I sat Burmese with for two back-to-back half hour sittings yesterday without any meaningful troubles and again for half an hour this morning with even less.

I'm beginning to see more and more why these positions are considered favored over other positions, I think. The mental aspect of training seems to be much more poised and natural than before.

But other factors may be at work here. In order to get into these traditional postures I'm working out more, stretching more, etc.

So the mental poise may be a side-effect of the jumping jacks for all I know.