When looking at the types of abdominal exercises, it is best to divide the exercises into upper and lower ab exercises. Because there aren't two separate muscles that you can isolate, the abdominal exercises we discuss here will work the entire abdominal wall.

There are different clusters of muscle that are separated by tissue in the abdominal muscles and these clusters make up the "washboard" or the "six-pack" effect in a persons abdominals. You can focus on the upper clusters by moving the torso and focus on the lower clusters by moving the pelvis.

For the lower abdominals, lying leg raises and reverse crunches are great abdominal exercises. Reverse crunches can be done on the ground or on an incline sit-up board. All you need is something behind your head to hold. If you use the incline board, use it with your feet lower than your head. For lying leg raises, lie on your back with your hands, palms down under your buttocks.

Raise your legs about 12" off the floor and hold them there. If you're big or have long legs, you should probably avoid this exercise. If you have this problem you can either try bending your knees slightly or just try some other abdominal exercises.

For the upper abs, ab crunches and quarter crunches are excellent abdominal exercises. Lying on your back, put your knees up in the air so that your thighs are at a right angle to your torso, with your knees bent. You can rest your feet on something, like a chair. Slowly raise your shoulders off the ground and try to touch your breastbone to your pelvis. Although the actual movement will be very small, you should try to go as high as possible. Only your spine should bend, your hips should not move.

Do these abdominal exercises fairly slowly to avoid using momentum to help. You can increase the difficulty of the exercise by extending your hands out behind your head instead of keeping them at the side. Make sure you don't jerk your hands forward to help with the crunch, keep them still. If you follow these tips, your abdominal exercises should help you to get the great six pack you've always wanted.