Long Arm Crunch

   This move, ranked 6th in the ACE study, emphasizes the upper part of the abs. To do it right:
       1. Lie on a mat and extend the arms straight out behind the head with hands clasped, keeping the arms next to the ears.
      2. Contract the abs and lift the shoulder blades off the floor.
      3. Lower and repeat for 12-16 reps.

Reverse Crunch

                It may seem like the reverse crunch is for the lower abs but, remember, the rectus abdominis is one long muscle, so you can't separate upper from lower. To do this move right:
       1. Lie on the floor and place hands on the floor or behind the head.
       2. Bring the knees in towards the chest until they're bent to 90 degrees, with feet together or crossed.
       3. Contract the abs to curl the hips off the floor, reaching the legs up towards the ceiling.
       4. Lower and repeat for 12-16 reps.
       5. It's a very small movement, so try to use your abs to lift your hips rather than swinging your legs and creating momentum.

Common Errors:

The crunch is an exercise that can be done in what looks like a correct manner but resulting in no meaningful work. Be sure to squeeze the abs very hard at the top of each crunch. If you can talk to somebody (and be easily understood) while doing crunches, you are probably not squeezing hard enough.

Yanking on the back of the head can lead to neck pain. If you have a tendency to do this, keep your hands off to the sides of your head without actually letting them touch your head.

This is often done in an effort to get out of the bottom to return to the top. Each rep should be performed slowly and under control. This muscular tension is what will work the abs best.

Don't hold your breath all the time when doing ab work. The abdominals play an important role in breathing. By limiting breathing, you will be limiting the work on your abs.

Interlocking your fingers behind your head limits the range of motion of your abs by tying it to shoulder and lat flexibility. If you have tight shoulders and do this you won't be able to stretch back as far. Keep your hands and forearms off your head.

Full Vertical Crunch

   In a full vertical crunch, you really work the abs by involving both the upper and lower body. To do it right:
       1. Lie on your back and extend the legs up towards the ceiling.
       2. Place hands behind your head (lightly cupping it) and contract the abs to lift the shoulder blades off the floor.
       3. At the same time, press the heels towards the ceiling, creating a 'u' shape with the torso.
       4. Lower down and repeat for 12-16 reps.

Ab Rocker

   The Ab Rocker (or roller) is number 9 for targeting the rectus abdominis. To do it right:
      1. Sit on the Ab Rocker and grab the bars in each hand.
      2. Contract the abs to rock forward.
      3. Release and repeat for 12-16 reps.
      4. Go slowly to reduce momentum. Try to focus on the abs rather than pushing with the arms.

Plank on Elbows and Toes

    The plank exercise ranked number 10 in the ACE study and is a great way to build endurance in both the abs and back, as well as stabilizer muscles. To do it right:
     1. Lie face down on mat resting on the forearms, palms flat on the floor.
     2. Push off the floor, raising up onto toes and resting on the elbows.
     3. Keep your back flat, in a straight line from head to heels.
     4. Tilt your pelvis and contract your abdominals to prevent your rear end from sticking up in the air.
     5. Hold for 20 to 60 seconds, lower and repeat for 3-5 reps.