7 Women’s Fitness Myths Debunked With Science

Learn about the popular fitness myths debunked for women.

What you’ll learn here

Table Of Contents

With so much misinformation on how females should train, it can be a nightmare for any woman trying to get fitter. Let’s tackle them right now and get these popular fitness myths debunked.

For example, ‘strength-training will turn you into a she-hulk,’ ‘sit-ups equal ripped abs,’ and ‘cardio burns the most calories’, are undoubtedly misconceptions we buy into. 

If you’re looking for solid proof, just flip through any women’s fitness magazine. 

You’d be hard-pressed to read 3 pages of content without coming across an image of small, pink dumbbells. 

Spoiler: that model on the cover didn’t get her tight, ‘toned’ body from spending hours on the treadmill! 

If you genuinely want to achieve your fitness goals in the most time-efficient way, you’ll need to separate fact from fiction and get these female fitness myths debunked once and for all.

#1: Lifting weights will make women ‘bulky’

Of all the female fitness myths out there, this is probably the most rampant one.

Fortunately thought, it’s simply not true! 

Yes, any woman who lifts weights regularly will get progressively stronger. But that doesn’t mean she’ll be packing on muscles so aggressively she ends up looking like The Rock. 

Women don’t produce as much testosterone as men

One of the most common fitness myths debunked is that women will look manly after lifting weights.

Women produce just a fraction of the anabolic (aka muscle-building) hormone, testosterone, that men do (1, 2, 3). 

Even professional female bodybuilders with years of lifting experience can’t build the sheer mass you sometimes see on their male counterparts. 

Of course, some women choose to make up for that with steroids (testosterone or anabolic substances). 

Doing so will super-enhance their muscular development. But you don’t have to worry. This is well outside what you can do with your body naturally. 

You’ll need to eat in a calorie surplus intentionally

Also, keep in mind that you’d need to intentionally increase your calorie-intake to (significantly) bulk up your body.

I mean, you can’t expect to lose weight just from working out alone, right? A calorie deficit is the most significant piece of the weight-loss puzzle – and you need to eat right for that to happen.

Well, the same goes for building muscle.

Gaining lots of muscle mass comes from a combination of strength training with progressive overload and being in a calorie surplus. 

If you’re not eating more calories than you expend in a day, you probably won’t pack on significant muscle mass. Yes, that’s even if you’re heading to the gym five days a week (4, 5). 

And this is especially so if you’re already relatively lean. 

So, you don’t have to worry about packing on as much muscle as a professional bodybuilder. It’s not something that happens by accident! 

It actually requires a crazy amount of hard work, consistency, and discipline in all aspects of fitness and nutrition.

Definitely one of the easiest – but most impactful – female fitness myths debunked.


Putting on significant muscle mass requires intention and a calorie surplus. It doesn’t just happen from you touching a barbell in the gym.

#2: Lifting light weights for high reps gets me ‘toned’

You’ve definitely heard this before: women need to lift light weights with high reps to ‘tone’ their muscles.

That’s why you see females balking at the idea of lifting anything heavier than 5 kg – because they’re afraid of putting on too much muscle mass.

But guess what?

There’s really no such thing as ‘toning.’ Regardless of whether you train with high reps and light weights or low reps with heavy weights, your muscles are going to get bigger (6).

Instead of thinking about ‘toning,’ you should instead focus on putting on muscle while losing body fat at the same time.

Lifting heavy is a more effective way of building muscle

Since you’re going to put on muscle mass regardless of whether you’re training with:

  • Light weights and high reps OR
  • Heavy weights and low reps

Does that mean you can choose either, so long as you push close to failure?

Well, not exactly. To be more specific, you want to avoid going beyond 30 reps for any one exercise. Just think about it: 30 reps is going to extend your workout time significantly. Not fun.

And perhaps most importantly, research shows clear diminishing returns on muscle growth beyond 30 reps.

That’s because CNS fatigue will set in and you’ll reach failure in a set before you even achieve full motor unit recruitment of that muscle group (7, 8). That means later reps in your workout will be less productive.

So, what for put yourself through an extended workout session when there are no benefits?

Optimal set and rep range 

Since we’ve already established that you won’t end up looking like a she-hulk unless you eat massive amounts of food or take steroids, let’s now discuss the set and rep range you should use.

Here’s something that might surprise you. When you’re just starting in the gym, you don’t need to train any differently from men. 

Look, the American College of Sports Medicine doesn’t differentiate between sexes in their strength training recommendation (9). So, why should we?

Rep range is non-gender specific

In both men and women, the rep ranges for specific training goals are as follows:

  • Strength training (for strength gains)
    • Rep range: 2 to 6
    • Set range: 4 to 6
  • Hypertrophy training (for muscle gains)
    • Rep range: 6 to 12
    • Set range: 3 to 5

You’re going to see muscle growth with both training goals, especially so if you’re an inexperienced lifter (newbie gains!). 

Admittedly, when you get more experienced, you may need to train a little differently from men (10, 11, 12, 13, 14, 15). 

For example, even when women and men with the same strength level are compared, we’re more resistant to fatigue! That means for females looking to maximize their muscle growth potential, we should generally do more reps at a given intensity than men.

