BACKGROUND: Approximately 8.2% of all plate appearances in Major League Baseball in 2022 resulted in the batter being walked to first base. Since walks can be detrimental to a pitcher and their team’s success, identifying possible causes is important. This study sought to investigate whether in-game kinematics differed between pitches that resulted in a walk (BB: base on balls), and those that resulted in a strikeout (SO). METHODS: In-game kinematic data were collected on Division I collegiate baseball pitchers using an 8-camera markerless motion capture system (Kinatrax Inc., FL, USA; 300 Hz). Concurrently, ball metric data were recorded for all pitches (TrackMan Baseball, Scottsdale, AZ). A preliminary analysis identified 17 pitchers (1.88 ± 0.04m; 91.7 ± 5.7kg) who threw both a fastball that resulted in a BB, and a SO (not including swinging strikeouts) in the same game. Nineteen kinematic parameters commonly identified in literature, along with vertical and horizontal plate locations, and ball velocity were compared for BBs and SOs using paired-samples t-tests. Where kinematic variables were included for multiple time points, Bonferroni corrections were applied to adjust for multiple comparisons (p = .017). RESULTS: T-tests revealed significantly more shoulder horizontal adduction (arm leading the trunk) at maximal external rotation (MER) (3.7 [± 6.5] vs 1.6 [± 7.4] º; t = 2.689, p = .016), and greater horizontal plate deviation (left of the strike zone) (-0.20 [± 0.31] vs. 0.03 [± 0.23] m; t = 2.391, p = .029) for BBs. Additionally, ball velocity was significantly quicker for SOs (40.9 [± 1.2] vs. 40.7 [± 1.1] m.s-1; t = 3.248, p = .005). CONCLUSIONS: With the exception of horizontal shoulder adduction at MER, kinematics were similar for BBs and SOs. Although variability (standard deviations) was comparable for all variables, the dispersion in plate location was not. The noticeable difference in horizontal strike zone location between BBs and SOs suggests that pitchers may change their intended target when the likelihood of a walk is increased. Though this could be a strategy employed to increase the difficulty of being hit for a run (by throwing the ball away from the batter), it ultimately appears to be detrimental to their performance. Therefore, it may be more beneficial for pitchers to utilize the same target location to increase their chances of throwing a strike.

This document is currently not available here.