This posture is in Sanskrit called Paravritta Parsvakonasana, and it is the 6th posture in the standing sequence of Ashtanga Yoga Primary Series. This posture requires open hips and some flexibility in the spine, which the previous poses in the traditional Ashtanga sequence give you. All of the standing postures in the Ashtanga series are linked together.
This video shows you how to enter the posture step by step by breaking it down.