But assuming that you’re new to the gym, you don’t need to fuss over the specifics at this point.  

One of the most helpful fitness myths debunked, right? No more crazy high reps.


  • If you want to ‘tone,’ what you mean is you want to gain some muscle mass. That means you’re going to have to lift heavy.
  • You don’t need to train differently from men, especially if you’re just starting in the gym.

#3: I need to eat less protein than men when strength training

Admittedly, of all female fitness myths, this particular one sounds the most valid and reasonable.

That’s because nearly all of the research relating to protein synthesis after strength training is done with male subjects, making this one of the trickier fitness myths to debunk.

Protein intake requirement scales with lean muscle mass

But recent research shows that female lifters’ protein needs, when expressed per kg of muscle mass, are virtually identical to that of male lifters’ (16). 

That’s because protein intake requirements scale with fat-free mass. The more muscle mass you have, the more protein you’d need to consume. 

So – regardless of gender, people with more lean muscle mass will need to consume more protein.

Hopefully, you can now see that this myth is kind of a half-truth. 

Men are generally leaner than women at the same bodyweight, which then translates to them (naturally) having slightly higher protein requirements (17). 

This point is worth reiterating: it’s just not because they’re men, though. 

When we have a man and woman with the same body weight and body fat percentage, their protein requirements will be identical. 

And what will that be?

Female lifters’ protein intake requirement

You must be wondering just how much protein women should eat daily. So, here’s a quick summary (18):

  • Overweight or obese: 1.2–1.5 g / kg
  • A healthy weight, active, and trying to lose weight: 1.8-2.7 g / kg
  • A healthy weight, active, and trying to gain muscle: 1.4–2.4 g / kg
  • Experienced lifter on a bulk: 3.3 g / kg


  • Protein-intake requirements scale with fat-free mass.
  • Anyone, regardless of gender, with the same amount of fat-free mass and lifestyle as you will share the same protein intake requirements.

#4: I’ll get hurt if I lift heavy weights

You might have cringed with fear when you chanced upon some of the ‘gym fails’ videos circulating on social media. 

There are grown-ass men fainting after a heavy lift. And shoulders dislocating from an ill-executed shoulder press. Not to mention, total collapsing without a squat rack in place.

Or even more hardcore: nose spurting blood from a really heavy lift. Google ‘Mikhail Shivlyakov deadlifts’ if you can’t stop thinking about it.

For now, this is going to be one of the most important fitness myths debunked.

Strength training is relatively safer compared to many other sports

Here’s the thing though. In reality, you’re just as likely (if not more so) to get hurt doing other physical activities (19). 

Debunking the myth that strength training is more dangerous than other sports is key to changing women's mindset towards weight training.

A study in the Journal of Strength & Conditioning Research analyzed the injury rates – expressed in terms of injuries per 100 hours of participation – across multiple sports, including strength training, soccer, Olympic weightlifting, and more. 

Guess what it found? It’s statistically more likely for an injury to occur per 100 hours of soccer, in comparison to either strength training or Olympic weightlifting (20)!

Interestingly, strength training is also regularly used to supplement an athlete’s sport-specific regimen to help reduce the risk of sports-related injuries (21, 22)!

Injuries are best prevented with proper exercise execution

That said, though, while lifting weights is generally safe, injuries can and do happen. 

Women can get hurt lifting weights. But so can men.

Attempting to deadlift or squat under heavy load without proper form is a recipe for disaster.

That is why, if you’re not confident of your ability to properly execute an exercise, seek out a qualified professional to learn proper exercise technique. 

You can then ensure you’re going through the proper progression for each lift. 

With the ability to focus on both quality movement and form, you’d be building a foundation of strength to work towards for the long-term.

Ultimately, as long as you’re performing the exercises correctly, adding in some form of strength training is highly beneficial for females (23, 24, 25, 26, 27, 28, 29, 30, 31). 

Especially when it comes from an injury-prevention standpoint. 

Start slow. Master your form, and you will progress faster than you’d have thought possible.


So long as you’re performing the lifts correctly, strength training is a relatively safe sport.

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#5: Weight machines are better than free weights

If you’re new to the gym, it’s understandable why you’d gravitate toward the machines section.

The free weights area is typically full of big, grunting men, which can be intimidating. 

Besides, machines give you the same results as free weights and are safer – right? 

Well, not exactly. 

The two options do primarily the same thing. But there are noticeable differences when it comes to how your body maneuvers. 

Machines are fixed in place and only move in specific, pre-set directions. Free weights, on the other hand, can be moved in any way you choose. Thus explaining the word ‘free.’

A good example is barbell squat (free weights) compared to leg press (machine).

Free weights activate more muscles 

The most significant difference between machines and free weights is the number of muscles used (32, 33). 

Free weights force you to activate more muscles to stabilize the weight, whereas weight machines can help you with the movement by keeping your body strictly in place.

Does this then mean that there’s no place in your training plan for weight machines? No. Of course not. 

Weight machines offer unique benefits

Machines complement free weights in your training, not replace them.

