Knee ups are used in water aerobics to work on your core. Your abs, and your legs and your glutes. When you do knee ups you can do them a bunch of different ways. You can do one knee with a noodle touching your shins. Okay. So, you're lifting your knees up. You can do them twisting, and you don't need to push down on the noodle. Okay. And you can also do them in the deep end. If you had a weight belt on, you could actually do this lifting both legs at the same time. You could also use a weight and you would step on both sides of the weight. This would be an exercise for the deep end as well. Step on both sides of the weight and pick your knees up at the same time. So, you would pick both knees up. Push it down. And you can do them straight, or you could pick both knees up to the side. Okay. So, these are just a couple different ways to do knee ups. Again, they're great for your legs, your butt and your core.