Comparison of kinematic and temporal parameters between different pitch velocity groups

This study investigated differences in kinematic and temporal parameters be tween two velocity groups of baseball pitchers. Data were collected from 12 7 healthy college and professional baseball pitchers. Those who threw faste r than 1 SD above the sample mean (>38.0 m/s) were assigned to the high vel ocity group (n = 29), and those who threw slower than 1 SD below the sample mean (<34.2 m/s) were assigned to the low velocity group (n = 23). Twelve kinematic parameters and 9 temporal parameters were measured and analyzed. The pattern of lead knee movement was also investigated. Maximum shoulder e xternal rotation, forward trunk tilt at the instant of ball release, and le ad knee extension angular velocity at the instant of ball release were sign ificantly greater in the high velocity group. Maximum lead knee flexion ang ular velocity was significantly greater in the low velocity group. Seventy percent of the high velocity group showed knee extension during the approac h to ball release, whereas the low velocity group showed a variety of knee movement patterns involving less knee extension and more knee flexion. The greater shoulder external rotation in the high velocity group produced an i ncreased range of motion during the acceleration phase.