Everything Yoga Fitness Balance Cushion Popular in many Chair Yoga classes, our Yoga Balance Cushion allows you to turn sitting on a normal chair into an abdominal exercise! Because the disk-shaped cushion is full of air, the Balance Cushion creates an unstable surface for you to sit on. Sitting on the cushion forces you to sit tall with good posture, eliminating any back and neck pains you may experience when slouching in a chair. And while you sit with perfect posture, you will be toning your abdominal muscles, without even realizing it!