Hey guys, well i started thinking about Collision detection and i dont' think it really helps that much for animation.

So i thought about a different way to do it.

The trick is use IK on the hand and parent the hand to a NONSCALED cube, then parent the nonscaled cube to  the Object that will push on  you or you will push on.

Then move the object and the character's arm will move accordingly, then just pose the rest of the body as needed. It's nice.

Here's a sample of an animation: 3 frames

FRAME 1