Sculpt out the lower body and core using a small stability ball in this 30 minute, targeted workout. Exercises include seated abs, Andrea's favorite Criss Cross variation for the obliques, donkey kicks, and more. If you don't own a small ball, grab a pillow off your bed or couch and fold it in half to give yourself a little extra support. Our favorite ball is also linked out in the "Shop" section of speirpilates.com.