Core training works on muscles that deliver strength, endurance, agility.

Byline: Leslie Garcia

DALLAS _ You've begun taking this fitness business seriously: a brisk walk four times a week, weightlifting three. You limit burgers with bacon in their name to a monthly treat, loading up instead on broccoli, baked chips and water-packed tuna.

Well, we hate to break it to you, but you might not be doing enough.

Yes, it's time to add a new phrase to your fitness lexicon: core training.

Team it with aerobics, diet and strength training to form what the experts say are necessities to overall health and fitness.

Simply put, core is as basic as it sounds: the innermost workings of your body. Conditioning the core means combining strength, balance, agility and flexibility of those muscles that control the trunk and spine.

Such exercises don't build bulk. Instead, they strengthen the stabilizer muscles that help hold you up. These are the ones that allow you to walk, climb stairs,…