The Best Exercise to Harden the Stomach

No single exercise will harden your stomach muscles. It takes a combination of good diet, some aerobic conditioning and several exercises to produce a "bikini belly" or "six-pack abs," a flat, solid, well-muscled stomach. Crunches and situps are traditional stomach exercises, but there are many other options, most of which require no special equipment. Plan to work out at least 30 minutes at a time three days a week.

Crunches

The crunch and its variations will work to build stomach muscles. Lie on your back with your knees bent and lift your shoulders off the floor with your abdomen for a basic crunch. Hold a heavy medicine ball or weights on your chest to make it tougher. Vary the crunch by extending your arms overhead and raising your chest and arms and your bent legs at the same time.

Planks

Planks will build a strong stomach. Lie face down on your elbows and forearms or with your hands under your shoulders. Raise your body with your abdomen into a plank position, straight from shoulders to heels, and hold the pose for 30 seconds, longer if you can. Vary the plank by lifting opposite arms and legs while your stomach holds your body firm. Roll on your side and do another plank, with your body on an elbow and side of the foot.

Supermans and Cobras

Lie on your stomach to do a superman and a cobra. Extend your arms in front of you and then raise both your arms and legs off the floor, using your stomach muscles, so your body is in a sort of "Superman flying" position. Hold the pose for 30 seconds, then repeat it. Keep your legs on the floor and your arms at your sides for a cobra. Lift your chest and shoulders up using your abdominals.

Sit Downs

You can do some stomach exercises sitting down. Sit on a straight chair with your hands on the front of the seat and raise your body off the seat; hold the pose 30 seconds. Sit on the floor with your knees bent and your back upright, with arms to your sides, then tuck your legs toward your chest. Vary that with a reach. Straighten one leg and reach toward the toes with the hand on that side; do it five times, then switch sides.