| Summary: | 碩士 === 國立成功大學 === 工程科學系碩博士班 === 100 === Introduction：
When the baseball pitchers are learning a new kind of breaking ball, the pitching motion of their shoulders, elbows, wrists and knees need to be adjusted, it is generally known that learning a new breaking ball is a difficult process.
Purpose ：
To study the kinematic and kinetic differences among the fastball, slider and curveball, base on these statistics to build up pitching motion database standard posture.
To study the decreased muscle strength and range of motion of the pitchers after the pitching.
Methods：
Ten professional baseball pitcher. By measuring the range of motion and muscle strength before pitching, after pitching, the first and second days after pitching. Data were collected with an outdoor three dimensional motion analysis system (Raptor-E Cameras, Motion Analysis Corp., Santa Rosa, C.A., U.S.A) which records the progresses of pitchers throwing overhead, pitched fastball, slider and curveball. Statistical methods using repeated measures ANOVA and paired t-test. Significant at P 〈 0.05
Results：
Out of 100 kinematic parameters, 31 kinematic parameters were significantly different between fastball and slider. Out of 33 kinetic parameters, 12 kinetic parameters were significantly different between fastball and slider. Out of 100 kinematic parameters, 66 kinematic parameters were significantly different between fastball and curveball. Out of 33 kinetic parameters, 24 kinetic parameters were significantly different between fastball and curveball. Out of 100 kinematic parameters, 67 kinematic parameters were significantly different between curveball and slider. Out of 33 kinetic parameters, 27 kinetic parameters were significantly different between curveball and slider.
Immediately after pitching, the muscle strength significantly decreased in shoulder flexion((p=0.034), and continued until second day after pitching.
The results of range of motion, show that after pitching, the range of motion significantly decreased in elbow extension(p=0.013) , and continued until second day after pitching.
Conclusion：
Fastball and slider have high similarity in pitching motion, because the velocity of both balls is very fast, so there won't be great difference in pitching motion change, only negligible changes would happen while in the ball release. This ultimately accomplishes the intention of confusing so batters during the game. Curveball is different from fastball and slider in pitching motion, because curveball needs larger trajectory change, and this reflects on the pitching motion. Furthermore, if the batter is able to identify differences, then the moving trajectory of the ball is predictable. While the pitchers throw out a slider and curve ball, it will cause more elbow proximal force and elbow medial force, hence it is suggested that pitchers need to strengthen the elbow muscles, so the occurrence of sports injuries to elbow can be avoided.
The shoulder flexion muscle strength fatigue continued until second day after pitching, the suggestion is to strengthen the shoulder flexion muscle, and avoid sports injuries in the pitching movement.
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