The overall best exercise for strengthening your abs is the bicycle maneuver.

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It's often said that the best fitness program is one you'll stick with. True enough. If you don't like what you are doing, you'll look for a reason to quit. But if you're going to invest time and energy into getting fit, you also want the biggest bang for the buck. So here are three of the best exercises any woman can do.

Exercise No. 1: Bicycle the Abs

A study of 30 healthy women and men, ages 20-45, sponsored by the American Council on Exercise (ACE) and led by Peter Francis, Ph.D., at the Biomechanics Lab at San Diego State University, compared 13 of the most common abdominal exercises and ranked them from most to least effective. Overall, the best exercise for strengthening the rectus abdominus, which includes the long flat muscles extending along the front and sides of the abdomen, is the bicycle maneuver. Here's the ranking of the 13 abdominal exercises from most to least effective.

"The bicycle kick is the overall best abdominal exercise," agrees Michael Stefano, a 20-year veteran of the New York City Fire Department and author of The Firefighter's Workout. Having strong abdominals helps you maintain balance and provides a foundation for many other activities.

How to Do It

Lie on your back on a mat or padded carpet with your knees bent and feet flat on the floor. Press your lower back into the floor, engaging your abdominal muscles, as you put both hands behind your head (don't pull on your head). Bring your right elbow over to your left knee, and then bring your left elbow over to your right knee in a twisting, bicycle pedal motion. Continue to breathe naturally. Alternate opposite elbow to opposite knee with hands interlaced behind your head in a slow and controlled manner and with full extension of each leg on every repetition.

Breathe naturally, extend your legs fully to increase intensity and perform the motion very slowly. Keep your knees bent throughout the movement, while you tap your feet to the floor (instead of extending your leg straight out), to decrease intensity. Repeat to muscle fatigue.

Goal: Two sets of 20-30 repetitions