Men are from Earth, women are from Earth, so let’s coach all people like Earthlings!
What Science Says about Training and the Sexes
By Courtney Kelly
Overview:
Total Read Time: 9 - 13 minutes
Note & Introduction (3-4 minute read)
The Science Behind Similarity: (1-2 minute read) What peer-reviewed research has to say about strength and hypertrophy gains in males and females.
Differences That DO Impact Training: (4-6 minute read) A dive into some of the physiological differences between males and females that do impact training. Topics include: Absolute Strength and Muscle Size, Aerobic Capacity, Recovery and Muscular Endurance, and Metabolic Efficiency and the Menstrual Cycle.
Big Takeaways for Coaches: (1 minute read) How coaches can apply this information to help all Earthlings reach their health and performance goals.
A Note on Language
(3-4 minute read)
Before we jump into this article, we have an important message: At Strength Ratio, we believe everyone should feel comfortable working out, and we want to support all people in achieving health and fitness goals, including members of the transgender community.
That’s why we want to be especially careful about how we use language throughout this article. We will be discussing similarities and differences between individuals historically categorized as biological females and biological males. Throughout our article, the term, “female” will refer to individuals whose reproductive system has produced eggs while the term, “male” will refer to individuals whose reproductive system has produced sperm.
Sometimes, throughout the course of this article, we will use words like, “guys” and “ladies”, but chiefly for rhetorical effect and mostly as a means of emphasizing how ridiculous societal norms around training can be.
We recognize that you, awesome reader, may have hormone profiles or physical characteristics that don’t place you in one category or another. We absolutely don’t want to minimize your training experience, and so we’ve analyzed specific physiological components, not just groups of components. Hopefully, that makes it easier for you to take what applies and leave what doesn’t.
If you feel marginalized or offended in any way by our language, please let us know! We value diversity and inclusivity, and we want to make sure all of our actions align with our values. We’re here to empower everyone, everywhere with sustainable training.
I: Introduction
We’ve all seen them. They’re plastered on the cover of fitness magazines, flexing around in bowflex commercials, parading through sportswear ads: The “fit male” and the “fit female.” From the looks of them, you figure they’re at least dissimilar and quite possibly members of separate species…heck, they might even come from different planets.
The fit male? He’s front and center. Arms crossed, muscles bulging like oatmeal that’s been left in the microwave too long, a signature misty-eyed pout-- you can’t miss him.
You might miss the fit female though. And that’s because she’s tiny compared to her counterpart. If you do catch a glimpse of her, you’ve probably noticed that she’s got her slim hands on her waif-like hips. And you’ve probably stared in wonderment at her impossibly perfect ponytail. (How can hair look that good after a workout!?)
So what are we, humble media consumers, to make of this? Naturally, we might be led to believe that fitness means something dramatically different for males and females-- that the sexes respond to physical training in distinct ways.
These beliefs are reinforced by the rhetoric we hear in our P.E. classes, the narrative we’ve been told time and time again by our teachers and parents and peers: Strength Training? Hypertrophy? Anything that has to do with lifting heavy weights? Save that for the guys. Ladies, here’s a coupla pink 2lb dumbbells. And a pair o’ running shoes.
Marketers of the fitness industry know an opportunity when they see one. Easiest way to bring in oodles of cash? Genderify your gym! Market the Pilates and HIIT and spin classes to the “ladies”, the power, speed, and strength offerings to the “dudes”.
The implicit assumption and the blatant message is: Males are the strong ones. They’re good at gaining muscle. And their primary training goals should be to get bulky and swole and jacked. Females? Sure, they can be relatively athletic, but not anywhere near as strong as guys. They’re weaker and thinner and smaller, and they should focus their efforts on staying that way by losing fat and toning, whatever that means. (Bias alert! I have a personal vendetta against this word.)
Thus we have a fitness world divided. We see treadmills and ellipticals dominated by females while weight rooms swarm with grunting males— with only one or two brave souls being willing to cross into enemy...I mean, the other sex’s territory.
On multiple levels, we think this is complete and utter (we’ll try not to curse here) codswallop. Philosophically, we believe that anybody should be able to have whatever aesthetic and athletic goals they want (so long as those goals are healthy), and anybody should be able to train the way they want to train. Male, female, non binary, trans, however you identify, you have the right to be strong or fast or swole or slender or whatever you want to be.
