Re: "resisting" a push part 2
In internal training, there is no "resisting." There is receiving and absorbing of force, and the expelling/expressing or projection of force. To receive, the body must be structured without tensing the conventional muscle groups and positioning that most people would use to brace against a push. Instead, you use "internal" muscles and connective tissues to mold your body into an "arc" (and multiple arcs within the arc) that conveys push-force to the ground instead of letting it push you back or "break" you at your center of mass point.
When you hold your proper structure, and add aiki to it, you both receive and feed/deliver simultaneousl, so when the opponent pushes you, he is bounced back... by his own force, augmented by your own. However, at will you can simply receive the push without returning the force.