Associations between forward center of mass velocity and pitch velocity in NCAA Division I baseball pitchers

In baseball pitching, the pitcher must create linear momentum down the mound, followed by the transfer of linear momentum into angular momentum. Previous research into how the pitcher moves down the mound, towards home plate, has investigated vertical center of mass position, yet forward center of mass velocity has yet to be assessed in its relationship with pitch velocity. Therefore, the purpose of this study is to assess the within- and between-pitcher relationship between maximum center of mass velocity towards home plate and pitch velocity, and to determine if time-series analysis can provide insights into the relationship between center of mass velocity and pitch velocity throughout the entire pitching motion. Data were collected on 332 pitchers (height: 1.88 ± .06 m; mass: 91.6 ± 10.0 kg; 221 right-handed pitchers, 111 left-handed pitchers), during NCAA Division 1 games. Kinematic data were collected using an 8-camera markerless motion capture system (300 Hz). Multi-Level Modeling revealed a weak positive trend between maximum forward center of mass velocity and pitch velocity with high variability between pitchers, suggesting that while a relationship is present, this relationship is not consistent across all pitchers. Statistical Parametric Mapping Regressions revealed significant positive relationships at 0-1 % and 4-7 % of the pitching motion (maximum r = 0.164, minimum p = 0.046), which was from 0.1s before peak knee height(0 %) to ball release (100 %). These results reveal that while there is a small positive relationship between maximum forward center of mass velocity and pitch velocity, it should be assessed on a person-specific basis, while time-series analysis shows that generating COM velocity prior to peak knee height (11.8 %), commonly deemed in applied settings as "body drift", is beneficial to increasing pitch velocity.