Lie on your back in the supine position with your legs bent at 45 degrees and your feet flat on the floor.
Place the fingers of both hands underneath the small of your back with your palms facing upwards. Raise your feet off of the floor keeping your legs bent through the knees until your upper leg is at a 90 degree angle to your trunk. At the end of this movement you should be lying flat on your back with your upper legs at 90 degrees to your trunk and your lower legs bent through your knee and parallel to the floor with your toes pointing upwards.
Now raise your head just off the floor and contract your abdominal muscles by pulling the navel in towards your spine. You should feel some pressure on your fingers as your abdominals contract.
Slowly straighten out your legs as far as possible by pushing out with your thighs, maintain the tightness in your abdominals and feeling the pressure through the core of the body onto your fingers, do not lower your feet onto the floor as your legs extend.
Maintain this position until you feel the pressure through the body core begin to relax, then raise your legs back up to the 90-degree position and hold in place for two seconds. Repeat the movement for the desired number of repetitions at a slow pace and do not allow your feet to touch the floor.