Consider a simple leg joint chain :

*Hip

*Knee

+Ankle

OK, you can grab the ankle IK handle and drag the leg into a pose,
but suppose you wanted to grab the characters hips and push him
down (as if preparing to jump) how do you make the ankles hold
their position, on the 'floor' and have the knees bend logically as
when moving the ankle IK handle up?

Effectively animating with IK, but from the top down?
Whenever Ive laid down a quick IK chain in Houdini, I was always
able to just grab the 'top' of the IK chain and have it work as I described.

But maybe theres an extra step in Maya that Im missing?

Dan