All that is required to stand and move is the body`s own natural posture alignment, not strength and tension. This is especially obvious when we are in hanmi or kamae, whatever you use for the word stance.
I'm not sure that the body has a natural postural alignment. Most people I meet need quite a lot of 'correction' in their posture to make them anywhere near aligned.
I have gained a more 'natural' posture from a combination of Aikido, Alexander Technique, Yoga, and I/S training. All of the instruction to get to this 'natural' state felt entirely un-natural at first.
For me, relaxation is every bit as much about mind as it is body. A correct 'stance' without the correct 'mind' is like a pretty cardboard cut out.