Best Core Exercises Ever

Does it really matter where I place my hands during abdominal exercises? – Iris Berman, San Francisco, Calif.

Iris, is this a trick question? You're asking about crunches which, as many readers know, are not my top pick for working the core muscles of the abdominals and lower back. So I will tell you where you arms and hands should be for crunches, but not without first giving you my two cents on the three best exercises for strengthening and toning your core. I'll even tell you why I like them better.

Back in 2001, the American Council on Exercise commissioned a study where researchers from the University of California, San Diego hooked up electrodes to the waists of a dozen or so subjects and asked them to perform 13 popular core exercises, including basic crunches and moves done on several best selling infomercial gadgets. The electrodes transferred information to a special machine designed to measure the electrical activity of the core muscles as the subjects were put through their paces in order to determine which exercises lit up the most muscle fibers the most deeply and for the longest amount of time. Based on this analysis, the researchers ranked the exercises in order from most effective to least effective.

Which exercise came out on top? Not the crunch. Not even close.

The best three exercises for toning the rectus abdominis (The long flat muscle that runs the length of the front of your middle from the rib cage to the hipbone) are the bicycle crunch, captain's chair knee lift and the ab crunch on the exercise ball.

The best exercises for the oblique muscles (the group of muscles that wrap around the sides of your middle and attach to the lower spine) are the captain's chair knee lift, the bicycle crunch and the reverse crunch. In both instances the basic crunch landed in the bottom three exercises in terms of effectiveness.

The reason these exercises performed well is because they used several muscle groups at once and challenged more muscle fibers with every rep. At the same time, they tended to shut out other muscles like the upper thigh muscles which often take up much of the workload during ineffective exercises or when exercises are performed improperly. They also carried a low risk of poor form and injury.

Still, I'm tossing out the captain's chair and ball exercise from my top picks because they require a piece of equipment not everyone owns. If you have access to either gadget, by all means use them to chisel your abs, but if you don't, substitute with another top performer and one of my personal favorites: The plank. That leaves the bicycle, reverse curl and plank as my top three moves. Before I describe how to do them, a few words about the basic crunch.

Even through the crunch doesn't score well on tests, I think it's fine if you are a basic beginner who hasn't worked her core in a while. The first few times you do them, they will tire your muscles after one to three sets of 8-15 reps and should leave you feeling sore for several days afterwards. To start, fold your arms across your chest. After several workouts, place your hands behind your head with your elbows slightly rounded outward. And after several more workouts, extend your arms straight out in front of you as you lift. Each progressive version adds a little more resistance and thus increases the challenge of the same movement. Once you can do two sets of 15 reps of the straight arm version without exerting much effort, it's time to move on to more taxing exercises. Here they are:

Bicycle [A] Lie on your back with left knee bent towards chest, right leg extended and a few inches off the floor. Place hands behind head, fingertips touching; curl head, neck, and shoulders up. Rotate from middle so that right elbow is pointing towards left knee. (B) Hold the starting position for a slow three count, and then slowly rotate to the other side by bending right knee and extending left leg as left elbow moves towards right knee. Again, hold slow three counts. Continue rotating to complete reps.

Reverse Crunch [A] Lie on your back with legs up off the floor directly over hips and legs extended upward, knees bent slightly or more if you find this exercise too hard to do with nearly straight legs. Rest arms along your sides or behind your head – whichever is more comfortable. You may also find it more comfortable to lift your head off the floor and hold it there while you do the reps; experiment and find what works best for you. [B] Lift tail bone an inch or so straight up off the floor and gently rock legs back just a few inches towards chest. Slowly lower to start.

Plank [A] Kneel on the floor, balanced on forearms and toes. Clasp hands together. Align spine and pull abs in so lower back does not sag. [B] Hold this position for 10-60 seconds. Focus on keeping torso straight the entire time. Perform one to two sets.

Do 8-15 reps of each, starting with one set and building to three sets each. Rest no more than you need to between sets. You can either do all the sets of an exercise first before moving onto the next or do a round robin. Experiment to see which gives you, personally, the best workout.

Let me know what you think. And if you've got an interesting way to work your middle, it's always nice to share with the group. You can post here or so as most people have been doing – tweet me. Lizzyfit@twitter.

And if you're looking to get into interval training, here's how!