(72) LONGITUDINAL RELATIONSHIP BETWEEN COUNTERMOVEMENT JUMP FORCE-TIME CHARACTERISTICS AND PITCH VELOCITY IN DIVISION 1 SOFTBALL PITCHERS

Purpose: To examine the longitudinal relationship between countermovement jump (CMJ) force-time characteristics and the velocity of different pitches in collegiate softball players. Methods: 5 female NCAA Division 1 softball pitchers (age: 20.0 ± 1.4 years, height: 175.3 ± 5.6 cm, body mass: 80.4 ± 11.6 kg) completed weekly CMJ testing and speed training pitching sessions over the course of 5 months spanning from the offseason into the preseason. Bilateral CMJ testing was performed on dual force plates, with each subject performing three maximum effort trials with their hands placed on their hips. The force-time data collected from the force plates were used to calculate jump height (JH), time to takeoff (TTT), and relative net propulsion mean force (PMF). The average performances across trials were used for statistical analysis. During the speed training pitching sessions, each pitcher threw 25 maximum effort, full windmill pitches off an indoor, dirt pitching mound that included a combination of fastballs and curveballs. JH, TTT, and PMF were used for a correlational analysis with the velocities of each pitch type. Pearson correlation coefficients (r) and coefficients of determination (R2) were used to examine the longitudinal relationship between CMJ force-time characteristics and maximum pitch velocity during offseason to preseason training. All correlational analyses were completed using RStudio and the criteria for statistical significance was p ≤ 0.05. Results: The performances of the pitchers over 5 months included: JH = 0.28 ± 0.05 m, TTT = 0.76 ± 0.08 s, PMF = 7.9 ± 1.0 N/kg, fastball speed = 58.7 ± 2.4 mph, and curveball speed = 57.6 ± 2.7 mph. The relationships between CMJ force-time characteristics and maximum pitch velocity are visible in Figure 1. The relationship between pitch velocity and TTT was statistically significant (p < 0.001); however, the relationships with JH (p = 0.323) and PMF (p = 0.232) were not. JH, TTT, and PMF explained 0.05%, 2.20%, and 0.07% of fastball and curveball speed variance, respectively. Conclusions: Despite a statistically significant correlation to pitch velocity, TTT only explained a small portion of the variance in pitch velocity. JH and PMF did not show significant or meaningful relationships with pitch velocity. Practical Applications: It is important that practitioners identify the ability of different testing variables to explain different sport-specific performances to improve athlete monitoring protocols. CMJ height, TTT, and PMF do not appear to be effective performance metrics that may be used to monitor the technical skill of softball windmill pitching and thus, further research is necessary. Acknowledgements: None