Performance of Wood and Non-Wood Baseball Bats.

Principle Investigator: J.J. Trey Crisco, Ph.D., Dept. of Orthopaedics and Engineering

Institution: Brown University and Rhode Island Hospital, Providence, RI

Title: Performance of Wood and Non-Wood Baseball Bats

Background:  The increased performance of modern metal and composite baseball bats has been associated with injuries to field players being struck with the higher velocity batted balls and an imbalance between offense and defense play of the game. Sports governing bodies, from the youth level to the collegiate level, are faced with challenging decisions regarding the legality of these modern bats and what level of bat performance is acceptable and safe. These decisions are made even more difficult by the lack of rigorous scientific data on bat performance. Our previous study (Crisco et al., 2002) has been the definitive work on wood and metal baseball bat performance, and remains the only three-dimensional (3-D) study that has analyzed bat performance with players. The clear limitation of our previous study is that those metal bats are no longer used. Thus, the actual performance of current metal and composite baseball bats is not known. The specific aim of this study is to determine actual bat performance of current metal and composite bats in high school and collegiate players.

Methods: Collegiate (n=20) and high school (n=20) players will be recruited to bat with both wood (3 models) and non-wood (12 models) bat models. The specific models will be chosen in collaboration with the national sports governing bodies. Each player will face 20 pitches with each bat model from a pitching machine. Using the previously established methods (Crisco et al., 2002), the 3-D motion of the pitched and batted ball and the complete 3-D kinematics of the bat will be recorded at 250Hz with an existing motion tracking system (Gothenburg, Sweden). Our novel computer algorithms will compute pitched ball velocity, batted ball velocity, the location of ball-bat impact, bat velocity at the point of impact, rotational velocity of the bat, helical rotation axis of the bat, and instantaneous center of bat rotation in the plane of the impact motion. These 3-D variables are required so that the actual bat performance of wood and non-wood bats can be computed and compared.

Significance: This study will determine the performance of baseball bats when swung by players using novel 3-D methods and algorithms. The data on wood and current metal and composite bats, published blinded to bat model and manufacturer, will help inform governing bodies on the true field performance of these baseball bats and provide an essential database for the verification of laboratory-based test methods of baseball bat performance.