The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

The conclusions: Within the precision of the tracking data, knuckleball trajectories are just as smooth as those of ordinary pitches. The smoothness conclusion appears to contradict the popular belief that knuckleball trajectories are erratic and often experience abrupt changes of direction. Let me speculate that this belief is the result of the randomness of movement, both in magnitude and direction, giving rise to the perception of erratic behavior.

Link: http://www.baseballprospectus.com/article.php?articleid=15919

I apologize for the multiple postings, just responding to each potentially interested party.

“FWIW, according to pitchFX, Dickey’s knuckle ball doesn’t move at all”

This is completely incorrect. You can’t go by the average movement of the pitch, because the knuckleball doesn’t move in a predictable direction like other pitches. Take a look at Dickey’s movement charts from Brooks Baseball:

http://www.brooksbaseball.net/player_cards/player_card.php?player=285079#HxV

and tell me that the knuckle ball doesn’t move at all.

http://www.brooksbaseball.net/player_cards/player_card.php?player=285079#tab1

Courtesy of Stex’s information, searching has returned this NASA piece on the physics of ball movement;

http://www.grc.nasa.gov/WWW/k-12/airplane/ballforce.html

Those guys have vicious net-nanny restrictions at work, otherwise we’d here a bit more from them. At any rate, the information presented here indicates movement of the pitched ball, vertically and laterally. The Brook’s Baseball link is probably the most compelling with RA’s pitch movement. Looking down on the ball you can see it weaving side to side (near the bottom of the page). Adding the vertical component, you get the corkscrew effect.

An optical illusion effect would of course enhance the movements, but we can’t pin it all to illusion. As Stex alludes too, high speed photography is not subject to illusion.

There are a number of more recent pieces that have more robust approaches to understanding pitches and movement version illusion/perception..

http://illumin.usc.edu/printer/41/curveballs-and-knuckleballs-engineering-principles-at-work-in-america39s-favorite-pastime/

It would be easy to test. Give Dickey some balls with white laces and see how he does.

FWIW, according to pitchFX, Dickey’s knuckle ball doesn’t move at all:

In order the numbers are count, % of total, velocity, horizontal movement (inches), vertical movement (inches)

Fourseam (FA) 124 1% 84.69 -6.53 7.80
Sinker (SI) 2273 19% 85.03 -9.21 4.92
Changeup (CH) 69 1% 76.45 -8.91 3.88
Knuckleball (KN)9506 79% 76.48 -0.19 0.63

Yes, I realize that these data couldn’t measure a “corkscrew” well, but there is no evidence that it goes anywhere in there either….indeed, it moves far less than any of his other pitches, which may suggest it is illusion more than movement that makes it hard to hit.

http://www.hardballtimes.com/main/article/butterflies-are-not-bullets/

Howz dat?

“…knuckleball rotates only one half to one time on its way to the batter, so the airflow turbulence stays on one side of the ball for a while before slowly moving to the other. The ball drifts in the direction of the leading seam, which slowly moves from one side to the other.”

The trouble is that BOTH explanations might have some bearing on KBs. Some KBers rely on illusion while some rely on actual movement. Some, and here’s where I think RA comes in, might have a component of both.

In support of your contention of optical illusion we can have a look at Mike Nickeas’s face: he catches it with his eyes closed but with his glove in constant motion. If this was with some illusion of movement and some actual movement, then that’s how you’d have to do it. Pick out the pitch out the hand, give your brain a split second to track its path, close eyes to catch it, because you can’t trust what they see of the path. The path appears magnified, but the actual path is much tighter, hence a big mitt in the vicinity of the pitch’s path has a good chance of coming up with it.

Regardless of any of this, its going to be VERY hard to hit a ball doing that.

Another possible way to remove the illusion would be for someone to replace the baseball with a solid ball of color. In any case, will all of the recent research on vision and illusion, I doubt knuckle balls do anything….they just look like they do a lot (not unlike many of my co-workers….yes, I get the irony of me posting on a baseball blog while saying that).

http://www.sportsgrid.com/mlb/watching-r-a-dickeys-knuckleball-in-slow-motion-proves-how-difficult-it-is-to-hit/

Is that an optical illusion or is that ball corkscrewing?

Your brain translates the spin in an object to anticipate where the object will next be, when the brain’s guess does not match reality, it gives the appearance of movement when there was none. Because a knuckleball is thrown without any rotation, the slight movement of the threads as it flies toward the plate are constantly mis-interpreted by the eye, giving the appearance of movement where there is none because the brain can not properly guess where the ball will be when it crosses the plate….this is why a knuckleball that spins is crushed, because the brain can interpret where it will be easily.

It is related to this optical illusion phenomenon: http://illusionoftheyear.com/2009/the-break-of-the-curveball/