The 11 Biggest Fitness Myths Trainers Wish You Would Stop Believing

It's true that cardio, such as walking, running, Spinning, or jumping rope (basically anything that gets your heart rate up for an extended period of time), burns calories. It's also true that you should incorporate cardio into your weight-loss plan if you're trying to burn fat. But it's just one piece of the puzzle.

"Cardio is not the only way to burn fat," NASM-certified trainer Ashley Stewart told POPSUGAR. "This can also be accomplished through strength training." She explained that since muscle tissue burns more calories in your body than fat at rest (your body requires more energy to support muscle tissue), you will continue to burn calories if you build muscle mass.

"This energy can be taken from fat reserves," she explained. "As people mix strength training into their workout routine, their body will lean out due to the increased demand from the muscle they are building."

If you're doing endless crunches in the quest for a six-pack, it's time you change your strategy. Not only will this not give you the results you are looking for, it limits how many core muscles you're working.

"Obtaining a chiseled midsection takes more than crunches," ACSM-certified personal trainer Chavanne Scott-Hellner, owner and operator of Fitness Together, told POPSUGAR. "To achieve a flat and chiseled midsection, you must change the actual body composition by reducing fat and building up the core muscle. To make that change, it involves a strategic mix of cardiovascular workouts, core training, resistance training, and healthy diet."

So it's true what they say: abs are made in the kitchen, not the gym. For other core-strengthening exercises beyond the standard crunch, check out these ab exercises. If you're looking for a plan to follow, this four-week ab plan checks all the boxes.

Exercise is a key part of any weight-loss program. And there's no denying that cardio, HIIT, and strength training will help you burn calories and build lean muscle (which burns calories at rest). But you can exercise all you want and still gain weight. Why? It all boils down to your diet.

"Exercise alone does not burn a lot of calories in the average person," Joe Cannon, MS, NSCA-certified personal trainer and certified strength and conditioning specialist, told POPSUGAR. "The average person might only burn about 300 calories per workout, if they are lucky. This is not enough to counterbalance overeating."

So to see results, you need to really dial in your diet. To find out how many calories you need to eat for weight loss, use this formula.

You have probably heard at some point that strength training will turn your fat into muscle. While adding muscle may make it look like it's replaced the fat stores on your body, that's not exactly how it works.

"This is the equivalent of saying that you can turn any metal into gold; don't we wish!" Meghan Kennihan, NASM-certified personal trainer, told POPSUGAR. "Muscle and fat are very different types of tissue. We cannot turn one into the other." She added that the body transformation comes from building muscle through strength training and shedding fat through eating in a calorie deficit and burning calories through exercise.

Just like how fat doesn't magically turn into muscle, muscle won't turn into fat if it's not used.

"Anybody who has ever broken a bone and had a cast knows that when we stop using certain muscles, they atrophy, but our fat-storing process exists independently and is our body's way of conserving energy for future use," Rob Sulaver, CSCS, founding trainer of Rumble Boxing, told POPSUGAR. "Muscles can shrink if they're not used, and fat can be gained or lost depending on our energy surplus or deficit."

So if your six-pack abs give way to a full keg, your ab muscles haven't all of a sudden become fat; fat and muscle are two totally separate entities.

How often do you hit the foam roller before a particularly tough sweat sesh to prevent soreness? Using a foam roller is a common way to loosen tension, but it may not be the miracle tool it's touted to be.

"While foam rolling is commonly thought to help break up gnarly stuff like scar tissue so our muscles will be able to move better before training, some new research revealed that this isn't quite true," Stan Dutton, NASM-certified personal trainer and head coach at Ladder, told POPSUGAR.

"Instead of picking up a foam roller before a tough workout or to relieve muscle soreness, opt for slow, deliberate movement that helps prepare for similar exercises that you'll be doing in that day's work out," Stan explained. "For example, if you're planning on hitting some squats, start your workout with slow and controlled bodyweight or goblet squats."

If you've read through people's before-and-after weight-loss journeys on Instagram or online, you've probably read about people who lose weight first through cardio, then build muscle with strength training. This is not the best way to go about losing fat and building muscle.

"The myth of losing fat then lifting weights is simply that, a myth," NASM-certified trainer Trudie German told POPSUGAR. "A combination of moderate cardio training coupled with weight-lifting sessions will increase the amount of fat you burn during and after your workouts." It is possible to lose fat and build muscle at the same time — make sure you balance your macros and incorporate a strategic weight-lifting plan.

How many exercise classes have you taken where you do dozens of reps with light-pound weights in an effort to "lengthen" and "tone" your muscles? Or been told that you should only do cardio if you want to lose weight? Either of these probably won't help you achieve the results you are looking for.

"If you only did cardio, then both muscle and fat would be burned for fuel," Meghan said. You want lose fat and gain muscle. "Women that only concentrate on cardio will have a very hard time achieving the look that they want. As far as the lifting of very light weights, this is just more nonsense. Muscle responds to resistance and if the resistance is too light, then there will be no reason for the body to change."

No matter how cute those pink-coated two-pound dumbbells at the gym are, they probably aren't doing you any favors.

If you've ever heard a fitness instructor promise during a tough class that you can go enjoy bottomless brunch after a workout or you've burned enough calories to make up for Thanksgiving dinner, then he or she was straight-up lying to you (not to mention that you shouldn't feel like you have to "earn" your food).

"Nutrition really is 80 percent of weight loss," Alysa Boan, NASM-certified personal trainer at FitnessTrainer.com and RealFitnessMaven, told POPSUGAR. "You can do everything right in the gym but if you do not have a well-rounded meal plan, you will not lose weight. Recovery time, sleep, hydration, and proper nutrition are all just as important as your time in the gym. It all works together, so give everything the same value."

That's not to say you can't enjoy your favorite calorie-dense foods and treats every once in a while; just don't expect to see progress if 90 percent of your diet is processed junk food.

Just like how endless crunches won't give you a six-pack, doing thousands of bicep curls won't automatically make you lose arm fat and lunges won't do anything to target the fat on your thighs.

"Simply put, you cannot spot-reduce pounds from any given region on your body," Corey Phelps, NASM-certified trainer, explained. "Just as you cannot influence where your body stores dreaded excess fat when it packs it on, you can't control where your metabolism opts to pull from when it taps into fat stores, which incidentally tends not to be from the region we gain it in the first place. When it comes to burning fat, a total bodyweight lifting program and clean-eating plan are your best bet."

You need to lose fat overall to see progress on any specific body part. This requires eating in a healthy calorie deficit and balancing cardio and strength training.

Many women tend to stick to lighter weights or avoid strength training altogether for fear of looking "bulky" and being too muscular. This is an age-old myth that needs to die.

"No amount of weight lifted will make a woman look bulky and manly!" Trudie said. "Women simply do not have enough testosterone to accomplish this. Lifting weights will increase lean muscle mass and reduce your body fat percentage to reveal a toned physique. Weightlifting has also been proven to increase bone strength and reduce the risk of osteoporosis."

So don't be afraid of the weight room — here's a four-week plan to get you started.