Read the first post of the thread where you talked about old age and I had to think of this (AT teacher called Elizabeth Walker, 85 years old in this vid from '99. She's still teaching...):
Watch from 36'' for example...
Nothing to do with IT really, just a coincidence that i had seen this vid and then read the question in the first post.
Thanks for the link. It is very interesting. 85 years old, you say? She certainly is spry and light footed. It's funny; nobody ever really teaches you how to use your body...but there certainly are right and wrong ways to do things. Walking around in daily life; you certainly can see a lot of people's bad (injurious) body movement habits...that you know will cause them pain and bodily deterioration. Can you imagine how much suffering could be averted just only due to simple bad habits being reformed? That is something I find keeps recurring to me.
On a related topic: I seem to recall reading you teach AT (Alexander Technique)... could you say what the underlying reason(s) is that people lift up their chest (like Elizabeth cautions) before they move (/take a step)? I would guess that it is due to a 'disconnection' from the lower body to the upper body...and a weak core. But that is only a guess, and my unlearned opinion.