Want to win? Then train like a girl.
Physiologically men and women are pretty similar. While there are key sex differences in the physical characteristics which affect performance in strength sports, mostly this is down to differences in body composition.
Pound for pound women tend to have about 33% less total muscle mass than men (Lindle et al., 1997) with about 50% less in the upper body and 25% less in the lower body (Miller et al., 1993), largely due to the upper body's higher sensitivity to testosterone.
Some research suggests that about 97% of the strength difference between men and women is accounted for by these differences in body composition (Bishop et al., 1987) – meaning that men and women with the same amount of muscle mass should show similar performance.
But this is only half true. While men and women with similar body composition do tend to have similar absolute strength, there are a whole host of performance differences – often differences in women's favour – which persist independently of body composition. Read on to find out what these are, and how they can help you train smarter and perform better.
Muscle fiber types
Human skeletal muscles are made up of 3 different muscle fiber types, each of which is suited to a different kind of performance. In simple terms, Type 1 fibers have the least explosive power, but are the most resistant to fatigue, and recover quicker, while the inverse is true for high power, rapid fatigue Type 2B fibers. Type 2A fibers sit somewhere in the middle.
While both sexes have similar numbers of each fiber, women tend to have significantly larger Type 1 fibers than men as a proportion of total muscle area (Staron et al., 2000). Since Type 1 fibers are suited to endurance, and unlike other fiber types can use free oxygen to generate adenosine triphosphate, or ATP, to fuel muscle contractions, this means that women can perform more reps per set, and tolerate longer training sessions, compared to men of a similar strength level.
Hormones and glucose metabolism
Another factor favouring women in endurance activities is the way sex influences glucose metabolism. Muscles gain the energy needed to function through a process called glycolysis, in which glucose is broken down into a substance called pyruvate, which is then further converted to the above mentioned muscle fuel -- ATP.
One factor which limits this process is glucose uptake – how quickly the muscles replenish their depleted glucose stores. And this is where women have the edge. While men have 50-100% higher fasting blood glucose levels – meaning more fuel for rapid bursts of explosive activity – women's glucose uptake rate is up to 100% quicker than men's (Lundsgaard and Kiens, 2014), giving them the energy to train harder, for longer.
One reason for this difference in glucose metabolism is hormonal. Testosterone is often viewed as the king of sports performance, but this is an oversimplification. While T mostly accounts for men's ability to build more muscle, and therefore more absolute strength, estrogen has several underappreciated performance enhancing properties, especially when it comes to endurance.
Mitochondria – the units inside cells which are responsible for generating ATP – are packed with estrogen receptors (Liao et al., 2015). When muscle glucose is depleted, women's higher estrogen levels means more estrogen attaches to and activates receptors in muscle mitochondria – translating to their higher rate of glucose uptake and glycolysis (Klinge, 2008), and ultimately to better endurance then similarly trained men.
Despite the sex differences outlined above, it's important to reiterate that up to 97% of strength differences between men and women can be explained by differences in body composition. Generally both sexes should train in similar ways.
However, that remaining 3% can make the difference between winning and losing. To take advantage of it you could:
Do more volume close to your 1 rep max than men do. Many coaches report that women can work in the 80% and up range for longer than men, and take less time to recover.
Do more reps per set, and take less rest between sets to train your Type 1 fibres to their full capacity. In fact, do more volume in general.
Train more frequently. Women not only recover faster between sets, but also between sessions – with some research suggesting women need only a fraction of men's recovery time after high intensity training (Judge and Burke, 2010).
Focus more, or less, on explosiveness than men do. While female athletes certainly can perform explosive movements, their relative lack of Type 2A and Type 2B muscle fibres makes this a suboptimal way to grow and strengthen their existing muscle fibers. Female bodybuilders be warned. That said, women looking to boost their sports performance should include explosive, low rep resistance training (even in sports where men don't) as this can actually cause Type 2 fiber proliferation -- giving you more to work with.
- If you have a coach or a PT, ask them about this. They don't need to know all the science, but they should know how men and women's training should differ.
Bishop, P., Cureton, K. and Collins, M. (1987). Sex difference in muscular strength in equally-trained men and women. Ergonomics, 30(4), pp.675-687.
Judge, L. and Burke, J. (2010). The Effect of Recovery Time on Strength Performance Following a High-Intensity Bench Press Workout in Males and Females. International Journal of Sports Physiology and Performance, 5(2), pp.184-196.
Klinge, C. (2008). Estrogenic control of mitochondrial function and biogenesis. Journal of Cellular Biochemistry, 105(6), pp.1342-1351.
Lindle, R., Metter, E., Lynch, N., Fleg, J., Fozard, J., Tobin, J., Roy, T. and Hurley, B. (1997). Age and gender comparisons of muscle strength in 654 women and men aged 20–93 yr. Journal of Applied Physiology, 83(5), pp.1581-1587.
Miller, A., MacDougall, J., Tarnopolsky, M. and Sale, D. (1993). Gender differences in strength and muscle fiber characteristics. European Journal of Applied Physiology and Occupational Physiology, 66(3), pp.254-262.
Staron, R., Hagerman, F., Hikida, R., Murray, T., Hostler, D., Crill, M., Ragg, K. and Toma, K. (2000). Fiber Type Composition of the Vastus Lateralis Muscle of Young Men and Women. Journal of Histochemistry & Cytochemistry, 48(5), pp.623-629.