That sounds more like good biomechanics to me. The ability to arrange the body so that incoming force is borne by aligned skeletal structure rather than resisted by muscular contraction. Is ki just good physics?
it is. it's what the internal folks called ground path exercise. someone pushed your right shoulder. you focus on create a path between your right shoulder and your left foot, through your body, so that you only feel the pressure at the contact points: righ shoulder where the other person palm touched you and the bottom of your left foot. your body would microscopically readjust itself, if you relax enough (tohei's relax completely which is strange because if you do, you would be a wet noodle. and us guys don't like wet noodle, because it's unmanly.). now see if you can shift (using your intent/mind) the pressure to your righ foot, then back and forth between the left and right foot, then split between the two feet. also, while you are doing this, your body shouldn't move; thus, internal, right? then the next part is to see if you can reflect the push back to the pusher, again, without you physically moving your body, sort of turn your body to a mirror. sort of tilt the mirror so the light (the push) reflecting in the direction you want. this is what some internal folks called jin (mind directed force). if you have attend Ikeda sensei seminar, you heard him mentioned the term "kata" which he described as creating the shape of what you want before the contact made. it's another take on what i described above but a bit more advance. actually, Ikeda sensei created shapes within shapes, i.e. on contact he would reflect your power in multiple vectors at the same time so your body couldn't figure out how to deal with it. normally, your body/mind can deal with one or two force vectors at the same time, but more than 3, your body/mind couldn't handle it. methink, this is called fure aiki which i pronounced as furry aiki or harry aiki which happened to Moe.
also, the internal folks could put themselves into a ridiculous drunken monkey kungfu (don't know why some sick bastard would get a monkey drunk in order to learn kungfu) position that looked like they ready to fall over any time, but if you push on them, then can still do what i just described above, i.e. doesn't have to be body physically aligned to the applied force. they could do it, not optimal, but they could. and yes, i have seen it done, live, as in i was the pusher.