Will Weights Make Women Bulky?

We’re making enormous progress in breaking down the fear-based stigma that weights have on a woman’s physique. More and more women are embracing its benefits and the strength it provides, both physically and mentally.

We want to see the movement away from skinny, weak women gracing the cover of magazines to strong, empowered women. 

The scientific reality is that strength training is one of the smartest decisions that women can make for aesthetic goals.

It will assist in burning fat and developing muscle in areas like the butt, hamstrings, arms and abs, not to mention the empowerment that comes from physical strength.

Being physically strong is a trait we would love to see more women become comfortable with, but that’s entirely up to each woman and their goals. Be thin, be muscular, be athletic, be flabby. Whatever makes you happy as a woman is what we support.

Just don’t make decisions based on fear and bad science.

Why Weights Won’t Make You Bulky

We constantly get the question from women, “Will weights make me bulky?”

What we really want to say is, “Ladies, stop being afraid. Embrace your inner savage. Lift with the boys. Get strong, get more confident, drop the 10 pound dumbbells and ellipticals, and cut the shit already.”

But we know that’s not going to work, so today we’re going to explain why strength training will do much more for your body than your long distance runs, spin classes, hot yoga, pilates and anything else that prey on fear in their advertising.

Genetics Don’t Favor Bulk

Here’s the thing. For most of us who didn’t win the genetic lottery, our training has a very limited role in our body composition. It’s a catalyst, but not nearly as big as other factors like diet and genes from mom and dad.

While some women are definitely born with favorable predispositions to muscle composition, most women are not (nor males for that matter).

P360 member, Anna Hollenhorst. Accomplishments:

P360 member, Anna Hollenhorst. Accomplishments: 225# back squat, 190# clean, 10 strict pull-ups, 160# overhead squat. 

Take this from Bret Contreras’ 2011 article on T-Nation.

A landmark study by Hubal used 585 subjects and showed that 12 weeks of progressive dynamic exercise resulted in a shockingly wide range of responses.

The worst responders lost 2% of their muscle cross-sectional area and didn’t gain any strength whatsoever. The best responders increased muscle cross-sectional area by 59% and increased their 1RM strength by 250%. Keep in mind these individuals were subjected to the exact same training protocol.(2)

Using empirical evidence from nearly five years of oversight of hundreds of people at Performance360, we’d venture an educated assumption that perhaps 5-10% of women fall into this category of Bret’s “best responders” to growing muscle. The kind of high performing athletes who don’t need a caloric surplus diet in order to grow, who put on muscle if they look at a barbell.

These are the elite athletes, who are the fastest, strongest and whom lifts come very natural. The women you see competing on television. They get to milestones faster than most and seemingly never plateau.

There’s an overwhelming mathematical likelihood that your body is not predisposed to adding high quantities of muscle easily.

Not Enough Testosterone

Testosterone is a contributing factor to muscle growth and most women do not produce enough of it to easily facilitate muscle growth like their male counterparts, up to 16 times less than men in fact (1).

P360 Member, Skye Halliday (Membership: 18 Months)

P360 Member, Skye Halliday. Accomplishments: 50 chin-ups in 10 minutes, Level 1 Barbell Club. 

In a 1993 study by Miller using needle biopsies, it was found that women had 45, 41, 30 and 25% smaller muscle cross sectional areas for the biceps brachii, total elbow flexors, vastus lateralis and total knee extensors respectively. (3)

It was also found that women have significantly smaller percentage of Type-I muscle fibers in the arms than men, making it more challenging for women to put on size in their upper extremities.

Lastly, it was found that women have a lower proportion of their lean tissue distributed in the upper body.

All of this science adds up to difficulty adding large quanities of muscle.

Strength Training Doesn’t “Pump”

This is a huge reason why strength training improves body composition without adding mass.

In a nutshell, muscle growth is stimulated by the tearing of type-I muscle fibers in a body building format, where load is 40 – 60% load and performed for high reps in the range of 10 or more. The high reps cause the fibers to tear, fill with fluid (the “pump”) and grow larger.

Strength training is the opposite of this.

