This video we're going to do a core strengthening exercise which is one of the best core strengthening exercises in my opinion. You start by laying down in your back. Once again, your palms flat on the floor straight out to the sides and the T position. Bring your knees up to the 90 degree angle one at a time. And similar to the stretch that we did with the swinging knees, we're going to bring our knees from side to side, but this time, not all the way to the ground. Bring them to about 45 degree angle at each side and hold that for three seconds.

This can be a bit tough on your back. So if you're having lower back pain while doing this exercise, you should probably stay away from it for a while. While until your back pain and receipts little bit. It's great exercise for your oblique abdominal muscles. Really core strengthening exercise overall. Bring your knees from side to side about four times each side, breathing while you do it and you're done.