Crunches are a go-to exercise for achieving six-pack abs, but they won't do much for your weight unless you combine them with a total diet and exercise strategy. Plus, targeting only one muscle group can cause balance problems, so focus on strengthening all areas of your body. If you work your stomach but not your back, for example, you'll grow stronger on your front side only, which could affect your beautiful posture.
Crunches on Machines
Abdominal machines target your stomach for hard-core toning. Most models allow you to add weights or adjust resistance, providing greater strength improvements than standard crunches. At the gym, you'll find lying and seated crunch machines to work the rectus abdominis muscle on the front of your torso, as well as twisting and side crunch machines to work the oblique muscles on your sides.
Crunches and Calories
There's only one tried-and-true way to lose weight: Burn more calories than you eat. And while using abdominal machines does induce calorie burning, the numbers are less than impressive. Actual burning depends on your vital stats as well as resistance level, but on average, a 155-pound woman burns about 112 calories in 30 minutes of weight training. It takes a deficit of approximately 3,500 calories to lose 1 pound of fat, so if you relied weight training alone it would take about 31 sessions to lose a single pound.
Succeed at weight loss by adding cardio exercise and a healthy diet to your weight-training routine. Fit aerobic activities such as jogging, cycling or using the elliptical machine into your schedule most days of the week, as these moves torch calories rapidly. Steer clear of the drive-through, instead preparing meals at home with fresh, unprocessed ingredients. Fill your plate with fruit, vegetables and whole-grain pastas, breads and tortillas, which will keep you full for hours with their high fiber content. Instead of fatty fried chicken or hot dogs, opt for lean proteins such as garbanzo beans, seitan and fish.
You may be eager to whip your abs into shape, but don't torture your muscles with too much weight or too many repetitions off the bat. Slowly build your strength-training routine with low resistance -- you should be able to perform 12 repetitions while maintaining correct form. In addition, there's little to gain from performing more than on set of 12 reps, according to MayoClinic.com. Muscles need to repair between workouts, so wait at least a full day before training the same area again. If you're new to exercise or have a medical condition, see a doctor before starting a new program.
Nina K. is a Los Angeles-based journalist who has been published by USAToday.com, Fitday.com, Healthy Living Magazine, Organic Authority and numerous other print and web publications. She has a philosophy degree from the University of Colorado and a journalism certificate from UCLA.