ball lower compared to the other conditions and the upper right part of their ellipses which was observed under the other conditions was absent. The results in the condition RN might be due to the psychological conditions of the pitchers that they avoid hitting a batter by a pitch. It is considered that these results would be useful for baseball coaching.