There IS a python script called "Jiggle" or something like that, tha applies the poser physics to anatomy.  I never used it, so don't know how useful it is.  It might be over at vanishingpoint.com.  That is very helpful, but it might be a starting point.  Other people have solved this problem, I just don't remember much about it, since I do no do animations.

I cannot save the world. Only my little piece of it. If we all act together, we can save the world.--Nelson Mandela
An  inconsistent hobgoblin is the fool of little minds
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