Abstract：This study was focused to examine the differences of kinematic and kinetic characteristics for elite baseball pitchers' pivot legs between different stride types in pitching (tall-and-fall and dip-and-drive). Twenty elite college male baseball pitchers (age: 20.41±1.60 years, height: 180.00±5.56 cm, weight: 80.37±10.88 kg, maximum ball speed: 38.44±2.04 m/s) were volunteered to be the subjects in the research. Stalker Sport speed gun, Motion Analysis System and AMTI force plate were used to measure the ball velocity, kinematic and kinetic characteristics after an investigation of height, body weight, age, years of playing baseball, years of pitching, maximum ball velocity, medical history and healthy situation. EVa Real-Time Software was used to output the raw data of each marker and the raw data of force plate during pitching. Participants were assigned to the tall-and-fall group and the dip-and-drive group according to this data. All statistical and correlation analyses were performed with SPSS (12.0) software and the significance was set at p＜.05. An independent t-test was performed for ball velocity, kinematic and kinetics characteristic to test the differences between tall-and-fall group and dip-and-drive group. The results showed that tall-and-fall group was significantly greater in body height, lower in the ground reaction force impulse of pitching in pivot leg and later in the timing of minimum knee flexion angle, and maximum ground reaction force than dip-and drive group. This study found that the timing and amount of knee flexion angle and ground reaction force in pivot leg during stride phase were the key differences between tall-and-fall and dip-and-drive groups. Dip-and-drive pitching depended on the press force of pivot leg, and tall-and-fall pitching maybe depended on the muscle strength of trunk and upper limb in pitching. Strength training for those muscles should be emphasized respectively to improve the pitching performance and prevent injury. (Full text)