Beginner: Sunbird is a wonderful pose for beginners to help stretch and strengthen the arms, chest and core. The grounded knee should be parallel with the hip, and hips stay level as the opposing leg lifts skyward. For the bow, keep elbows tucking into the body and rest your head along the floor. If this posture is hard on your knees, try adding an extra mat or placing your knees on a blanket.
Advanced: To deepen into sunbird lift, advanced yogis can expand and widen in the collarbone area while pushing outward with the insides of the arms. Squeeze your shoulder blades together but keep your shoulders relaxing away from your ears. In Sunbird bow, keep the head hovering gently above the floor, building immense strength in the shoulders and arms. Your abdominal muscles are super engaged, super energized.