I don't think "root" was a good word to use. I figured, after writing it, that you could also say that movement is rooted in the center, etc. Awful confusing.
If you push a wall, to get the most power, you don't get the ball of the foot involved (not in the path of power atleast), you push against the heel.
I hope that's better. It's been difficult enough to get the sensation while training, let alone describe it