[greymule]

Clearly if the pivot foot is in front of the rubber before the hands separate, it's a crow hop. However, I think that most crow hops we see still come well after the hands separate.

WMB makes a good point that the term "crow hop" is misleading, since it leads people into thinking that the key element is whether the pivot foot became airborne. The airborne concept is reinforced by the advice the books give concerning grooves dug into the mound, about the foot not rising above the level of the surrounding ground.

I think that if the pivot foot does get airborne, then something illegal is probably happening, either a leap or a crow hop.

To me, the determining factor regarding whether there's a replant (ie, crow hop), is the buckling of the knee. Even then, there are so many borderline cases. Another factor is where the arm is when the pivot foot stops dragging. If it's at the top of the arc, it's probably a crow hop. If it has already swung around to where it's below the waist, it's probably not.

Regardless, the crow hop remains a problem in FP. I do hundreds of FP games every summer, including many strong tournaments. I see a zillion borderline crow hops, but neither I nor the dozens of umps I work with call anything but the flagrant violations.

We don't have the problem in baseball. A hop within an overhand delivery would be blatantly obvious.