Does Running Work Out the Abs?

Anatomy

Your obliques get a good workout from running, but the real star of the game is your rectus abdominis -- the muscle that gives you a "six pack." The rectus abdominis is responsible for holding you upright as you propel yourself forward. Your abs won't be getting the same intense stimulation that crunches give, but the longer duration of running compared to ab exercises means they will still strengthen and tone.

Intensity

In 1994, colleagues Angel Tremblay, Jean Simoneau and Claude Bouchard of the Physical Activity Sciences Laboratory, Laval University, Quebec, Canada, compared weight loss between amateur interval runners and endurance runners. Interval runners ran fast for shorter periods of time while the endurance runners ran longer and slower. After 15 weeks, skin-fold measurements found that the interval runners lost inches as much as nine times higher in some areas. For your next outdoor run, alternate sprinting and fast walking between telephone poles.

Diet

If you can't see your abs right now, there's only one path to a toned tummy -- burn more calories than you consume. If you're working out like a maniac, but packing enough food away to make up for it, the numbers on the scale will remain the same. Higher-carbohydrate meals before runs is fine, but lots of exercise is no excuse for a poor diet. Runners need more protein than the general population. If you're lacking in protein, your body is apt to use muscle for fuel and you'll lose definition. Consume at least half your weight in grams of protein daily.

Frequency

You'll have to do some math with this one. A 150-pound person running one hour at 5 mph -- a moderate pace -- will burn 542 calories or roughly one Big Mac. If you are not exercising and you are not losing or gaining weight, you will lose 0.157 pounds for every hour ran. If you are gaining weight, you'll have to either add runs, restrict your diet or both. For health reasons, the minimum a person should exercise is three times a week.