Strong /strôNG/ adjective: having the power to move heavy weights or perform other physically demanding tasks.
[Synonyms: muscular, brawny, strapping, sturdy, burly, heavily built, meaty, robust, athletic, tough, rugged.]
Based on Google’s top definition of the word, you can plainly see how anything strength-related has always had more of a masculine filter to it. Yes, men produce more testosterone than women. Does this mean they are superior physical beings able to achieve greater and more intense feats of strength and fitness?
Wrong. Well, sort of.
Strength can be defined in many ways. Today, we’ll be looking at it through a different lens to specifically highlight differences in strength capabilities between men and women.
Note that there’s a lot of variation with regard to how men and women metabolize sugar, produce hormones, and so on — we can’t say every single woman of precisely equal weight and training history will have precisely the same advantages over a man of the same age and size and so on and so on, et cetera, et cetera. There are a lot of factors at play here, but we do want to highlight some pretty interesting research on female athletes that a lot of people may not be aware of.
Hormones of course play a huge role in each sex’s ability to perform well in certain disciplines. However, when it comes to variability within training volume and intensity (specifically in strength sports), factors such as metabolic differences, fat storage, muscle fiber types, and of course, hormones are big players in how each gender responds to a given physical task and the recovery rates that proceeds.
In a nutshell: While men can handle heavier loads in shorter time spans (think 90%+ of their 1RM), women are more set up to perform tasks of strength over a longer period of time and for more repetitions.
“Typically, female athletes are able to handle more volume due to their absolute strength being lower [than men],” explains world record-holding powerlifter and coach, Samantha Calhoun, MS, CSCS. “The reduced load induces less stress for the same amount of volume. It is not uncommon for my female clients to perform rep maxes that inaccurately reflect what they are capable of doing for a 1 RM.”
[Read our full interview with Samantha Calhoun here!]
In other words, women and men shouldn’t use the same calculations to work out their 1-rep max because women can endure more volume.
Let’s dive into it, shall we?
Metabolism
The first major factor here is our metabolism. More specifically, how each sex goes about this process differently. While this may come as a surprise for many, women are more metabolically equipped than men to perform tasks of strength over a longer and consistent period of time. This can be measured through the rate of glucose uptake in one’s muscles as they undergo a basic strength training session. Depending on the studies you look at, while generally, men have a 50 to 100% higher rate of elevated fasting blood glucose, they also have a 30 to 50% slower rate of glucose uptake than women.(1)
Now, a quick pause for a lesson in terminology. As a key player in our metabolic process, glucose acts as fuel for muscle contraction. Without glucose, your muscles can’t do their job. Processing this fuel and turning it into usable energy for your muscles (with the help of ATP and the mitochondria) lays out the basis of glucose uptake. The rate at which this process happens will differ based on each sex’s genetic makeup.
So, let’s say for argument’s sake women generally have lower fasting blood glucose levels than men. This means they won’t have immediately have available the required energy for a heavy single as would most men. However, due to women’s quicker glucose uptake process, they’re able to perform endurance style lifting schemes better than the majority of males.
Still following? Good.
Estrogen and Strength Training
The second key player here is estrogen. You read it right—estrogen is partly responsible for women’s general abilities to handle more volume in strength training than men.
“As a coach, you can use this knowledge as a starting point when programming an athlete you may not have as much experience with,” Calhoun points out. “From there, the program can develop itself through the strengths and weaknesses of the individual athlete.”
Let’s say a female goes to perform 5 sets of 3 reps at 85% of her 1RM back squat. As she rests between each set, the process of glucose uptake kicks in to access more fuel for her muscles to use on her next set. Now, we already know the rate at which glucose uptake happens is faster than men—this is where estrogen comes into play.
All humans have estrogen receptors on our mitochondria.(2) By giving your muscles a strong stimulus, like these heavy back squats, you’ve given your metabolism the green light to recruit more energy. This energy can be found in the mitochondria and through ATP (ie. glucose uptake). As women naturally produce and possess higher levels of estrogen than most men, this abundance of estrogen is what enables the mitochondria in a female individual to rapidly intake the available hormone and immediately create the necessary energy to perform tasks of strength. This leaves them feeling energized and ready to go for their next set.
A higher demand for fuel (or glucose) means estrogen receptors on the mitochondria will be intaking as much of this hormone as possible to produce readily available energy allowing for optimal muscular contraction.(3) Estrogen may not be the strength zapper it’s been crack up to be.
This means that thanks to women’s rapid natural production of estrogen, they may achieve muscular recovery faster than men. The more demanding the volume, the higher the demand for energy production, the faster the recovery.
Men Vs Women’s Muscle Fibers
The last key player I want to touch on is our differences in muscular fibers. While women typically have about two thirds the muscle mass men do, they have a greater proportion of Type 1 muscle fibers and capillary density.(4) We’re talking around a 1 to 4 ratio of Type 1 fiber to total fiber area on most muscles. Since Type 1 muscle fibers hold more mitochondria and tend to be recruited a lot during more “endurance” activities, this allows for an increased ability to get more blood flow to the muscle and capacity to oxidize glucose for high volume workouts. Hence, women can handle their glucose better than men, making them more resistant to fatigue during strength training.
In Conclusion
To sum it up, women can access the required energy for intra-workout muscular recover faster than men. As mentioned, the major key players here include their quicker glucose uptake process (a.k.a. energy production and recruitment), higher levels of estrogen, and greater ratio of Type 1 fibers than male individuals.
“A male athlete will have a high possibility of being able to perform a true 1RM,” concludes Calhoun. “Whereas a female may hit a 3RM but might only be able to perform a single at 2.5 to 5 kilos more than her 3RM result.”
This science goes way beyond just hormones and muscle characteristics, but hopefully this can give you a good base and understanding of the hidden differences that lie beneath the surface.
So ladies, the next time your program calls to test volume of reps, load that bar up. You might be surprised at how well you’ll handle it.
References
1. Faerch K, et al. Sex differences in glucose levels: a consequence of physiology or methodological convenience? The Inter99 study. Diabetologia. 2010 May;53(5):858-65.
2. Liao TL, et al. Estrogen receptor-β in mitochondria: implications for mitochondrial bioenergetics and tumorigenesis. Ann N Y Acad Sci. 2015 Sep;1350:52-60.
3. Klinge CM. Estrogenic control of mitochondrial function and biogenesis. J Cell Biochem. 2008 Dec 15;105(6):1342-51.
4. Staron RS, et al. Fiber type composition of the vastus lateralis muscle of young men and women. J Histochem Cytochem. 2000 May;48(5):623-9.
