Lang: A physics comparison of great throws from years past

From Eric Lang at The Hardball Times on June 24, 2014, with mention of SABR member Alan Nathan:

A couple of weeks ago, the baseball world was set ablaze by an incredible throw by Yoenis Cespedes in the eighth inning of a game against the Angels. His impressive throw from the left field corner to home plate was seen by many and ignited comparisons between his arm and many other powerful outfield arms from the past. Most of these debates, however, were based on qualitative and word-of-mouth arguments. What if we could quantify just how good Cespedes’ throw was and compare the qualities of his throw to those of other throws?

Well, we can, as long as we know two crucial pieces of information: time of flight and distance traveled. By carefully analyzing video clips of said throws, I was able to determine the approximate distances and times of flight for each of the throws. To determine the distances traveled I used Google’s distance tool and my best judgment to approximate where on the field the player was. Also, the times of flight were calculated both by counting frames of the videos and by using the tried-and-true method of a stopwatch. Once those parameters were determined, I used Alan Nathan’s trajectory calculator to estimate the launch angle and speed of each of the throws. In using that tool, some assumptions were made and kept constant when analyzing them all. The drag coefficient (Cd) was assumed to be 0.350 and spin rate to be 1500 rpm. Also, I estimated that all of the throws were released from 6 feet above the ground. These parameters play some role, albeit not a very important one in determining the trajectories of the throws. Finally, the correct elevation of the stadium was used in the calculator, which has an effect on the several throws occurring in Denver.

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This page was last updated June 26, 2014 at 1:16 pm MST.