For more abs exercises get the book, Boot Camp Six-Pack Abs.
Here are some of the exercises from the book, Boot Camp Six-Pack Abs:
Lie on your back with knees bent. Firmly hold weighted plate or other item, such as a sandbag behind your head or across your chest. Contract your abs and raise your upper body while keeping your lower back on the bench and raising your upper body as high as possible. Then return to the starting position with your shoulder back on the bench. Perform 3 - 5 sets of 10 to 40 repetitions each. Add more weight or less, depending on your level of strength and endurance.
Here’s another great abdominal exercise. We’ll call it the alternating elbow crunch. You’re on your back. Your hands are clasped behind your head. Your left leg is bent. Cross your right leg over your left knee. Take your left elbow and reach for your right knee and back down. That is one rep. Use a smooth motion. Don’t be concerned if you can’t reach your leg with your elbow. Do the best you can. Remember, by performing the exercise you are working those muscles! Now switch off by crossing your left leg over your right knee, reach for your knee with your right elbow and do it again.
Sit on the ball and then gradually walk your legs forward and lie back on the ball until your shoulders and head are hanging off the ball with your knees and hips bent. Bend your body so that your back is contoured over the ball. Contract your abs to raise your upper body while twisting your upper body in one to the right and return to the starting position. You may alternate by twisting your upper body to the right and then the left or your can perform all your repetitions of a set by twisting to one side only and then the same number of reps for the other side.
With the atomic sit-up we are now going nuclear. Just kidding. Some think this is an exercise from the Cold War. Lie down on your back with legs extended and arms extended to your sides. The starting position is with legs six inches off the ground and extended. Now pull your knees and your chest to the middle where you are in a position balanced on your butt. Your body is briefly in that jack-knifed position. As you move into this position, bend your elbows so that your hands are at your shoulders. Now lower your legs back out to the extended position with feet six inches off the ground with your arms extended. That is one repetition. You may need practice before your body can perform this exercise. Perform 3 - 5 sets of 10 to 20 repetitions each.
Get Colonel Bob's book, Boot Camp Six-Pack Abs for more ab exercises.