1. Lie flat on the floor with your lower back pressed to the ground.
2. Put your hands behind your head, then bring your knees in towards your chest and lift your shoulder blades off the ground and engage your core muscles.
3. Straighten your right leg out to about a 45-degree angle to the ground while turning your upper body to the left, bringing your right elbow towards the left knee. Make sure your rib cage is moving and not just your elbows.
4. Now switch sides and do the same motion on the other side.