arm circle speed-univerasal constant

I just spent about an hour reviewing arm circle speeds of about 5 random videos on you tube of Amanda Scarborough and some random recruiting videos. I was trying to see if the arm circle speed of my DD (.38 seconds) was something that needed to be sped up. I have discovered the universal arm circle constant!!! No matter the pitcher....it takes .36 to .40 seconds to complete the arm circle....Two conclusions.

1) Holy crap this surprises me that little kids and college level pitchers have the same cadence.
2) The arm circle speed is basically a non factor in pitching power.

Correct, incorrect? should I switch to light beer from absinthe?

ps- it is also pretty constant that about 55-60% of this is up the circle and 40-45% is down the circle.

scratch that....just found a .33....but still...pretty tight grouping between 10 year olds and top level college players.

You need to push the button quicker on your stopwatch when reviewing you-tubes. Something about how long it takes stuff on dial-up.

abbygale said:

You need to push the button quicker on your stopwatch when reviewing you-tubes. Something about how long it takes stuff on dial-up.

Click to expand...

that would be true.....but....I downloaded all of the videos and put them in software that lets me put a stopwatch on them....one of which was a powerdrive demo that had Scarborough, and an assortment of pitchers from all ages in the same video so it normalizes the possibility of an FPS timing glitch....do not underestimate how obsessed I can be with this stuff. The universal arm circle lives!!!!

Oh boy...we just went through some fluid mechanics problem with riseballs. At least this is a simpler problem, though no doubt someone (*cough*) will say that physics doesn't matter, and that he personally observed 20 years ago pitching that it took only .04 seconds for his arm to make the circle, and that cars are powered by cosmic rays, and that the moon landings were a hoax. But, I digress...

Anyway...the speed of the ball held in the hand of the pitcher has a tangential velocity. The tangential velocity of the ball is its speed immediately after release. The tangential velocity is equal to the (angular velocity in radians per second) * (length of the lever). A 10 YOA girl will have shorter arms than an 18 YOA girls, so the tangential velocity of the ball is greater for the 18YOA girl.

For an older girl to move her arm as fast as that of a younger girl requires more force. The arm of an older girl is larger and heavier, and thus requires more force to move.

Finally, the arm isn't a lever...it is a linked lever system. That is, the arm has an upper portion and a lower portion, linked at the elbow. The tangential speed of the ball in the hand is the the (angular velocity of the upper arm)*(length of upper arm) PLUS (angular velocity of the lower arm)*(length of lower arm).

The key to maximizing the speed at the end of the linked lever (i.e., the ball) is timing.

you are correct....larger circle...more tangential velocity...yada yada yada...that is not the mystifying part.....the mystifying part is that it is so tightly grouped. I would expect there to be more variance and for some pitchers to be getting by on more arm speed/less whip, some to have less speed/more whip....especially with a large age range....I just find it really strange that so many of them fall in this range. Not to nitpick either but when you get into rotational dynamics it changes to Torque=I(dot)alpha....F=MA is really a linear thing and is a vector quantity

no fair- you can't edit your equations once you've handed in your exam...

What Ray said.

To simplify, the only thing that matters is how fast the ball is moving at release. It really doesn't matter how long it takes to swing the arm around in a circle. More then half of that motion is just the setup for the pendulum that has to happen to transfer forward momentum into arm momentum.

-W

Ray...Snuffmeister....luv ya...but the thread is not "where does velocity come from" one of my conclusions was in fact that arm circle speed in and of itself is a non factor. I am posting this because I had seen information on other sites that said things like..."want to increase your pitch speed? Then increase your circle speed by .02 seconds...etc."
When I went to test this info, I found it was complete BS, but it made sense to me when I read it. I also wanted to stake my claim to the constant for posterity. like pi or e....I will call this number jj.

The only thing that matters is the whip:

This argument needs to look at Brooke Boetjer, she is a pitcher at Indiana university... she's a big strong girl that's about 6' tall or better. (long levers)
Anyway if you can find some video clips of this girl. Her arm circle is the slowest I've ever seen, plus there is a slight pause at her 12:00 position. However, she's a 70mph pitcher????