Monday, August 3, 2009

Nerd Alert: Curveball Edition

I'll take a quick break from doing nothing and take a look at one of the consistent marvels of the game: the curveball.
In the baseball blogosphere, there is a whole genre of stat centric sites that try to determine the value of players. Beyond simple boxscore, stat analyzers are another set of writers who examine the physics and effectiveness of specific pitches. Check out Fangraphs for a world of stats you have never even considered.
Check out this article by Dave Allen at Fangraphs from earlier this year. In it, he analyzes the vertical and horizontal motion of curveballs thrown by Adam Wainwright, Roy Halladay, and Brad Penny. Notice this chart. The 0 in the "Vertical Movement" axis represents how much the ball moves vertically from the release point to the plate. Incidentally, the horizontal axis represents how much a ball moves toward or away from a hitter. As you can see, Wainwright and Halladay have much more overall movement on their pitches than Penny, which is why an indicator of why their curveballs are more effective than Penny's.
But also look at this visualization that I have just recently seen. It won an award for optical illusions. (Sorry, I can't seem to embed the visualization.) Follow the directions and notice how much the ball appears to curve away even though it is always moving in a straight line.
Despite the cool optical surprise, I'm not sure what it tells us about curveballs in real life baseball. If this is supposed to somehow represent the deception of a curveball, then it is an aerial view of a curve with no horizontal movement. It doesn't give us an idea of what that motion looks like from a batter's point-of-view. The batter, catcher, and umpire (presumably) have their eye on the ball the whole time. Keeping your eye on the ball in the visualization keeps the sphere in its true path. But certainly, the spin on the ball plays some slight trick on the battery. If a pitch is moving up around eight inches from its release point and the spin creates an illusion of movement, it is a wonder that anyone can hit the pitch, let alone on a consistent basis.
If you are interested in a much more informed analysis of pitches, check out Drew Fairservice's "Kicking and Screaming" recurring feature at Walkoff Walk.
In completely unrelated news, if you ever have to explain the infield fly rule to anyone, just play this song by The Isotopes.

Create a MySpace Playlist at

The Isotopes four-song EP titled Heatseaker is being digitally distributed by Red Scare Industries. Each song has to do with baseball. Sounds so familiar.

Curveball pitching data image courtesy of Dave Allen at Fangraphs.

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