So if you really want to take advantage of the bosu ball, and get really good ab workout, I'm going to show you a few exercises that are very intense. Best ones, I would say, for abs. So you're going to lie on your back, press the small of your back into it, so that you have no space in between your back and the bosu ball. And then what you're going to do is you're going to take your hands behind your head, you're going to lift one leg out, and you're going to keep it straight, and you're going to lift up. And then to make it a little bit more intense, you lift and you reach for that toe. And if you do a few of these, you'll start to feel it right away. And you just got to keep going, as many as you can, maybe fifteen, twenty, would be good, and then you switch legs. Switch to the other side. Again you're reaching. And then another thing you can do that's really intense is bring yourself up onto the ball. Hold on to the back of the ball, or to the floor, which is ever, whichever is more comfortable for you. Your legs are out. You can crunch in and then out. And then of course, if you want to make this a little bit more intense, you bring your arms out to the side. You crunch in. You crunch in, and out, in and out. Another thing you can do is keep your hands back here, and then when you crunch, instead of bending your knees, you keep them straight. And up, straight. So this is going to target a lot of the lower abdominal muscles, but you're definitely going to feel it everywhere else, because you're stabilizing yourself on this ball. And then another exercise that you can do, which targets the obliques but at the same time is really intense, is holding a plank, which in itself is enough. But then if you add something, like a dip of your hips, from side to side, you'll really start to feel this in your obliques as well. And if you had started by doing some of the other ab work before you go into that plank, you're definitely going to feel it right away.