A: The perfect sit up is a stretching pose and keeps all the abdominal muscles and sexual organs strong. It also increases flexibility of the spine.
Raise your arms over your head, simultaneously inhaling, and sit up, keeping your legs straight and your heels on floor. Use the force of throwing your arms toward your toes to help you sit up. Just before upright position start exhalation and dive forward, reaching for your toes, which are flexed back toward you. Grasp the toes and lay your whole body out flat on your legs, touching forehead to knees. Touch the floor on either side with your elbows and stretch forward twice. That’s the double jerk we talk about!
Try to stretch farther each time.
You may find it difficult as a beginner just to lift your body, or your feet may bounce in the air as you try to sit up. This is OK. You can even lift your feet farther and use their downward thrust to sit up. Do not get discouraged and just give each sit up your honest effort and in two months maximum you will do it perfectly.
For sensitive backs, roll over and push up on your hands and knees.