Page 1 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Is the Gyroball a Miracle Pitch? Alan M. Nathan University of Illinois at Urbana-Champaign websusers.npl.uiuc.edu/~a-nathan/pob The hype The science Does he or doesn’t he? So, is it a miracle pitch?

Page 2 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Why all the Hype about the Gyroball? Daisuke Matsuzaka: Does he or doesn’t he?

Page 3 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Secret of the Demon Pitch by Kazushi Tezuka and Ryutaro Himeno Tezuka: pitching coach who “invented” the pitch. He also has an instructional DV Himeno: computer scientist who discovered its properties with elaborate simulations

Page 4 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? “It's quickly becoming the Bigfoot of baseball, an urban legend born in a Japanese lab and racing across the Internet. They call it the "gyroball"—the exact translation is probably closer to "Demon Sphere Gyro Ball"—and it's either the first new pitch in nearly four decades, or a complete and total sham.”—Popular Mechanics, 11/06

Page 5 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Seattle PI 10/18/06 Are these claims scientifically sound? Does anyone throw it?

Page 6 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? The trajectory of a pitched baseball in flight is governed by the gravitational force and the Magnus force on a spinning baseball. Gravity makes the ball drop by 3-4 ft, depending on speed The Magnus force deflects the ball by an amount that depends on the spin (rpm), the speed, and the orientation of the spin axis. The Science of a Baseball Trajectory

Page 7 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? The spin axis is the line connecting the south to north pole (“right-hand rule”) The Science of a Baseball Trajectory spin axis

Page 8 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Magnus force causes ball to break in direction that front edge of the ball is turning spin axis deflection rotation Example: straight overhand fastball as viewed by batter— upward break opposing gravity The Science of a Baseball Trajectory

Page 9 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? More examples, as seen by batter spin axis “12-6” overhand CB: downward break overhand FB: upward break spin axis deflection spin axis

Page 10 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Sidearm curveball by RPH breaks away from RHB More examples, as seen by batter 3/4 fastball by RHP breaks up and in to RHB

Page 11 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? More examples, as seen by batter Note that spin axis is tilted a bit forward. slider by RHP breaks down and away to RHB cut fastball by RHP breaks up and away to RHB

Page 12 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? mph mph mph mph Break (excluding gravity) of Matsuzaka’s Pitches (as seen by batter)--thanks to MLB Gameday horizontal break (inches) vertical break (inches) ¾ FB CB/SLD Cut FB SFFB?

Page 13 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Magnus force also depends on angle between spin axis and direction of motion. Largest when angle is close to 90 o : Zero when angle is 0 o : the gyroball side view “normal” pitch with sidespin Angle=90 o Maximum force gyroball Angle=0 o Force=0

Page 14 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Courtesy, Ryutaro Himeno For pure gyroball, only force is gravity. no sideways break drops ~15” more than FB

Page 15 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? An aside for physics geeks…. When spin axis of a spherical ball coincides with the direction of motion, there is complete symmetry about that direction. So, the ball has no way of “knowing” which way to break. Therefore, there can be no break.

Page 16 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Is this all “theoretical”? Proceedings of the Asia-Pacific Congress on Sports Technology, Tokyo, 2005 Translation: Magnus force = 0 for gyroball …exactly as expected theoretically

Page 17 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? from The New York Times: they got it exactly right!

Page 18 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Seattle PI 10/18/06 Pure nonsense!

Page 19 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Some additional thoughts l Gyroball thrown mph drops more than fastball  Sort of like a splitter, but even more drop l May look like slider to batter Batter sees “red dot” and expects slider red dot identifies slider expects break to right “backup slider”—in former days, a mistake slider gyro

Page 20 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Clip from Kazushi Tezuka’s Instructional DVD

Page 21 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? If spin axis tilted slightly upward, ball breaks a little sideways: “gyroball with side force”. Variation #1 15 o tilt gives ~4” break to side

Page 22 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? If spin axis tilted slightly toward 3B, ball breaks a little upward: “gyroball with lift force” Variation #2 15 o tilt gives ~4” break up

Page 23 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? mph mph mph mph Log of Matsuzaka’s Pitches (as seen by batter) Daisuke Matsuzaka: Does he or doesn’t he? several candidates

Page 24 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? “While (Ranger’s lefty reliever C. J. ) Wilson said he threw the pitch against both Alex Cora and Kevin Youkilis in the eighth inning of a May 26 game between the Sox and Rangers, neither batter could verify the claim.” Manchester Union Leader, 6/30/07 Nor can I

Page 25 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Is the Gyroball a Miracle Pitch? l We have come full circle  Gyroball does not have crazy trajectory people have claimed  Gyroball trajectory determined entirely by gravity  Therefore, it seems like a useless pitch l But….  If batter is expecting a typical fastball…  If batter misinterprets spin as a slider…. l My personal view: gyroball is a useful but not a miracle pitch

Page 26 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? Thanks to …. l R. Himeno for sharing his diagrams l Dave Baldwin for teaching me about the craft of pitching l Will Carroll (BP) for some helpful conversations l Dan Fox (BP) for providing the Gameday pitch logs for Matsuzaka l The bloggers at SoSH for asking good questions Want to know more: webusers.npl.uiuc.edu/~a-nathan/pob/gyro Science and Baseball meeting, 4 PM today, DR43

Page 27 SABR37, July 27, 2007 Alan M. Nathan Is the gyroball a miracle pitch? spisspis spin axis