| 摘要: | Baseball pitching is one of the most dynamic throws in various pitches. Fastball, curveball, and slider were the kinds of pitches need to learn more to mastering technique and skill in baseball game. Kinematic and kinetic parameters were more important to improve performance and prevent from injuries. The purpose of this study was to evaluate the differences among fastball, curveball and slider in biomechanics. (1) Differences in the torque at the shoulder and elbow among fastball, curveball, and slider. (2) Differences on the forearm motion among fastball, curveball, and slider. (3) Differences the angular velocity at the shoulder external rotation among fastball, curveball, and slider. (4) Differences the angular velocity in the elbow angular velocity among fastball, curveball, and slider. (5) Differences the elbow extension at arm deceleration among fastball, curveball, and slider, and (6) Differences among fastball, curveball, and slider at ground reaction force. Twenty-Four male collegiate baseball pitchers volunteered to participate in this study. Each participant performed 3 sets of pitches; 5 Fastball, 5 Curveball, and 5 Slider with maximal efforts. Eleven Eagle cameras with a sampling rate of 250 Hz and a shutter speed of 1000 Hz. One force plate by AMTI was exerted to measured ground reaction force at 1200Hz. Stalker Radar Gun Sport Serie 2 was used to measure the maximal speed with 10-millisecond speed with range 300 feet. Repeated measurement ANOVA and post hoc test was used to test the effects of pitching phases among fastball, curveball, and slider. In all, 16 of 29 variables were found to be significantly different among fastball, curveball, and slider in kinematics data. 1 of 19 kinetics variable was significant difference. Kinematic parameter at shoulder has higher value at fastball than other pitch, but curveball consistently greater in the elbow activity. Another result was found in elbow extension at foot contact, significant difference showed that curveball was higher than slider and fastball. Forearm was more supinated in arm cocking and arm acceleration phases for fastball. For slider, the intensity of pitching was lower compared to fastball and curveball. The characteristic of ball rotation between fastball and curveball were caused by the similar swing motion of the throwing arm. Differences in the wrist and forearm motions between pitch types, stride length, velocity, and force contribution of specific elbow ligament, tendon, and other structures were the cause of differences in the pitchers. To prevent injuries and maintain performance, a varus torque must be applied to the forearm at the elbow. Pitcher generated greater elbow varus torque and elbow extension velocity when perform pitching and the motions implied a greater risk for valgus extension overload. Greater elbow torque oriented more stressful for pitcher to get injury. But lower values in the parameters have a meaning that intensity can generate power more effectively to decrease injury level when release the ball. Joint kinetic increased with the level of competition, a higher level in pitcher has more susceptible to the arm injury. Pitchers with higher level have a greater risk of injury, since they showed greater anterior force, proximal force, and internal rotation velocity. Shoulder and elbow are the most often to get injuries when pitcher perform. The muscles of the rotator cuff produce the majority of the rotation movement of the shoulder during throwing as well as provide dynamic stability to the shoulder joint. Greater parameter in pitcher’s performance can be the one of factor can increase performance. But, the greater parameter in kinematic and kinetic also can be the main cause of injuries. Injury prevention and pitching performance enhancement are the main concepts for pitcher to get their best performance. Proper pitching mechanics are the key of success of the baseball pitcher. Poor mechanics can lead the increased injury risk. As we know, each pitcher is a different person and they have their own pitching style. Kinematics and kinetics differences among pitch type are important not only for injury prevention, but also for performance elevation. Strong fundamental is an important key to success for baseball pitcher to get to the next level. Pitcher also need to practice good form and attempt to duplicate the proper pitching mechanics for each and every pitch. Coach will monitor every form and pitching mechanics for any problems. The earlier a problem or inconstancy was identified then the quicker it can be remedied. This information can be used as guidelines to the coaches and pitchers to improve performance and injury prevention. |
