Now we're going to demonstrate how to do a seated twist. What you're going to do is just start with your hands, so just your body weight first, but then I'm going to progress to a medicine ball to add weighted resistance. So interlock your fingers, okay? Sit up straight so you have good posture on this exercise ball. Engage your core, remember you have no back support so you really have to sit up straight and tuck in your stomach. So what we're going to do is twist, squeeze in the obliques, come back to the center and twist the opposite way. Okay? Sit up straight again as you execute this, twist, come to the center, twist the opposite way. Now we're going to pick up the four pound medicine ball and add weighted resistance. Keep the arms straight again and twist left, twist back to the right. The whole time you're staying upright on the physio ball. So you really feel this in the obliques and the torso. And adding this weight, you feel a little bit more because you added weighted resistance to the stomach. And notice I breathe when I contract. So when I twist, I exhale. And that is the proper way to do a seated twist.