A standard crunch is the most basic form of the move and is the foundation for building a stronger core. Lie on your back and bring your legs up to make your body a right angle – bend your legs at the knees. Put your hands behind your head so your arms are bent into a “V” shape. Then, use your abdominal muscles to lift your head and shoulders off the ground towards the ceiling.
If you want to make this move more advanced, turn a crunch into a sit-up and bring your upper body up further until you are sitting up.