For those beginning or those with a weak back.
Upper Abdominal Crunch
Secure your lower back
Bring your knees up toward your chest and cross your ankles and let your knees spread apart.
Adjust the position of your legs until your back is almost flat.
At this point the back usually feels strong and secure with the abdominal muscles just slightly engaged.
The feeling is similar to the lower back balance position
Secure your neck
Make fists with your hands and place them over your ears.
Bring your elbows together
Your neck should stay relaxed (your eyes can stay looking at your elbows)
Bring your elbows up between your knees.
This exercise should put no strain on your neck or lower back.
Lower Abdominal Exercise
Secure your back.
Place your hands, palm down, under your lower back muscles.
Bring your knees up toward your chest as above but keep your knees together and your ankles uncrossed.
When you have secured the lower back note the pressure that is on your hands and do not let the lower back lift up from your hands.
Keep one leg in position and stretch out the other leg. (Bicycle type move)
Make sure you keep the pressure on the hands under your lower back
Swap legs taking the extended leg out as far as is comfortable.
If your have any pain or difficulty with this exercise (other that sore abdominal muscles) then stop the exercise and seek advice from your osteopath or exercise therapist.
Beginners can start with as minimum as 3 repetitions in a set.
After mastering this exercise you can do any abdominal exercise as long as it puts no more strain on your lower back or neck than this way.