Sitting on a fastball

Abstract

This is the first study to show that when baseball batters fail to hit change-ups it is because they sit on a fastball. Sitting on a fastball refers to a strategy of baseball batters to always expect a fastball (a fast type of pitch), because expecting slower balls would result in too late movement initiation for unexpected fastballs. Here the authors analyzed movement patterns of highly talented baseball batters facing randomly presented fastballs and change-ups (a slower type of pitch). Results revealed that when batters failed to a hit change-up, this was due to too fast movement initiation patterns that were highly similar to those typically associated with fastballs. More specifically, the movement initiation pattern was not adjusted to the slower speeds of change-ups, resulting in a miss. To the best of the authors' knowledge, this is the first behavioral experiment showing that the strategy of sitting on a fastball exists, and how it affects batting performance on change-ups.

Keywords: baseball; bias; kinematics; movement.