It is low rep in the range of 1 – 5 reps and targets type-II fibers, which are more geared towards athletic performance than they are for muscle growth. You’ll become stronger and faster, but often not bigger because the muscles don’t grow in the same manner as the Type-I fibers.

Your body gets stronger as a result of nueromuscular adaptation, your brain and body working together…not bigger muscles. 

Will Weights Make Women Bulky?

P360 Member, MJ Kafkas. Accomplishments: 6:02 Mile, 275# deadlift, 140# split jerk

Further, strength training does not yield lactic acid, that “burn” or build up in our muscles from high reps that cause muscular fatigue to set in.

A study by Godfrey revealed that without lactic acid, we do not see the release of exercise induced growth hormone (EIGH) in high enough amounts to trigger benefit.(5)

Building muscle without EIGH is like trying to ice skate uphill. You can try and try but you will never succeed.

In fact, competitive power lifters depend on this very science as it’s imperative these athletes get substantially stronger without actually increasing their size and weight class.

You Likely Don’t Eat Enough to “Bulk”

The fourth and most important aspect of “getting bulky” is food. Caloric intake.

For most of us, in order to grow muscle our caloric intake and protein consumption would need to be drastically higher than most women are used to. Building muscle requires us to eat in a caloric surplus, every single day, for weeks and months.

We’ve coached a lot of women on diet.

Most simply do not conusme enough calories to get bulky.

Most women who experience what they think is “bulk” upon a weight lifting program are really just carrying too much body fat because they eat like shit and don’t do any cardio.

Body fat will take up substantially more space than compact muscle. One pound of fat bulges 18 percent more than a pound of muscle. Fat occupies 1.1 liters per pound while muscle requires just .9 liters per pound.(4)

So, that bulk you often see is often contributed by a terrible diet inflating the fat cells and taking up space rather than muscle growing out of control.

After all, that’s all bulk is. Space.

If you train heavy, ignore cardio and eat like shit. Yeah, you’ll get bulky. Just as a dude would.

If you follow a healthy diet, weights will achieve many favorable outcomes for you. Not among them is becoming bulky.

As you can see from the strong women at Performance360, heavy weight training effects all women differently. Each of them are in peak physical shape and are strong, independent women.

Why Women Should Adopt Strength Training

There are some major benefits of strength training.

Better for Your Physique Than “Cardio”

Your Basal Metabolic Rate (BMR) is the amount of calories your body burns at rest, daily. With more muscle comes an increased BMR and greater caloric expenditure while we’re sitting around doing nothing. Playing Pokemon Go, posting a snap about your work commute. Just kickin’ back burnin’ cals.

Now, there is no such thing as trading fat for muscle. One does not turn into the other. But over time, a focus on building your strength will have a favorable effect on both your ability to build muscle and burn fat.

A 135 pound woman comprised of 25% body fat will have a slower metabolism than a 135 pound woman with 18% body fat.

Strength training helps accomplish this kind of recomposition.

The aesthetic aspect of muscle growth that comes with a strength training protocol is much more proportionate than targeted hypertrophy training. Because the squat is a multi-joint, total body movement it will build muscle across your entire body, whereas something isolated like a hamstring curl will target just the hamstring.

There is no comparison to the metabolic and physiological effect that a loaded back squat has in comparison to holding a warrior pose, going for a run or even a light weight goblet squat.

Too many hear “strength training” and they think that means prematurely putting 200 pounds on the bar your first week and blowing out your back.


It simply means taking your body to a straining stimulus of 70% or higher across total body, compound movements.

You really don’t even need to care about your strength to receive the physiological benefit of training it.  It’s very safe, very beneficial and very smart of you to do if you want to have less fat and a more active metabolism. Not to mention becoming a stronger and more capable human.

There are two main reasons why traditional cardio is limited when it comes to body recomposition.

First reason, it provides little to no post oxygen effect. When we’re done running, we’ve burned all of the calories we are going to burn. The thermic effect is acute to just the duration of the workout and does not carry over to effect our basal metabolic rate in any meaningful way (unless you’re sprinting).

“But I’ve lost weight with running”

No doubt. It can certainly work to shed a little bit of weight, especially for untrained folks at the onset of a program. Think about this like building up an alcohol tolerance.

