I get a lot of students asking me what Ashtanga Yoga's all about. It's very much different from a Hatha Vinyasa flow. The poses folds in deeper and most of them are pretty challenging. I remembered practicing it in full with Sean Corne and I at tears by the end of it.
Ashtanga yoga was created by yoga master, Patthabi Jois. It consists of a set series of poses done in a vinyasa(old indian language meaning 'flow') style. The Ashtanga style stresses on Ujjayi Breaths, Mula Bandha, Uddhiyana Bandha and Dristis. Bandhas are locks created by squeezing your pelvic floor muscles (Mula) and drawing the tummy into the spine(Uddhiyana). Dristis are where your eyes gazes at, in other words, your focus of attention when you're performing the poses.
Here's a good explanation on ashtanga:-
Click here to learn more:- http://yoga.about.com/od/ashtangayoga/a/ashtangs.htm
And click here as explaine by David Swensen
About the Ashtanga Series of Poses
The first or primary series, called Yoga Chikitsa, is described in Yoga Mala. Yoga Chikitsa, which means yoga therapy, realigns the spine, detoxifies the body, and builds strength, flexibility and stamina. The series of about 75 poses takes an hour and a half to two hours to complete, beginning with sun salutations (surya namaskara A and surya namaskara B) and moving on to standing poses, seated poses, inversions and backbends before relaxation.
The intermediate or second series is called Nadi Shodana, meaning nervous system purification. It cleanses and strengthens the nervous system and the subtle energy channels throughout the body. This series is only introduced when the primary series is strong. It follows the same progression (sun salutations, standing, sitting etc.) as the primary series, but introduces new poses and variations.
The four advanced series are called Sthira Bhaga, which means divine stability. Pattabhi Jois originally outlined two intensive advanced series, but later subdivided them into four series to make them accessible to more people. These series emphasize difficult arm balances and are only appropriate for extremely advanced students.
I do feel that I create the flow in what I think feels right and good for the students. There are reasons behind following the set series of poses in Ashtanga but knowing me, I'm not one to follow rules. I believe like in life, there are different paths to follow, and it's up to us to decide what feels right. My philosophy is, 'just go along with the flow'.........................