It's abs-olutely time to straighten up.(Knight Ridder Newspapers)

Byline: Nancy Cole

Are you hard core? If you've recently added a Pilates-based routine to your exercise program, you could be. Pilates, a discipline created by Joseph H. Pilates more than 90 years ago, focuses on strengthening the body's core (abdominals, lower back and spine).

The discipline relies on core development, stabilization and energy to promote the fluid movement of the body as a whole. It enhances coordination, flexibility, balance and alignment of the entire body, thereby refining the body's movements.

Pilates can improve your posture, tighten your abs and help stabilize your body for everyday functioning, thus helping to prevent lower back injuries. A Pilates-based program or Pilates-fusion type class can be a nice complement to your resistance and cardiovascular training.

A great core-strengthening move is the Single Leg Lift on a stability ball. Using a stability ball forces your stabilization muscles to work harder than if you were to perform this move on the floor.

Lie on your back with your arms extended by your sides and your palms facing the floor. With your legs outstretched, place your calves and your heels on top of the ball. Once you have your balance, squeeze your glutes to raise your ...