Exercise is a critical part of a healthy lifestyle, but health clubs and gyms are also home to a bulked-up trove of myths.
Fortunately, ABC News OnCall+ Wellness has called on its experts to explode some of the perennial misinformation we've all heard about exercise.
"It's important to remember, in some of these myths, that it's different for a person who's been injured as opposed to someone who's healthy and not injured," said Dr. Sherwin Ho, an orthopedic surgeon and director of the sports medicine fellowship at the University of Chicago Medical Center.
"[For] those that are injured, some of these myths are actually true, and that's where they came from."
Different people may receive different exercise advice, but it's clear that everyone can benefit from the exercise itself.
"I'm a person who believes in health at every size," said Joanne Ikeda, a nutrition education specialist at the University of California, Berkeley.
She said that even in larger people, working out can reduce the risk of chronic diseases and make them more manageable.
Further, she said, weighing more does not, by itself, mean that someone is less healthy.
"I think what's important are the metabolic indicators of fitness," Ikeda said, noting that doctors look at things like blood pressure, cholesterol level and circulation when evaluating patient health.
Fact or Myth? Crunches Will Flatten Your Stomach
Crunches alone won't flatten your stomach, because there are no exercises to reduce fat in specific areas of your body.
"Basically, you can't spot reduce -- your body decides where to store fat and a lot of that is based on your genetics," said Gerald Endress, fitness manager for the Duke Diet & Fitness Center.
The best way to get a flat stomach, then, is to burn calories to reduce fat in the first place -- crunches will simply tone areas, but won't reduce the fat there on their own.
Exercise in general will burn calories and reduce body fat overall, said Ho.
"If the majority of your fat is in your abdominal or stomach area, yeah, you'll notice a difference, but it will burn it everywhere," he said.
The myth of crunches flattening your stomach may have evolved because sometimes crunches give the appearance of reducing stomach fat.
Ho notes that crunches burn calories, so performing large numbers of them every day will contribute to weight loss, but not as effectively as cardio.
Endress said that crunches might also seem to have a stomach-flattening effect because they can tighten and strengthen the muscles that support your back, creating the appearance of a flatter stomach.
Endress said that an exercise routine to flatten the stomach might vary by person. "You basically want to pick an activity you can stay with consistently during the week."
He said he often recommends strengthening the area through Pilates, yoga and muscle training that focuses on the torso.
Fact or Myth? If You Stop Working Out, Your Muscle Turns To Fat
Muscle only turns into fat in very rare circumstances, and it never occurs in healthy people.
"They're two different types of cells," said Endress. "Muscle doesn't turn into fat and fat doesn't turn into muscle."