Yeah, you're right.... I wasn't thinking.

With that in mind, I'd use an IK solver on the legs. If you rig the model right, you'll be able to grab it by the root joint and move it up and down without causing the feet to move. The feet will stay in place instead of going through the table and the knees will bend. You'll have to animate the model jumping up on the table but once you keyframe the feet on top of it, they will not move while you animate the root joint (the pelvis) or any other part of the model. There are a lot of tutorials on the net that show how to set up an IK joint for the legs and arms.