We spent some time in Ayurveda--the Indian science of heath and life. Then we moved to bandhas (internal locks), mudras (subtle postures) and pranayama (breath control). The idea is that asana (the yoga poses--what we normally see on the cover of Yoga Journal) can only take you so far.
If asana can release obstructions in prana (life energy--the reason yoga makes you feel so good), then bandhas, mudras and pranayama allow you to focus that energy to create healing.
Shanon even led us in a bit of an experiment. The first day's practice made me feel terrible. Agitated. Annoyed. Hot. But the next day's practice made me feel amazing. The interesting part is that the poses were exactly the same in the same order, but she changed the breathing, bandhas and context. The difference in how I felt was profound.
It was a very personal illustration of the power of yoga--one I'm not likely to forget. The way you structure a practice matters if you want to create benefit for students.