It may be tough to get into this pose after sitting at a desk all day. Once you settle in, though, you'll feel a release in your upper back and a stretch in your legs, and you'll want to stay a while.
Start on your hands and knees with your hands shoulder-width apart. Your fingers should be spread and forward, and your thumbs and index fingers should make L-shapes.
Exhale and lift your hips back and up, making an inverted "V" with your body. Keep your arms pulling inward and roll your shoulders back.
Keep your belly pulled in using your core, and engage your quadriceps as you reach your heels toward the floor. Keep your gaze looking back to the middle of the mat, with no tension in your neck.
Variations:
1. Bend one knee at a time and release the heel of the other foot to the ground for a calf stretch. Switch with each breath.
2. From regular down dog, move your hands to the edges and hold on to your mat. Pull your upper body down through your arms for an upper back stretch.
3. From regular down dog, pull your feet forward just a couple of inches. Keep your left arm firming to the ground, then take your right hand and twist your body so your hand reaches your left foot. Hold for a few breaths, then switch sides. This is the Revolved Downward Dog pose.