On your hands and knees, exhaling, arch your back like a Halloween cat and let your head hang down.
Then, inhaling deeply, let your belly and spine sag down as your head comes up and you face
forward. If this feels OK on your back, move back and forth between the two positions, breathing
with the movement.
Get your whole back into the swing of it. Exhale, back goes up. Inhale, front comes down.