The ground is not solid, it is loose and unstable, especially inside a pitchers circle.
Hal,
I was being general in my use of the word "ground". The pitcher's rubber is attached to the ground.
The ground is not solid, it is loose and unstable, especially inside a pitchers circle.
If we are to get this technical. Let's jump to the closer. 100% of power is derivered from between the ears.I think the more accurate way to determine what the legs do is try and pitch while sitting/kneeling on a large medicine ball (Abbott) or a chair so that the legs are not in contact with the ground. Even in Ks, you still have the leg providing resistance. Compare the non-leg throwing speed with a real pitching speed.
When my DD is having a problem with her pitching I look at the legs first. Her drive from the rubber tells me a lot. Walk throughs are a prime example. I'm sure my DD throws 3-4mph faster in a walk through. Energy is produced through motion. Less motion and there's less speed.
I think that generally, kids throw harder when they drive harder. I wouldn't say the speed actually comes from the legs, but more that when you drive harder, the hands need to speed up to keep the timing.