Fitness Myth No. 1: Running on a treadmill puts less stress on your knees than running on asphalt or pavement.

Fitness Myth No. 2: Doing crunches or working on an "ab machine" will get rid of belly fat.

Fitness Myth No. 3: An aerobic workout will boost your metabolism for hours after you stop working out.

Fitness Myth No. 4: Swimming is a great weight loss activity.

Fitness Myth No. 5: Yoga can help with all sorts of back pain.

Fitness Myth No. 6: If you're not working up a sweat, you're not working hard

Fitness Myth No. 7: As long as you feel OK when you're working out, you're probably not overdoing it.

Fitness Myth No. 8: Machines are a safer way to exercise because you're doing it right every time.

Fitness Myth No. 9: When it comes to working out, you've got to feel some pain if you're going to gain any benefits.