| Abstrakt: |
Problem Statement: Many studies have examined changes in pitching speed and limitations in the number of pitches during repeated pitching motions by subjects with baseball experience. However, findings during repeated pitching by subjects with little baseball experience have not been reported. Purpose: This study aimed to clarify the transition of the speed and the spin rate of a ball thrown repeatedly by an unskilled subject. Materials and Methods: A healthy male subject threw a ball repeatedly for a total of 100 throws (5 sets at 20 balls/set), and changes in ball speed and spin rate were examined. Ball speed and spin rate were calculated by digitizing eight analysis points on the ball for five frames after ball release. Results and Discussion: Results showed that ball speed was significantly lower in the second set than the first set. However, the ball spin rate did not change during the repetitive throwing. When the relative speed to the maximum ball speed was compared with that of baseball players, it was found that not only did the ball speed decrease earlier than that of baseball pitchers during repetitive pitching, but it did not stabilize even during the first set when the effect of fatigue was less. When the coefficient of variation of ball speed within a set was compared with that of male baseball players from adolescents to adults, unskilled players showed the same degree of stability as the adolescent boys, suggesting that training experience may contribute to ball speed stability. When the relationship between ball speed and spin rate was compared with that of baseball players, it became clear that unskilled players had less ball spin to ball speed, suggesting the need to compare pitching motions, including finger movements. Conclusions: These results suggest that it is crucial for unskilled players to throw fewer pitches than experienced players during games and to receive training in order to achieve a high pitching speed. [ABSTRACT FROM AUTHOR] |
