My guess would be that the fluid dynamics involved in the interaction between the ball and the atmosphere can produce energy transfers between velocity and angular momentum.

” softball pitcher. On her riseball, the speed at the batter was faster than at the release point.”

Appearances are deceptive. Scientists once argued that a curveball is an optical illusion until Dizzy Dean set then straight; fastball pitchers do not have a “hop” on their heaters. Because the laws of physics work everywhere even on ball fields.

Vinny Gambini: Eggs and grits. I like grits, too. How do you cook your grits? Do you like them regular, creamy or al dente?

Mr. Tipton: Just regular I guess.

Vinny Gambini: Regular. Instant grits?

Mr. Tipton: No self respectin’ Southerner uses instant grits. I take pride in my grits.

Vinny Gambini: So, Mr. Tipton, how could it take you 5 minutes to cook your grits when it takes the entire grit eating world 20 minutes?

Mr. Tipton: I don’t know, I’m a fast cook I guess.

Vinny Gambini: I’m sorry I was all the way over here I couldn’t hear you did you say you were a fast cook, that’s it?

Mr. Tipton: Yeah.

Vinny Gambini: Are we to believe that boiling water soaks into a grit faster in your kitchen than anywhere else on the face of the earth?

Mr. Tipton: I don’t know.

Vinny Gambini: Well, I guess the laws of physics cease to exist on top of your stove. Were these magic grits? Did you buy them from the same guy who sold Jack his beanstalk beans?

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Spin matters.

I once helped a college scout with a Juggs gun time a softball pitcher. On her riseball, the speed at the batter was faster than at the release point.

I’ve been behind the plate when a pitcher throws and it seemed to explode as it got to the catcher in front of me. All I cared about was whether the pitch is a strike or not, but it looks weird as heck.

I don’t claim to understand it. I only have seen it in action.

All right, that’s clear enough. But – under what conditions can the ball speed up after leaving the pitchers hand? I suspect there are no such conditions. Therefore, what you are describing is the “exit speed” as the pitcher throws the ball.

Oh.

“Changes speed” means the pitcher will throw a fastball on one pitch and then a change-up / breaking ball / etc on the next pitch. Any batter that is thrown a series of constant speed pitches will eventually time that pitch and hit it fair. A pitcher wants to change speeds to keep a batter “off balance” and either not hitting the ball fair or hitting the ball weakly fair.

That being said, several things affect the speed of a pitch. How much velocity a pitcher puts on the ball at the release is one thing. The spin of the ball is another. Pitches can speed up or slow down because of the spin. (Often times a ball that is barely nicked by a batter and comes back to the screen or hits the catcher or umpire has a higher speed than that of the pitch itself.)

The modern baseball speed guns measure the speed of the pitch repeatedly from release to the batter. That speed will vary but the gun will show the fastest speed. The guns can be set for average speed, but that introduces a human factor into it. The baseball speed guns will display the fastest speed the pitch had over the course of its path to the plate. It is not an average speed.

gitarcarver your response is “the fastest speed over that distance ”

So that’s what the play-by-play guy means when he says a pitcher “changes speeds” on a batter.

Or, more likely, you mean the average speed from pitcher to plate. I didn’t know the radar guns could calculate anything but an instantaneous speed, but I suppose it makes sense that they have that capability.

The speed is measured the from the release point to the plate and the fastest speed over that distance is considered the speed of the pitch.

“Exit speed off the bat” is the speed the ball is traveling immediately after being hit. (Which matters because not only the swing but the “trampoline effect” of metal bats and the “whip effect” of wooden bats.

One of my favorite umpire stories: A player once tossed his bat into the air after Bill Klem called him out on strikes. Klem coolly told him, “Son, if that bat comes down, you’re out of the game.”

The term “exit speed” off the bat always makes me wonder –

When we see or hear that a certain pitch was, e.g., 94 miles an hour, is that the speed when the ball crossed the plate, the average speed from the release point to the plate, or the “exit speed” when the ball left the pitcher’s hand?