[nix]

Muscles Get Tired, Bones Don't.

This is simply incorrect, as are most of the conclusions that follow from it. Basically, many muscles can trade off individual contractile fibers to remain under tension all day without perceived tiredness.

You are not a stack of blocks and you can hurt yourself by pretending that you are. Your body includes tensile as well as compressive structures and the whole thing is tied together with a control system. You are not meant to stand up without reflex muscle contraction! (You also aren't meant to sit or stand in one position for very long, but that's a longer discussion).

I trained as an Alexander Technique Teacher, but for the technically inclined I'd recommend reading Moshe Feldenkrais's Awareness Through Movement as an antidote to this way of thinking. See Understanding Balance by Tristan Roberts for more detailed information about postural reflexes.