Can Contracting a Stomach Flatten Abs?

Isotonic Contractions

When you blast your abs with crunches, V-ups and leg raises, you're using isotonic contractions to strengthen your stomach muscles. During isotonic activity, your muscles contract and shorten to bend a joint -- your hips, in the case of isotonic ab moves. These activities are the foundation of a well-rounded strength-training program, which should include exercises for all major muscle groups.

Isometric Contractions

When you sit or stand still and tighten your ab muscles, you're performing isometric contractions, which don't involve any movements in your joints. As with isotonic contractions, these moves tone your tummy but won't remove fat. In addition, Harvard Medical School reports that isometric exercises are hard on your cardiovascular system and should be performed sparingly. Some fitness devices, such as abdominal belts, claim to offer an isometric workout by sending electric impulses to your muscles. Doctors use these products to rebuild atrophied muscles among patients who are severely injured or recovering from surgery; however, the devices aren't shown to build muscle definition in healthy adults, according to Columbia University Health.

Exercise Guidelines

To help beat belly fat for good, do strength-training exercises -- which include lifting weights, performing situps and squats or doing isometric contractions -- two to three days per week, allowing muscles two full days of rest between workouts. Perform two to four sets of eight to 12 reps for each move. In addition, up your calorie burning with aerobic activities such as jogging, swimming or biking for at least 30 minutes per day, five days per week. Warm up before all workouts with at least five minutes of light-to-moderate cardio.

Diet and Belly Fat

Along with your muscles, use your mouth to create a flatter belly. Reaching for whole grains like whole-wheat or pumpernickel bread rather than eating white varieties may shrink visceral fat levels, according to a study published in the "American Journal of Clinical Nutrition" in 2010. To attack visceral fat even more, Harvard Medical School recommends filling up on calcium-rich foods like nonfat cottage cheese while skipping trans fats -- listed as partially hydrogenated vegetable oils -- as well as foods containing added fructose.