Engineering the Baseball Bat

Terry Bahill
Systems and Industrial Engineering
University of Arizona
Tucson, AZ 85721-0020
terry@sie.arizona.edu
http://www.sie.arizona.edu/sysengr/slides/baseballBat.ppt
Copyright © 2004 Bahill

We will discuss several new scientific discoveries about baseball and softball. (1) There is an ideal bat for each individual baseball and softball player. To determine the ideal bat we must consider (a) the coefficient of restitution of the bat-ball collision, (b) the sweet spot of the bat, (c) the ideal bat weight and (d) the weight distribution of the bat. (2) The coefficient of restitution depends on properties of the ball and the bat. (3) The ball will go the farthest if it hits the bat at the sweet spot. We will demonstrate several definitions of the sweet spot of the bat. (4) Hitting a baseball is the hardest act in all of sports. This act is easier if the right bat is used, but it is difficult to determine the right bat for each individual. Therefore, we developed the Bat ChooserTM to measure the swings of an individual, make a model for that person and compute the Ideal Bat WeightTM for each baseball or softball player. A bat of this weight would make the ball go the fastest after the bat-ball collision. The Ideal Bat Weight is computed by coupling the muscle force-velocity relationship for an individual to the equations for conservation of momentum. (5) For most collegiate batters, outlawing aluminum bats would produce faster batted-ball speeds, thus endangering pitchers. (6) We have created simple models to help select bats for various categories of people: for example for a typical nine or ten year old the Recommended Bat Weight = Height/3 + 4. (7) There is an ideal weight distribution for each batter. All of the university softball players in our study would profit from using an end-loaded bat.

References [43, 50, 75, 86].

This overview was designed for the inquisitive layperson. This talk requires a zip disk drive, PowerPoint and a computer projector. This talk takes one hour.