Lie flat on the floor with your lower back pressed to the ground. Put your hands beside your head. Bring knees up to about 45- degree angle and slowly go through a bicycle pedal motion. Touch your left elbow to your right knee, then your right elbow to your left knee. Keep even, relaxed breathing throughout.

Sit on a Swiss ball with your feet shoulder-width apart on the floor. Lean back, so that your back is almost parallel to the floor. Straighten your arms and point them toward the ceiling. Contract your abs, as you would for a crunch, while you reach for the ceiling with your fingertips. Hold the contracted position for three seconds. Slowly lower yourself back to the starting position. Do 10 reps.

The captain's chair leg raise is the second most effective move for the rectus abdominis as well as the obliques. You can do a variety of exercises on the captain's chair, which is a rack with padded arms that allows your legs to hang free and can be found in most health clubs and gyms. The key to keeping this move safe and effective is, first, to avoid swinging the legs or using momentum to bring the legs up. Second, keeping the knees bent will help you focus more on the abdominals and less on the hip flexors.

The exercise ball is an excellent tool to strengthen the abs and is the third most effective move for targeting the rectus abdominis. What makes this move a bit more effective than crunches on the floor is that the legs are often involved in floor crunches. On the ball, the abs do more work.

The vertical leg crunch is another effective move for the rectus abdominis and the obliques.
How to:

1.Lie on the floor and extend the legs straight up with knees crossed.
2.You can place your hands on the floor for support.
3.Contract the abs to lift the shoulder blades off the floor, as though reaching your chest towards your feet.

4.Keep the legs in a fixed position and imagine bringing your belly button towards your spine at the top of the movement.
5.Lower and repeat for 1-3 sets of 12-16 reps.

Sit on a decline bench, with your legs firmly under the pads. Lean back slightly, so that your thighs and torso form a 90° angle. Extend your arms in front of you, so that they form a 90° with your torso, and clasp your hands together. Keeping your back straight, your chest out and your arms straight, make a semi-circle with your arms. With your abs flexed, move as far as you can from right to left and left to right, and do the motion as quickly as you can without sacrificing proper form or range of motion. Work your way up to 60 seconds of continuous movement.

The long arm crunch is ranked the 6th most effective ab exercise, changing the traditional floor crunch by straightening the arms behind you. This adds a longer lever to the move, adding a bit more challenge and difficulty. This move also emphasizes the upper part of the abs, although it's important to remember that your rectus abdominis is actually one long muscle that travels from your lower chest to your pelvis. While you can emphasize one part, any exercise you do will work the entire muscle.

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 1-3 sets of 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.

Add some weight (try 25 pounds) to a multipurpose pulley machine and grasp the handle attachment at shoulder height with your left hand. Square yourself to the machine and take a few steps to the right (away from the machine) until there is sufficient tension. Stand with your feet shoulder-width apart, bring your right arm across your body, and clasp your hands together while holding the handle. Keeping your arms straight and at shoulder-height, use your abs to bring your arms across your body, as though you were making a woodchopping motion. Bring them back to the starting position. Do 10 reps on each side for the excellent core workout.

Place a mat on the floor, lie down on your back and extend your arms above your head. Simultaneously lift your arms and legs toward the ceiling, until your fingertips touch your toes (if you can). Slowly return to the starting position. Do 10 reps.