Have you done thousands of crunches, but still can't find your six-pack? You may be falling for a common workout myth.

Fitness instructors examined five of the top myths to help you get good information and, hopefully, a start on a new routine.

Diet Myths | No-Sweat Home Exercise | Diet/Fitness

I have to pant and sweat for a workout to count.

It can be hard to dislodge from the couch if you think you have to get really uncomfortable at the gym to lose any weight. Take heart.

"A brisk 15-minute (daily) walk ... over a year ... burns around 30,000 to 35,000 calories," according to CalorieKing.com. "Simply swapping your car for your walking shoes could mean the difference between maintaining your weight and gaining a few extra (pounds) over the year."

If you want to lose weight -- not just maintain what you have -- you still don’t need to devastate yourself. Lisa Lewis, the fitness manager at Omaha's ShapeXpress gym, uses a talk test to determine whether her clients are working hard enough to burn calories.

"My rule of thumb is, you shouldn't be able to tell the whole story or use big words. If you're speaking eloquently -- able to use the word eloquent -- you're not working out hard enough," Lewis said.

Lifting will make me bulk up.

Some women won't approach a weight room, because they're afraid they'll quickly build manly muscles that take away from their femininity. Trainers said not to worry.

"It is impossible to accidentally bulk up," said Eric Schmuecker, the fitness director at an Omaha YMCA, because only a very small percentage of women have the amount of testosterone in their systems to put on real bulk.

Schmuecker said he spends a lot of time explaining that women who do have bulk have had to work years to put it on centimeter by centimeter.

"It takes so many grams of protein and calories to maintain a certain muscle mass. Most people -- women and men -- don't eat enough to maintain that kind of physical stature," Schmuecker said.

Regular folks need about 1 gram of protein per kilogram of body weight a day, experts advise. That works out to about .4 grams per pound of body weight. Note: This story previously stated incorrectly that most people need about 1 gram of protein a day per pound of body weight.

Mr. or Ms. Universe candidates have to eat 1.5 grams of protein. I'll just work the spots that bother me.

Lewis said many of her clients at women-only ShapeXpress ask her to turn their fat into muscle -- an impossibility, since the two substances are built in a vastly different way by the body.

Spot reducing is no more realistic, she said.

"Women approach me and hold out their tummy fat (and say), 'Can you help me get rid of this?'" Lewis said. "Women especially believe in spot reduction -- 1 million crunches to no tummy. The key to losing fat is cardio exercise, total body strength training and a healthy diet. They're sick of me saying this."

And don't get too emotional over numbers on the scale.

"A better measure (is) how your clothes fit," said Shain, the one-named general manager of Fit 4 Life in Council Bluffs, Iowa, and the author of Get Fit Workbook.

"Muscle weighs more than fat. Don't pay too much attention to the scale. You may go up but lose body fat. We also measure circumference, because body fat can stay steadier longer," he said.

After the gym, I'll keep burning calories at home.

There is a misconception that you burn considerably more calories than you did in the workout itself after you stop exercising.

"Calorie expenditure is elevated for the first minute or two (after you stop exercising), but by five or six minutes, the extra expenditure is pretty small, and by 40 minutes post-exercise, it's back to where you started," William Evans of the University of Arkansas for Medical Sciences told InfoPlease.com.

The myth may have sprung from a truth: An exercise habit does help you burn more calories even when you're not exercising.

"The more you work out, the higher your metabolism, which will increase the amount of calories you burn throughout the day," Schmuecker said.

The real "after burn" comes from lifting weights, not cardio, according to Dr. Anthony Bull, an assistant professor of exercise science at Creighton University in Omaha.

"When you do weight lifting, you don't burn many calories ... but you've done microdamage and the body has to repair that. That whole process of breaking down muscle tissue and rebuilding proteins takes a little more energy," Bull said.

I can't fit regular exercise into my life, so why bother at all?

President Bill Clinton used to say his political enemies were making "perfect the enemy of the good." Couch potatoes sometimes use the same logic. But some exercise is always better than none, and you don't need a gym membership to get appreciable fitness gains.

"It takes 10 to 12 weeks of regular exercise to become fit," according to the Center for Science in the Public Interest. "But your health can improve after that first brisk walk or run."

Bull said some of the benefits – such as diabetes prevention -- only last 48 hours, which is why the government recommends 30 minutes of activity a day. But even 10 minutes a day as often as you can fit it in will build those long-term benefits, Bull said.

And, yes, taking the stairs instead of elevator, walking to the store or parking in the furthest parking spot all count toward better fitness, and toward government-issued standards of 30 minutes of exercise a day. More Links:

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