Kakasana and Bakasana

I love these asanas: they make me feel strong, weightless, graceful all at once.  The trick isn’t in using your arms or shoulders to hold the pose, rather to tighten your core, zipping from your perineum all the way to your intercostals. If you tighten your core, you can hold forever, flying like the birds for which the asanas are named.
In order to do Kakasana (crow pose), start with your feet together. Squat down so that your arms are extended beside your knees, palms flat on the floor. Raise your heels to place your shins (right below your knees) on your triceps (arms should be slightly bent). Tighten your abdominal muscles and pelvic girdle (think about kegels here) to tilt your body forward until you are supporting your body on your arms.
Weight should be evenly distributed throughout your arms and wrists (keep your fingers splayed on the floor). As long as your tighten your abs and mudha bandha, you will be suspended, hanging in the air like a crow! If you find yourself falling forward, think about pulling your hips backward slightly. If you do the opposite and fall backward, think about anchoring your shins by your armpits and holding your palms directly beneath your body (about shoulder-width apart).
If you feel comfortable in Kakasana, move on to Bakasana (crane pose). In this one, you place your knees in the pockets of your armpits, so that your shins line up with your upper arms. Your feet should be crossed beneath your butt. Because your legs aren’t splayed out, this one is more difficult, but totally satisfying!
Both of these asanas really work the transverse abdominus, obliques, and pelvic girdle muscles. Your triceps and biceps brachii will be working, as will your deltoids, erector spinae, hip flexors, and all those lovely muscles that control the movement of our scapula. Make sure that you keep your scapula depressed and neutral in these asanas–you don’t want to bring your shoulders around your ears or create huge chicken wings as you balance.
Done properly, these asanas strengthen and tone the abs, arms, and shoulders, as well as stretching the back and compressing the abdominal/digestive organs.