Today's move is all about those obliques (side abs).
How to: Start off in a basic crunch position. With your hands supporting your head, lift your shoulders off the floor bring your opposite elbow and knee to meet in the middle. The other leg should be elevated off the floor. Now repeat on the other side.
Now you: Try the bicycle ab song challenge. Just put on your favourite track and keep this move going for the duration. Definitely an ab killer!!