Welcome to my site devoted to research on the physics of baseball. My particular research interests are two-fold: the physics of the baseball-bat collision and the flight of the baseball. I have done quite a bit of independent research in both areas. I am also heavily involved with several areas of practical interest to the game. One is characterizing, measuring, and regulating the performance of non-wood bats, an area for which I have served on committees advising the NCAA and USA Baseball. Another is exploiting new technologies for tracking the baseball, such as PITCHf/x, HITf/x, and TrackMan, for novel uses in baseball analytics. But this site does much more than catalog my own work. It attempts to provide links to much of the high-quality work done over the past decade or so on various aspects of the physics of baseball. If readers know of a site that I have overlooked, please contact me.
Recent Research Highlights
by Kate McSurley and Greg Rybarczyk
by Greg Rybarczyk
This article was published in The Hardball Times Annual 2011. It begins with a brief introduction to the FIELDf/x system, an enhancement to the pitch-tracking PITCHf/x system. FIELDf/x uses multiple cameras to track everything on the playing field: the fielders, the umpires, the base runners, and the batted ball. The bulk of the article, A FIELDf/x Application: True Defensive Range, is written by Greg Rybarczyk, inventor of the ESPN Home Run Tracker. It is the finest piece of publicly available analysis using FIELDf/x data that I have seen and is a must read for anyone interested in advanced fielding metrics. Thanks to Greg and to Dave Studeman, manager of The Hardball Times, for allowing me to post the article here. Greg talked about this work at the annual PITCHf/x Summit in 2010 and 2011.
On June 13, 2012, R. A. Dickey pitched at one-hitter against the Tampa Bay Rays at Tropicana Field. In the bottom of the third, Dickey struck out Will Rhymes with the pitch thrown in the above high-speed video clip. Take a good look at the pitch. Being careful not to be fooled by the upward movement of the camera or the movement of the catcher, see if you can tell that the pitch undergoes two distinct changes of direction. Shortly after release, it appears to move abruptly to the right; later it moves just as abruptly to the left. This pitch clearly seems to be an exception to the conclusion I reached in my analysis of Dickey and Wakefield pitches from the 2011 season that knuckleball trajectories are just as smooth as those of normal pitches. But is it really? To find out, click here for a complete analysis.
A link to a video of a dramatic demonstration that the batter's grip plays no role in the fate of the batted ball
On May 27, 2012, Todd Frazier hit a home run with his hands barely gripping the bat. Watch the video starting at about the 32-sec mark. Note in these images that the top hand is not in contact with the bat and the bottom hand is very loosely in contact with it at the moment of collision with the ball. So, the bat is essentially a free object. Nevertheless, the ball is hit for a home run, demonstrating in dramatic fashion that the batter's grip plays no role in the ball-bat collision. Viewers with a sharp eye will see the bat actually vibrate after it leaves Frazier's hands. See The Role of the Batter's Grip in the Baseball-Bat Collision for links to extensive discussions of these issues, including a link to even more discussion by Dr. Dan Russell, a friend and fellow bat researcher. I talked about this event at the SABR42 convention and you can view a brief video clip here.