If you burn 300 calories on a run and that puts you into caloric deficit for the day, chances are it can cause you to lose some weight, just not much. And you will plateau rapidly.

Second reason, the weight may occur in a way that will not favor your body composition since it provides no meaningful work on our muscle tissue, and in fact can potentially burn it.

When in an aerobic state such as running, our body has the option to pull fuel from glycogen, fat…and muscle if underfed or performed for too long.

A lot of times people think they’ve lost fat running, but when it comes to getting analysis performed it’s often muscle tissue.

An anecdote and case study on this is P360 member, Ashley (pictured below).

Recently, Ashely began incorporating weekly long runs into her routine in preparation for a half marathon.

Since she began this long distance cardio approach, she has greatly improved her cardiovascular conditioning specific to her goal, however she has maintained the exact same body fat percentage but has decreased 0.75% of her muscle mass.

1468620066909P360 Member, Ashley Geary. Accomplishments: 300# deadlift, 225# squat, 20# weighted pull-up at a bodyweight of 119 pounds.

The distance running has stripped her muscle and preserved her fat, so she quickly began incorporating strength training once more.

Carry Yourself More Confidently

Improving physical strength always carries over to other realms of life. One of the most rewarding aspects of our job is seeing hundreds of women enter our doors each week and leave mentally stronger.

They take less shit from people.

They assert themselves at work more.

They are a more confident partner in their relationships.

They rely on others less.

Women who embrace strength training often live a more confident life.

Reach Your Aesthetic Goals

We fully support women who want to perform well and look good while doing so.

No protocol better builds the female body in all the right places than strength training. If you want a great ass and a more aesthetically proportionate body, start moving heavy barbells.

Because most every barbell lift that we perform targets the legs in some capacity, the result will be a more developed, firm and stronger backside.

While looking great in a bikini and jeans is an obviously nice benefit, a stronger butt may also be tied to longevity.

Opportunity to Inspire 

Whether it be a body with a little bit of muscle on it or the feats you can perform physically, be an inspiration to other women to change their thinking. While the movement is gaining momentum each year, we still need more of you to further the cause.

It’s just flat out bad ass to turn yourself into a woman who can lift with the boys and and often run circles around them.

No two ways about it.

Julianne’s Story

Julianne has dropped 28 pounds since she began weight training and will tell you all of the ways she has been able to accomplish that.

Simultaneously, she has trained for a medaled in a local powerlifting meet, proving that strength and lean body composition do not have to be mutually exclusive.


Read all about her amazing transformation here, in How Julianne Ignored Fitness Magazines to Lose 28 Pounds.

In Conclusion

We continue to support the shift in women becoming strong and worrying less about the question, “Will weights make me bulky?”

While it’s never fun to address head on, we will always embrace that question and strive to educate on what is most likely to happen to women who undergo a program that includes strength training.

You will burn some fat. You may add some proportionate muscle. You will without a doubt improve your confidence and your life.

We’ve shared a bit about the biological factors at play that make becoming bulky very difficult for women. The vast majority of women who eat healthy and include heavy barbell strength training see their body’s accentuate in the manner they hope for. Larger, more defined glutes. Fat reduction of the midsection and strengthening of the upper body.

The great news is that with the popularity of weightlifting across the board, more and more women are embracing the physical and mental beauty of increasing their strength.

And that..is a wonderful thing.

Performance360 was founded in 2011. With two locations in Pacific Beach, P360 has three times been a finalist for Best Gym in San Diego.


  • Pacific Beach Location: 4515 Gresham Street 92109
    Crown Point Location: 2620 Ingraham Street 92109


(1) http://vo2fitness.net/blog1/2015/03/25/x-train-fitness-myths-revealed-if-a-women-trains-like-a-man-they-will-get-bulky/

(2) https://www.t-nation.com/training/truth-about-bodybuilding-genetics

(3) http://www.ncbi.nlm.nih.gov/pubmed/8477683

(4) http://athletics.ntcc.edu/index.php?module=Pagesetter&func=viewpub&tid=18&pid=52

(5) http://www.ncbi.nlm.nih.gov/pubmed/18184755