Below is the correct way to do a Sit up, watch the video below.
1. Lie on your back on the floor, with your knees bent and your feet flat on the floor.
2. Place your hands behind your head, elbows pointing out.
3. Slowly raise your shoulders and upper back off of the floor, pause and lower your shoulders back on the floor.
Remember -only lift your head and shoulders off of the floor. Don’t sit up completely.