This is the first of a series of two classes that lead you into a seated arm bind pose called marichyasana I (A), or pose dedicated to the sage marichi A. This class focuses on strengthening and stretching the key muscle groups that will prevent you from achieving the full pose if they are tight, such as the legs, back, hips and shoulders. The kind of rotation you need in the shoulder joint takes time to establish, so David devotes this class to beginning that release, so you are ready for the second class: Marichyasana I: Full Pose.