could move until the offensive player left his feet, i.e. was physically in the air. That led to a lot of undercuts and close calls. Sometime in the last 5 or 10 years they changed it to the offensive player starting his upward movement, although still on the ground, as the point where the defender can't move. Still have to be in a defensive position, both feet on the ground, and take the contact in the chest/body.

In any event, it's a tough call, made all the more so by the guys that intentionally try and take charges on basic play away from the basket.
[Post edited by 133743Hokie at 03/26/2018 10:41AM]