But! This article isn’t about philosophy (not to knock philosophy). It’s about science. It’s about what peer-reviewed research has to say about males and females and performance. And what peer reviewed research has to say is this: Don’t to buy into that “men are from Mars, women are from Venus” lunacy.
Males: You’re about to hear why you don’t have to avoid cardio like the plague and why a female gym buddy might push you more than your bro. Females: You’re going to find out that you’re great candidates for strength training, that you’re metabolic machines, and that there’s nothing biologically or physiologically preventing you from gaining strength or muscle as fast as a dude. And coaches: Get ready for some helpful tips on how to coach homo sapiens of all kinds.
II: The Science behind Similarity
(1-2 minute read)
When it comes to physiological/ biological factors that impact training, the reality is: Males and females are quite similar. Far more similar, in fact, than they are different.
This shouldn’t come as a surprise. After all, if you count up all of the body parts that males and females have, a large percentage of those components are shared between them. Only a small percentage (the percentage encompassing reproductive organs, for example) are not.
And all those shared body parts? Turns out, they gain strength and muscle at basically the same rate in females and males.
Greg Nuckols, mastermind founder of “Stronger by Science”, conducted a meta-analysis of 63 scientific studies comparing strength gains in males and females, both trained and untrained and of various ages. In his meta-analysis, he found that males “got 29.41% stronger on average” with strength training and females “got 37.42% stronger on average” with strength training.
“Wait a second!” You might be saying to yourself. “Does that mean that females gain strength faster on average than males?” To which we answer: While this is strong (hehe) evidence that females gain strength at least as fast as males, we can’t say for sure that they gain strength faster. And that’s due to some of the limitations of the studies, which you can learn more about by reading Greg’s article, “Strength Training For Women: Setting the Record Straight.”
So strength is one thing. But what about hypertrophy? Hypertrophy refers to muscle growth-- the actual size of muscles. According to popular belief, males have more testosterone, so shouldn’t they be able to grow muscles more easily than females?
Answer: Testosterone isn’t the magic muscle-growing elixir people think it is. While testosterone levels affect the amount of muscle people have before training, they actually don’t significantly impact people’s abilities to gain muscle with training.
And! Before you interject some other special characteristic males have that should allow them to gain muscle faster than females-- let me stop you there. In Greg’s meta-analysis (thank you, Greg) of 53 studies comparing hypertrophy in males and females with training, he found that males and females put on muscle at basically the same rate. During the course of his meta-analysis, he also found some studies that suggest females may actually have an edge, but more studies are needed for this to be conclusive.
III: Differences That DO Impact Training
(4-6 minute read)
Absolute Strength and Muscle Size
So, females can gain strength and muscle as fast as males (at least). Why is it, then, that males are usually bigger and stronger than females? When considering absolute strength gains and absolute hypertrophy gains, higher levels of testosterone do give males an advantage in the form of a higher baseline than females. So, although females may gain strength and hypertrophy at the same (or perhaps an even faster) rate than males with training, they begin their journey to swole a tad behind their male counterparts.
Which is fine, if you ask me, because what females lack in testosterone, they make up for in estrogen, which turns out to offer some significant advantages in the realm of training. First off, it actually has a beneficial effect on strength in females. Secondly, it contributes in a big way to metabolic health.
Aerobic Considerations
When considering markers of performance in sports that primarily involve aerobic activity, like marathon running, one important metric is speed. This is a domain in which males have a slight edge.
What does this edge translate to? With the same amount of aerobic training, males often become faster than females. One reason for this is that males are, on average, bigger than females, which means they have bigger hearts (the literal, thumping kind). They also tend to be leaner than females, and they have a slightly higher red blood cell count (due to higher testosterone). So, guys, if you have a no-cardio policy, you might want to rethink it.
Explosive Power
Here, it’s important to distinguish between strength and power because the two are often confused. Strength is the ability to move load. More strength leads to the ability to move more load. Power is the ability to move load fast. More power leads to the ability to move load faster.
To illustrate this, let’s compare powerlifting and football. Powerlifting is a sport that rewards strength (not power, despite the name). The winners of powerlifting meets are the ones that can move the heaviest loads. Doesn’t matter how fast they move it, so long as they do so within their minute time-frame, they just have to lift or squat or press the heaviest thing to beat their competition. Football, however, does reward power (in many positions). The athletes that can slam into an opponent and move that opponent somewhere fast excel in the sport.
