Ground Reaction Force differences on fastballs vs change ups in pro hitters

This study measured difference in GRF on pro batters (AA level) while throwing fastballs and change ups during batting practice.

Main takeaways:

• Batters took same load/timing on each type of pitch - back foot GRF magnitudes were the same
• Peak back foot GRF happened near timing of pitch release
• Main differences were in the GRF of the front foot
• Peak GRF on the fastball happened closer to contact
• Front foot commitment (50% vertical GRF) happened 29 milliseconds (.029s) later for successful change-up contact and 41 milliseconds (.041s) later for unsuccessful change-up contact

Summary:

The study analyzed the ground reaction forces (GRFs) in the baseball swing and compared them among swings against fastballs and changeups. The focus was on the weight shift of the batter and its impact on the timing and balance of the swing. The study found that while the loading mechanism and initial weight transfer were similar regardless of pitch type, the peak front foot GRFs occurred at significantly different magnitudes and times depending on the pitch type and hit result. Successful swings against fastballs had greater peak front foot GRFs compared to successful and unsuccessful swings against changeups. Unsuccessful swings against changeups occurred earlier in terms of timing compared to successful swings against changeups and fastballs. The study aimed to provide insights into how a changeup can disrupt the coordination of a hitter's weight shift.

Link to abstract

Fortenbaugh, D., Fleisig, G., Onar-Thomas, A., & Asfour, S. (2011). The effect of pitch type on ground reaction forces in the baseball swing. Sports biomechanics, 10(4), 270-279.