Pausing and stepping through avatar animations

[Vbents]

I am trying to make an avatar squat/bend/duck given a dynamic height (i.e. the lower the height, the more the avatar appears to be squatting or kneeling or something). I would like to use the built in sitting-down animation, but I don't see anyway to have the avatar jump to a certain frame in the animation and stay in that pose.

If this is not possible, is there another recommendation for changing the avatar height which is more realistic than simply scaling or translating the entire body?

-Ben Trombley