We went over the fact that males don’t have an edge when it comes to relative strength gains. However, they do have an edge when it comes to power. Males have, on average, more Type II muscle fibers than females. Without getting into the weeds of physiology, just know that Type II muscle fibers are really good at producing explosive power.
Another advantage that males have when it comes to short, intense bursts of effort is a higher glycolytic capacity than females. Glycolytic capacity is the basically the ability to use up sugar for energy when there’s no oxygen around. Again, this is a capacity that’s relevant in a sport like football, which hinges on athletes’ ability to generate power.
Recovery and Muscular Endurance
But, females out there, don’t get discouraged about having a slight disadvantage when it comes to power output. While you may not have as many Type II muscle fibers as your male counterparts, you’ve got Type I muscle fibers in spades. And Type I muscle fibers are great at a LOT of stuff. Especially, when, as in women, they’re paired with a greater density of capillaries.
One of the things that Type I muscle fibers do better than their Type II counterparts is process glucose and fatty acids. This means, females, you don’t get as wrecked by workouts as males do (on average). You need less recovery time between sets, you need less recovery time between workouts, and when it comes to volume, you’ve got the upper hand. In fact, your greater number of Type I muscle fibers allows you to move load that’s near your max more times than males can.
Which means that females are able to, say, squat a higher percentage of their one rep maxes more times than males. And that means, guys, if you’re in a hypertrophy phase and you want a gym buddy to push you on volume, you might want to ditch your bro and find yourself a female training partner.
In general, females can tolerate a slightly higher training volume than their male counterparts. Part of this is related to the fact that females are metabolic machines. And that’s because they have few advantages when it comes to carrying out the chemical reactions of life. First, as I explained, Type I muscle fibers are more metabolically efficient than Type II fibers. This is because they’re more insulin sensitive, which means they take up more glucose (sugars) than their Type II fellows.
Secondly, estrogen does great things for metabolisms. More estrogen (but not overmuch) means more glucose sensitivity which, in turn, means that females are better at making use of sugars than males. Again, this also means females are, on average, more metabolically healthy than males.
Females are also better at storing and using fat than their male counterparts. As Greg writes in his “Sex Differences in Training and Metabolism”, “Women use more fat at any given exercise intensity than men do, meaning that, all other things being equal, they’re more resistant to fatigue.”
A Note about Menstrual Cycles
Here’s something females have to contend with that males don’t: Menstrual cycles. Hormone fluctuations can impact training, and understanding how they affect training can help females maximize their workouts.
While we don’t have the space to dive into the details of the menstrual cycle, we think they’re fascinating, and we would like to direct you to Greg’s article, “The Menstrual Cycle and Contraceptives: A Complete Guide for Athletes” because it’s very thorough and very informative and knowledge is strength, y’all.
What we do have time to discuss is this: Females, if you have regular menstrual cycles, you may notice that your training capacity differs during the first and second halves of your cycles.
The first half of the menstrual cycle, the follicular phase, begins at the start of menstruation and ends at ovulation. Females, this is when you many of you feel like BOSSES in the gym, and when you may notice that you are recovering from your workouts particularly well. You might be able to accelerate your strength and hypertrophy gains by adding more volume to your training during this time.
The second half of your cycle, the luteal phase, occurs between ovulation and the start of menstruation. The end of this phase is when many females experience premenstrual symptoms, which can include fatigue, pain, and difficulties with concentration.
Premenstrual symptoms vary significantly from person to person, so there’s no strict formula here. Some females may find it harder to recover from workouts and perform at the levels they’re accustomed to while experiencing premenstrual symptoms. Good news is: There’s evidence that exercise mitigates their severity. So don’t stop training!
IV: Big Takeaways for Coaches
(1 minute read)
So, what’s a coach to make of all this? We suggest the following four big takeaways:
You can expect your male and female athletes to make relative strength and hypertrophy gains at the same rate if they’re training the same amount.
Consider programming a little more volume for your female athletes than for your male athletes.
Consider being more aware of your female athletes’ menstrual cycles. You may want to fit in more volume during their follicular phase. This can accelerate them towards their health and performance goals.
Most importantly: Your male and female athletes really aren’t that different. Most of the significant differences among your clients will come down characteristics outside of their biological sex, like: training history, goals, personality, and genetic makeup.
There’s no reason why males can’t love HIIT and Pilates and spin classes, and there’s no reason why females can’t crush it in the weight room. Females can get jacked and strong, too, and males don’t have to be wary of cardio. We’re all Earthlings, y’all!