Contrary to popular belief, diet and cardio work are the main keys to bringing out the definition in the abdominal muscles. Forget all those infomercials about the ab-cruncher, the ab-pulverizer, and ab-dohicky . . . after all, it doesn’t matter how hard your abdominal muscles are if you’ve got a layer of fat covering them. No one’s going to see them.

That said, you need to remember that the key element in ab training is not how many reps and sets you can do but how hard you can contract the abs on each rep.

This applies whether you are using some fancy ab machine or the good old crunch. Make sure your focus in performing your ab movements is on trying to almost push your lower abdominal region into your upper abs and vice-versa.

In spite of how you see most people performing abdominal exercises, your abs during your training should not move like a hinge (as in the conventional sit-up). The segments of the abs really should move towards each other more like an accordion. It's this intense squeezing that tightens and shapes the abdominals.

If your abs are not burning, you're not working them. And, if you find you can do more than say 12-20 reps in any given abdominal exercise, you’re certainly not squeezing your ab muscles together hard enough. You show me someone doing 100 crunches and I’ll show you someone training primarily their hip-flexors as opposed to their abdominals.

Focus on your abs, squeeze them together as hard as you can on each rep, add some extra cardio, and keep your diet clean—these are the keys to having a six-pack year round!