For the original question:
We do our ba shi almost every day of class (4 times a week).
we do it for 30~60 seconds per stance so 4-8 minutes total. depends on the day and what else I have planned for class.
Sometimes (maybe once a month) we'll do ma bu for 2-4 minutes w/o doing any of the other stances.
I like to mix stuff up a lot though. The other day I had them do 10 break falls then, 30 seconds in a posture, then another 10 falls, repeated till they did 30 seconds in each stance. They ended up w/ 4 minutes of stance training and 80 falls in about 8 minutes total.
they hated me
also, we don't just exercise our legs while doing posture training. Our arms are held in different blocks and strikes while holding the posture so our arms are getting some development as well.
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