Looking for a way to shape up? Keep fit? Stay limber? A diet of regular exercise can help. Different types of exercise benefit the body in different ways: some improve flexibility; some improve muscular strength. Others enhance physical endurance, and still others improve cardiovascular and respiratory efficiency.

The benefits of exercise are widely known, but the keys to maintaining an exercise program can be elusive. Unfortunately, relatively few consumers stick with their programs: basements, rec rooms, and yard sales are stocked with costly stationary cycles, treadmills, and rowing machines that have been underused, neglected, or turned into clothes hangers. Good intentions are no match for stretching, walking, lifting, swimming — or any other regular physical activity. Which exercise is best? The one you’re really going to do.

Buying fitness equipment for home workouts can represent a sizable financial commitment as well as a lifestyle change. The Federal Trade Commission advises work-out "wannabes" to exercise good judgment when evaluating advertising claims for fitness products. Before you buy, the FTC suggests you ask yourself the following questions:

What are your goals? Whether you want to build strength, increase flexibility, improve endurance, or enhance your health, look for a program that meets your personal goals. Remember that the best route to overall fitness and health is one that incorporates a variety of physical activities as part of a daily routine.

Will you really use exercise equipment? In theory, exercising at home sounds great. But if you don’t use a piece of equipment regularly, it can burn a hole in your pocket without burning off any calories. Before you buy, prove to yourself that you’re ready to stick to an ongoing fitness program. Set aside some time in your day for physical activity — and then do it.

Can exercise equipment help you spot reduce? No. No exercise device can burn fat off a particular part of your body. To lose the proverbial spare tire or trim your hips, you must combine sensible eating with regular exercise that works the whole body. The reason: Everything you eat has calories and everything you do uses calories. Your weight depends on the number of calories you eat and use each day. Increasing your daily physical activity will burn extra calories.

Can you see through outrageous claims? Exercising regularly can help you shape up. But some companies claim that you can get results by using their equipment for three or four minutes a day, three times a week. Sounds fabulous, right? But realistic? Not really. Here’s how you can spot the fantasies when you’re sizing up claims by equipment manufacturers:

• Any ads that promise "easy" or "effortless" results are false. Many ads that make big promises about the number of calories you’ll burn also may be deceptive. Indeed, some of the claims are true only for athletes who already are in top physical condition; others may not be true for anyone.
• Claims that one machine can help you burn more calories or lose weight faster than others can be tough to evaluate —especially when you can’t read the "scientific studies" mentioned in the ads. For these claims, apply two rules:
• Equipment that works the whole body, or major portions of it, probably will burn more calories than devices that work one part of the body.
• The more you use your equipment, the more calories you’ll burn. That’s why it’s important to select equipment that suits you and your lifestyle. A study might show that a different device burns more calories an hour, but if it’s uncomfortable or difficult to use, chances are it will gather dust rather than help you burn calories.

Have you checked the fine print? Look for tip-offs that getting the advertised results requires more than just using the machine. Sometimes the fine print mentions a diet or "program" that must be used in conjunction with the equipment. Even if it doesn’t, remember that diet and exercise together are much more effective for weight loss than either diet or exercise alone.

Many ads also feature dramatic testimonials or before-and-after pictures from satisfied customers. These stories may not be typical. Just because one person has had success doesn’t mean you’ll get the same results. And endorsements — whether they’re from consumers, celebrities, or star athletes — don’t mean the equipment is right for you.

Can you try the equipment before you buy? Before you buy any exercise equipment, try it out. A few minutes at a sporting goods store while you’re wearing street clothes isn’t very helpful. Test different types of equipment at a local gym or recreation center. Better still, go to the store dressed for exercise and give the equipment a full work-out.

Have you shopped around? Before you buy, check out articles in consumer or fitness magazines that rate the exercise equipment on the market. Much of the equipment advertised on television or in magazines also is available at local sporting goods, department, or discount stores. That makes it easier to shop for the best price. Don’t be fooled by companies that advertise "three easy payments of ..." or "just $49.95 a month." Before you buy any product, find out the total cost, including shipping and handling, sales tax, delivery, and set-up fees. Get the details on warranties, guarantees, and return policies: A "30-day money back guarantee" may not sound so good if you have to ante up a hefty fee to return a bulky piece of equipment you’ve bought through the mail. Check out the company’s customer service and support, too. Who can you call if the machine breaks down or you need replacement parts? Try any toll-free numbers to see whether help really is accessible.

Occasionally, you can get a great deal on a piece of fitness equipment from a second-hand store, a consignment shop, a yard sale, or the classifieds in your local newspaper. But buy wisely. Items bought second-hand usually aren’t returnable and don’t have the warranties of new equipment.