When it comes to finding the exercises that will help you tone your abdominal muscles most efficiently, part of the equation is finding exercises that feel good and that you'll enjoy enough to do them on a regular basis. That includes doing exercises that target not just the muscles at the front of the torso, but also the obliques -- at the sides and back of the torso. While you could muddle through any number of abdominal exercises, the "experts" have taken the guesswork out of it for you and identified some of the most effective exercises that work the rectus abdominis, or "six pack," and the obliques at the same time.
Step up onto the foot rests of a "captain's chair," also called a Roman chair or a leg-hip raise machine. Your body should be pointed toward the opening in the "chair," so that your back can rest against the back rest.
Rest your forearms against the padded arm rests and grasp the handles with a firm grip. Inhale deeply.
Exhale as you brace your abdominals and flex your knees and hips, working to raise your knees to just in front of your chest. As you lift, your hips will lift off the back rest.
Inhale as you lower your legs down, stopping when your feet are hanging just below your trunk. Repeat the entire sequence 15 to 20 times, and then rest your feet back on the foot rests. According to a study published by the American Council on Exercise, the captain's chair is the most-effective exercise for working the obliques and the second-most effective for working the rectus abdominis.
Lie on your back on an exercise mat. Rest your feet on the floor, causing your knees to be bent. Place your hands behind your head, with each hand just behind its corresponding ear.
Raise your legs off the floor, maintaining a 90-degree angle between your upper and lower legs. Raise them so that the thighs are perpendicular to the floor and the lower legs are parallel to the floor. Inhale deeply.
Exhale as you move your right knee toward your right breast, while at the same time moving the left elbow forward to meet that right knee. Meanwhile, the left leg should straighten out, so that it is close to parallel to the floor.
Inhale as you straighten the right leg, moving it parallel to the floor, and then move the left knee toward the left breast as you move the right elbow toward the left knee.
Exhale and repeat the motion with the right leg. By now, you should start to get the cycling motion of this exercise. Repeat the exercise a total of 15 to 20 times with each leg. According to the ACE study, the bicycle crunch is the No. 1 exercise for the rectus abdominis and the second-best for working the obliques.
Get down on all fours on the floor, using an exercise mat if desired. Inhale deeply.
Push up to a push-up position as you exhale, keeping your hands just below your shoulders and your feet about one foot apart.
Continue to breathe deeply in and out as you hold this position for as long as you can stand it. Time yourself to see how long you can maintain a strong position, and then work to beat that time during subsequent sessions. This exercise is recommended among "Fitness" magazine's best ab exercises. Also called the "hover," it is also No. 4 for obliques exercises and No. 10 for rectus abdominis exercises in the ACE study.