No crow hop, front leg hop.
The monkey butt and the limited brush are related. If you're bent over with your butt out a little it's almost impossible to get your forearm to make contact with your hip or leg. I don't believe that brush is a 'cause', it's a sign of solid mechanics. I say this because when you throw overhand there is no brush and it doesn't have any effect on velocity or control.
Interesting. I am going to have to think about this a bit. I thought proper brush "caused" the effect of control and improved velocity and thus that is why we call brush one of the keys to solid mechanics.
I think that the fact that the exact spot where the contact takes place is very vague (rib cage, hip, outer thigh) keeps it from being a causal factor, for both control and velocity. There some intuitive examples used to justify BI, one is the action of a whip. But a whip is not forcibly halted, just like when you throw overhand the upper arm is not impeded, the energy gets transferred as part of the process. The brick on the hood of a car is another example. Yes the brick flies off when you hit the brakes, but it doesn't accelerate. I am not anti BI, I tell my pitchers not to be concerned about it.
Might prevent injury, too!
Attach an arm to the hood with a brick in the hand of the arm and then compare. All those pivot points make a world of difference when cracking the whip, giving the fingers much more energy than just stopping the car with a brick on it.