There are some advantages that weight machines has to offer over free weights:

  • Allows for greater targeting of a muscle group – The lack of other muscles used with weight machine training isn’t necessarily a bad thing. Let’s say after a round of squats, your legs, and all the related stabilizer muscles are a bit fatigued. But you still want to work your quads more. Well, you can do so with the leg extension machine without having to use those sore stabilizer muscles!
  • Teaches you the mechanics of a particular lift – If you’re new to a movement, a machine is a great start and can help in learning proper mechanics. You’ll also get a better idea of where you should feel the exercise working. For example, if you’re training your glutes, the machine hip abduction is much simpler to learn than the cable hip abduction.
  • Serves as an accessory for bigger lifts – Another major perk of training with weight machines is that since your range of motion is fixed, you’re able to lift more weight. This then gets you used to handling heavier weights over time, which can help with bigger lifts like squats, deadlifts, and overhead presses.

An ideal training program will incorporate both free weights and machines to work more overall muscle and improve coordination.


  • Free weights recruit more muscle groups (stabilizer muscles) than exercise machines and are better for long-term, functional muscle growth.
  • Nonetheless, weight machines can offer unique benefits, like the learning of proper movement mechanics. 
  • Ultimately, you should incorporate both free weights and machines in your training program for the best of both worlds.

#6: Cardio will help me lose fat faster

You can definitely burn calories with cardio and that contributes to creating a calorie deficit needed for losing fat.

Cardio burns more calories per hour than strength training

According to the Compendium of Physical Activities, in which researchers examine how many calories individuals burn during various activities, cardio triumphs strength training (34).

Take a look at the numbers provided:

  • If you were to run at a pace of 6 miles per hour, you’d burn around 365 calories in 30 minutes.
  • If you did strength training for the same amount of time, you might only burn around 130 to 220 calories. 

Given that each cardio session helps you burn more calories than strength for about the same amount of effort, cardio is better for weight loss, right?

Well, not really. 

Strength training burns more calories in the long-term

As previously discussed, strength training is more effective than cardio at building lean muscle mass, which then basically serves as a calorie-burning powerhouse in the body.

Muscle – the significant contributor to lean body mass – burns more calories at rest than fat mass (35, 36, 37). 

And this means that if you want to increase your basal metabolic rate (how many calories you burn at rest), you’ll want to focus on building muscle. 

Besides, strength training will give you a more aesthetically-pleasing overall body transformation than if you just lost weight doing cardio. 

Here’s more proof that ‘cardio will lose fat faster’ deserves a spot, right up there with other popular fitness myths.

Ever noticed someone who’s lost 20 kg but still looks somewhat ‘soft?’ They’ve probably lost all that weight (along with precious muscle mass) through hours and hours of cardio. There’s significant fat-loss, yes, but their muscles aren’t ‘toned’.

Certainly one of the most impactful fitness myths debunked, isn’t it?


Cardio burns more calories per session. But strength training helps you build lean muscle, which actually burns more calories long-term. Besides, strength training will give you a more aesthetically-pleasing overall body transformation.

#7: Muscle will simply turn to fat when I stop working out

How do I put this? 

When it comes to fitness myths, this is as ridiculous as it gets.

Saying that muscle will turn into fat is about as valid as saying that gold will turn into silver. It’s simply not possible!

Muscle cannot turn into fat; neither can fat into muscle 

Through a combination of a challenging strength training program, proper nutrition, and adequate recovery periods, your muscles will grow in size via a process called hypertrophy. 

But when you stop lifting, the reverse occurs. This process is then called atrophy, where your muscle simply becomes smaller.

Muscle and fat are two completely different types of tissue. They cannot convert directly into each other (38)!

Look, muscle fibers don’t magically turn into fat cells. They simply shrink when you don’t use them.

Stop working out, and you’re likely to go into a calorie surplus 

But as you may have noticed, people who’ve stopped going to the gym do tend to end up looking heavier than they did before. 

Why’s that?

Well, obviously, if you were to stop exercising, you’d end up burning fewer calories in a single day than before. 

Coupled with the fact that you’re probably less strict with the foods that you’re eating, you’re then likely to be in a calorie surplus

Muscles don't turn to fats when you stop working out. You simply start to burn fewer calories and gain weight as a result.

And we all know what that means: weight gain (39, 40, 41, 42, 43, 44).

What may have once been a firm muscle then feels jiggly and flabby. 

But that’s a sign of a change in body composition (more fat, less muscle) – instead of one kind of fiber type being converted into another. 


Muscle cannot turn into fats – they’re two completely different types of tissue. But you will certainly lose muscle and gain fat if you stop working out and maintain a calorie surplus.

Fitness myths debunked: don’t let them keep you from achieving your goals

Improving your body composition (‘tone up’ while losing fat) doesn’t need to be complicated. 

It can be straightforward – especially with these fitness myths debunked and out of the way. 

Here are the few things you need to do:

  • Follow a training plan that incorporates both cardio and strength training.
  • Mix in a variety of free weights and weight machines for better overall muscle growth.
  • Eat in a slight calorie deficit, with sufficient protein intake. 

Remember, as with all things, consistency and sustainability are the biggest predictors of success. 

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