The Most Effective Ab Excercises

It's important to remember that, while ab exercises won't get rid of fat from the belly, a strong core is important for keeping your body healthy and protecting your spine.

Bicycle
 
Lie on the floor and lace your fingers behind your head, knees into the chest. Lift the shoulder blades off the floor and straighten the left leg out while simultaneously turning the upper body, taking the left elbow towards the right knee. Switch sides, bringing the right elbow towards the left knee. Continue alternating sides in a 'pedaling' motion for 16 reps (1 rep is to the right and left).

Captain's Chair or Chair Lifts

If you have access to a Captain's Chair (found at many gyms), stand on the chair and grip handholds to stabilize your upper body. Press your back against the pad and contract the abs to raise the legs and lift knees towards your chest. Lower and repeat for 16 reps. Alternative: Chair Lift (Not Pictured): Sit in a chair and put all the weight in your hands as you lift your hips off the seat, feet on the floor. For a very advanced exercise, lift one or both feet off the ground, balancing on your hands. Lower and repeat for 16 reps.

Ball Crunch

Lie with the ball resting under the mid/lower back and place hands behind the head or across the chest.  Contract your abs to lift your the torso off the ball, pulling the bottom of your ribcage down toward your hips. Lower and repeat for 16 reps.

Vertical Leg Crunch

Lie on the floor and extend the legs straight up with knees crossed. Place your hands behind the head for support and contract the abs to lift the shoulder blades off the floor, as though reaching your chest towards your feet. Lower and repeat for 16 reps.

Ab Roll
 
Kneel in front of the ball and place your hands on the ball parallel to one another. Roll the ball out keeping the hips straight and back straight.  Roll out until you feel the abs engage (don't arch or strain the back) and push into the ball to roll back in. Repeat for 16 reps. 

Long Arm Crunch

Lie on a mat and extend the arms straight out behind the head with hands clasped, keeping the arms next to the ears. Contract the abs and lift the shoulder blades off the floor, keeping the arms straight. Lower and repeat for 16 reps.

Reverse Crunch

Lie on the floor and place hands on the floor or behind the head. Lift the knees, bending them to 90-degrees and contract the abs to curl the hips off the floor, reaching the legs up towards the ceiling. Lower and repeat for 16 reps.

Crunch With Heel Push

Lie on your back with the knees bent and the hands gently cradling the head. Flex your feet and keep them flexed as your contract the abs, lifting the shoulder blades off the floor. At the top of the crunch, press your heels into the floor while pressing your back against the mat and slightly raising the glutes off the floor. Lower and repeat for 16 reps.

Plank

Place forearms on the floor and press up into a flat-back position on the toes, keeping the hips down so that the body is in a straight line from head to heels. Hold for 30-60 seconds, lower and repeat for 3-5 reps.