If we are the frame and our horses form themselves under/around us, and if we are correct they will be correct, then it follows that the horse mirrors our position, at rest as well as in motion.
Think of it this way..
even when we think we are doing "nothing" we are doing " something"
If we are doing "nothing nothing" then the horse must make the best of us. we are a passenger, not a rider, and mostly unaware of our effect. Like a pannier or a flourbag.
If we are doing " something-nothing" then even though we are at rest we are exhibiting an aware "toned" relaxation which gives the horse a frame to stand balanced and relaxed beneath us..better for you, better for horse (prevents fatigue, one sided stress on joints etc,)
If we are doing "something-something" then we are actively engaging for an expected response
If we are doing "nothing something" we are moving in quiet harmony, having organized ourselves well, we are able to allow the horse to move freely and lightly and still remain the controlling factor in a very dynamic system.