Relationship Between Bat Mass Properties and Bat Velocity

Fleisig GS, Zheng N, Stodden DF, Andrews JR. Relationship between bat mass properties and bat mass velocity. Sports Engineering 5(1):1-8, 2002.

Methods

17 male collegiate baseball players and 17 female collegiate softball players were studied swinging aluminum bats, some of which were altered to create different moments of inertia (MOI). The swings were recorded by a high speed (200 frames per second) three-dimensional motion analysis system and digitized. The digitized data was analyzed to determine angular velocity of the bat and linear velocity of the bat’s “sweet spot” for the last two frames before ball impact.

Results

Analysis of the data revealed significant differences in linear velocity among the various bats for both baseball (24.7-26.8 m/s) and softball (19.4-22.2m/s). Differences in angular velocity were not significant for either baseball (2080 m/s) or softball (1740-1890 m/s). Further, a linear correlation was found between linear velocity and bat MOI. No such correlation was found for bat mass.

These findings suggest that baseball organizations wishing to limit bat velocity should consider regulating MOI rather than bat mass. However, the complex nature of the concept of MOI may not be easily understandable for league officials and coaches. Measuring MOI may also be impractical for such organizations. It may be more practical to regulate bat mass and location of the center of gravity.