Start With Your Lower Abs

• Lay down on the floor with your back flat and your knees bent, keeping your feet roughly six inches from the ground and your hands either behind your head or resting on the floor next to your hips. Lift your knees toward your chest, while slowly breathing in, until your bottom is off the floor. Then slowly return your legs to the starting position while slowly breathing out. Be sure you feel your lower abs start to burn after the first few cruches, which indicates that they are doing the work here. Repeat this motion 10 to 30 times, depending on your fitness level, then rest briefly before repeating. For best results, repeat this set two or three more times.
  
  

Move On to Your Obliques

• Lay down on the floor with your back flat and your knees bent, resting your left foot across your right knee and your right hand behind your head while your left arm lies out to the side. Bring your right shoulder to your left knee in a twisting motion while breathing in, then lower back to the ground while breathing out. Repeat this motion 10 to 30 times, depending on your fitness level, then rest briefly before repeating. For best results, repeat this set two or three more times. Be sure to switch and do the other side as well (left shoulder to right knee) in order to work both sets of the obliques.
  
  

Finish With Your Upper Abs

• Lay down on the floor with your back flat and your knees at a 90-degree angle, feet flat on the floor. Put your hands behind your head or cross your arms over your chest, whichever feels more comfortable. Lift your shoulders off the ground like you're trying to touch your chest to your knees, while slowly breathing in. Make sure your ab muscles are doing all the work (a sore neck indicates that you may be doing it wrong). Don't sit up all the way, as this is bad for your back and not as effective for your abs. Slowly lower yourself back to the floor while breathing out. Repeat this motion 10 to 30 times, depending on your fitness level, then rest briefly before repeating. For best results, repeat this set two or three more times.
  
  

An Exercise For All Three Muscle Sets

• Lay down on the floor with your back flat and your hands behind your head, your shoulders off the ground and your knees bent in toward your chest. Bring your right knee and left elbow together while extending your left leg to a 45-degree angle then switch, bringing in your left knee and right elbow and straightening your right leg to a 45 degree angle. Continue in this smooth motion, similar to riding a bicycle for 10 to 30 reps, depending on your fitness level. Rest briefly then repeat the exercise two or three more times for best results.