Stomach and Ab Exercises

When combined with proper diet and fat-burning cardio exercise, targeted abdominal training can help sculpt a lean midsection. Treat your stomach like any other muscle group and work it two to three times a week, being sure to leave at least 48 hours between workouts so the muscles can repair and synthesize. In every ab workout, try to address all of the three muscles that comprise the abdomen: the front, "six-pack" sheath of muscles, called the rectus abdominus; the internal, corset-like muscle known as the transverse abdominus; and the side striating groups of internal and external obliques.

One-Legged Bicycle

Perform the one-legged bicyle while lying on your back to target the internal and external obliques. Lie with your left knee bent at 90 degrees and your right leg extended a few inches off of the floor. Reach your left arm out to the side with the palm facing down and pressing into the floor. Your right hand rests lightly behind your head. As you inhale, slowly lift the back of your right shoulder off the ground and, as you exhale, angle the front of the shoulder towards your left knee. Repeat 12 times and then switch to the other side.

Stability Ball Crunch

Adding the instability of the ball as your workout surface increases the challenge of this exercise. If you find the crunch on the ball too challenging, perform it on the floor and work your way up to using the ball. The stability ball crunch activates all three muscles of the abdomen.
Sit on a stability ball and place your feet flat on the floor. Walk your body out until your align your entire rib cage on the ball. With your thighs parallel to the floor, rest your hands lightly behind your head with your elbows open wide and keep your neck aligned with the rest of your spine. Remember to exhale as you engage your abdominal muscles and curl your chin very slightly towards the chest. Lift your torso up off the ball towards the thighs while keeping your feet firmly planted. Pause for a second or two and then return to start.
During the exercise, your feet should be hip width apart, but if you cannot maintain your balance try placing them a bit wider. For more challenge, try moving the legs closer together or holding a medicine ball at the chest during the repetitions. Go for two to three sets of 10 to 15 repetitions with a 30-second break between sets.

Scissors

To address the muscles of the rectus abdominus, lie on your back with your legs extended at a 45-degree angle with the floor and your arms alongside your body, palms face down into the mat. "Scissor" your legs by crossing your right foot over your left. Separate the legs just slightly wider than your hips and cross your left foot over your right. Keep your belly tightly engaged and avoid an excessive arch in the spine.
If you find that you cannot help but arch your back, try putting your hands under your tailbone to add extra support. The difficulty of this exercise may be affected by how far your legs are lifted off of the floor. For the greatest challenge, hold them just an inch or two above the floor. Repeat 10 to 12 times. Rest for a minute and complete a second set.

Prone Plank

The prone plank is one of the most simple yet effective exercises for the transverse abdominus. It is used in pilates and yoga but can be part of any training regimen for the abs. Lie on your stomach with your elbows placed under your shoulders and your hands pressed together in front of your face. Maintain a rigid torso and a flat back while you lift your hips off of the mat, supporting yourself on your toes and forearms. Hold up to one minute. Repeat two more times with a 30- to 60-second break between holds. If you master a minute hold for three sets, try increasing the challenge by lifting a leg during the hold or adding a front-to-back rocking movement to create instability. You can also place your forearms on a stability ball to further intensify the effects of the exercise.