Kinematic and Kinetic Comparisons between Two Different Strides on Baseball Pitching for Taiwan College Elite Pitchers

This research tried to find out the difference of kinematic and kinetics characteristics for Taiwaness elite pitchers’ pivot legs between different stride types in baseball pitching (tall-and-fall & dip-and-drive). Twenty elite college male baseball pitchers who played in first class college league volunteered to be the subjects in the research. Stalker Sport speed gun , Motion Analysis System, and AMTI force plate were used to measure ball velocity, four kinematic and three kinetic variables. EVa Real-Time software was used to output the trajectory data of each marker and the raw data of force plate during pitching, and Matlab and Excel software were used to filter and analyze data, then participants were assigned to the tall-and-fall group and the dip-and-drive group. All statistical and correlation analysis were performed with SPSS 12.0 software. An independent

t

-test was performed for ball velocity, kinematic and kinetic variables to test the differences between tall-and-fall group and dip-and-drive group. A significance level of .05 was adopted. The result showed that tall-and-fall participants were significantly greater in body height, lower in impulse of ground reaction force during stride phase in pivot leg, and later in the timing of minimum knee flexion angle and maximum ground reaction (normalize with their body weight) than dip-and-drive participants. This research suggested that the timing and value of knee flexion angle and ground reaction force in pivot leg during stride phase were the key difference for techniques between tall-and-fall and dip-and-drive pitchers, and can be used as the reference for improving the pitching performance, injury prevention, and the best option of strides for pitchers.