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Past Research

Recently, the Sports Biomechanics Laboratory completed two projects concerning baseball aerodynamics. The first project determined the initial conditions of the baseball pitch. The second, uses these initial conditions to duplicate the pitch with a pitching machine.

Initial Condition Determination
Completed 06/18/1998.

Primary Researcher - LeRoy Alaways

The focus of this project was the determination of the effect that angular velocity has on the trajectory of the pitched baseballs. This was accomplished by estimating the initial conditions (position, translational velocity, and angular velocity) of the pitch by constructing an accurate aerodynamic model of the pitch and then simulating a pitch with a guessed set of initial conditions. The results of this simulation were then compared with an accurately measured trajectory and the residual vector is computed. This residual vector is then minimized iteratively, by changing the values of the initial condition vector using a nonlinear least squares method. The results of this procedure are highly accurate estimations of the initial conditions of the pitch (see figure below).

Results of this research include the lift, drag and cross-force coefficients for pitched baseballs. A copy of the dissertation and other baseball papers can be found on the following link: Dissertation and papers

Pitching Machine
Completed March, 2000.

Primary Researcher - Sean Mish

A machine to throw baseball pitches accurately and repeatably has been developed. This machine will release a ball with specified angular and translational velocities to study the effect of release conditions on the ball's flight. In order to control both the spin of the ball and its translational speed, separate mechanisms have been dedicated to each of these tasks. The parameters under automatic control for each pitch are: release angle (both pitch and yaw), translational velocity, spin axis orientation, and spin rate. This machine is intended for use as a scientific instrument. There are currently no plans for commercial production. Initial development was completed in March 2000, additional refinements in the machine can and will occur with incoming students in the following years.
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Kenny...Better check that stuff you're smokin'.

You can write a PhD dissertation on just about anything. Doesn't mean as much as it used to.

Curve balls "curve" when thrown and if you don't believe it, don't believe it.

Obviously, you've never faced a pitcher who had a very good curve ball. Some high school pitchers do have good curve balls. Watch the LL World Series and you'll see a few curve balls.
That quote, "No man that ever lived..." Appeared in New Yonker Magazine in 1941 as tongue in cheek mocking of the debate over whether a CB curves.



We need to get back to basics. Lesson Number One: How to Pitch.

The debate over whether a curveball actually curves began maybe 20 minutes after the pitch was perfected by William "Candy" Cummings in 1867. (I follow the account given by LeRoy Alaways in his 1998 doctoral dissertation for the University of California, Davis, "Aerodynamics of the Curve-Ball: An Investigation of the Effects of Angular Velocity on Baseball Trajectories.")

The matter wasn't resolved quickly. As late as May 1941, in a mock letter to the editors of the New Yorker, one R.W. Madden quoted a baseball sage as saying, "Now I'll tell you something, boy. No man alive, nor no man that ever lived, has ever thrown a curve ball. It can't be done." This declaration, though clearly tongue-in-cheek, begat much acrimonious discussion.

A few months later Life magazine, apparently figuring that for one week it could forgo the usual fluff about Japanese maneuvers in the Pacific, published a photographic analysis purporting to show that "a baseball is so heavy an object . . . that the pitcher's spinning action appears to be insufficiently strong appreciably to change its course."

Too bad Life hadn't been around a half century earlier--no doubt it would've proclaimed that heavier-than-air flight was impossible. Truth was, the reality of the curve had been demonstrated as early as 1877, when a couple of pitchers--one a lefty, the other a right-hander--threw curveballs around boards that had been set up at intervals along a straight chalk line. (The pitches in question obviously curved more from side to side than up and down.) The scientists who've gotten into the act since the 1940s have used strobe photography, wind tunnels, and other sophisticated technology, but their conclusions have all been the same: Yes, a curveball curves--in the hands (well, having left the hands) of a skilled pitcher, as much as 18 inches.

The reason the ball curves involves something called the Magnus effect. It boils down to this: A pitcher throwing a curve imparts spin to the ball. As the ball flies through the air, it leaves a wake behind it. Were the ball not spinning, the wake would be roughly symmetrical, as shown in the left-hand illustration. Since it does spin, the wake is deflected to one side (the side where the spin is counter to the motion of the air rushing past), as shown in the right-hand illustration. Intuition alone (and that failing, the law of conservation of momentum) should convince us that if the forces acting on the ball are such that they deflect the wake one way, they simultaneously push the ball the opposite way. Thus the curve.

How many different ways can the pitcher throw the ball? There's a seemingly unlimited number of names for pitches: fastball, curve, slider, breaking ball, sinker, changeup, screwball, knuckleball, split-finger fastball, two-seam fastball, four-seam fastball, cut fastball, slurve, forkball, and lots more. (I grant you that some of the preceding are basically synonyms.) I won't attempt to sort them all out, other than to say they involve different grips, release speeds, degrees and angles of rotation, and so on. (For a not-too-technical analysis of common pitches, see The Physics of Baseball by Robert Adair, onetime "physicist to the National League," 1990.) The extreme case is surely the knuckleball, which rotates only a half spin or so en route to the plate (for comparison, fastballs usually spin 9 to 12 times) and whose aerodynamics change so drastically in consequence that it can curve one way and then another.

Pitching isn't illusion free. Despite appearances, breaking balls don't really break--that is, the ball doesn't change trajectory abruptly in midflight ("fall off the table," in baseball parlance). The curve of a spinning ball--i.e., anything but a knuckleball--is always smooth. Likewise, the ball can't speed up on its way to the plate, although if the boys in the dugout think it does, the pitcher is doing his job.

So, think you've got a pretty clear idea how to throw a curveball now? Good. Next week we'll turn to Lesson Number Two, which may be even more useful to certain parties in the baseball business: The Importance of Middle Relief.

Personally, I'm thinking it's that Kenny can't throw a curveball, has lost a few feet (read: about 60) off his fastball and his idea of a changeup is red wine from white, not that there's anything wrong with that.

If the ball is bouncing, why is it still called a ground ball? Isn't every ball a ground ball, eventually?

Sorry, couldn't help myself.
Last edited by OldVaman
Originally posted by OldVaman:
Personally, I'm thinking it's that Kenny can't throw a curveball, has lost a few feet (read: about 60) off his fastball and his idea of a changeup is red wine from white, not that there's anything wrong with that.

If the ball is bouncing, why is it still called a ground ball? Isn't every ball a ground ball, eventually?

Sorry, couldn't help myself.
Just because there might not be a curveball in his area doesn't mean you need to make up some assinine report about info that is really irrelevant. If you want to learns how to throw a curve, there are many players, parents, coaches and others that will help you man.
Larry Evans

I am not into the physics of the game but when you face a 95 MPH fastball and it is bearing in on you and you miss it as it flies by you in the batters box you tell me it doesnt rise.

Watch videos of pitchers and tell me you dont' see the ball rise at times

Next you will tell me that pitches do not curve nor do they slide

May I ask where your location of AS is ?

One last thing --I Never saw a rising fastball down and away--have you?
Last edited by TRhit
The best-selling book, Physics of Baseball by Robt Adair, professor emeritus of physics at Yale says:

1) Curveballs curve
2) Baseball pitches never rise (but appear to)

I don't understand why they can't rise given enough spin, but proving whether or not they do is easy using modern strobe photography techniques: Take a series of high speed photos of a "rising" ball against a wall with reference straight lines on it (kinda like a police line up).

Therefore, I think that it is well established that pitches don't rise

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