On average, women are not as strong as men in absolute terms. Women’s total-body strength is roughly 67% that of men’s, with the gap larger in the upper body than the lower body. But that headline number obscures a more interesting picture: the reasons for the gap, where it shrinks, and the areas where women actually outperform men.
How Big Is the Strength Gap?
Women’s strength typically falls in the range of 40 to 75% of men’s, depending on the muscle group being tested. The upper body shows the widest divide. In a study comparing male and female athletes, women’s bench press strength was about 41% of men’s, while their squat strength was about 43% of men’s. A review of nine studies found women’s upper-body strength averaged 55.8% of men’s, while lower-body strength averaged 71.9%.
Powerlifting world records tell a similar story. Female world records in the bench press range from about 61 to 71% of the male records across weight classes. In the squat and deadlift, women’s records reach 66 to 77% and 69 to 79% of men’s records, respectively. The gap narrows as you move from pressing movements to pulling and leg movements, but it never fully closes.
Why the Upper Body Gap Is Larger
Men carry significantly more skeletal muscle than women: about 33 kg versus 21 kg on average, which works out to 38% of body mass in men versus 31% in women. That muscle isn’t distributed evenly. The difference is about 40% in the upper body compared to 33% in the lower body. Women simply have proportionally less muscle tissue in their arms, shoulders, and chest relative to their legs and hips. This is the single largest reason women’s upper-body strength lags further behind than their lower-body strength.
What Happens at the Muscle Fiber Level
Men and women don’t just differ in how much muscle they have. They differ in what kind. A meta-analysis of muscle fiber research found that men have a greater proportion of Type II fibers, which are the fast-twitch fibers responsible for explosive power and peak force. Women have a greater proportion of Type I fibers, the slow-twitch variety built for endurance. Men’s fibers are also larger in cross-sectional area across all fiber types.
This fiber composition has real consequences. More Type II fibers means more capacity for short, powerful efforts. More Type I fibers means better sustained performance over time, which is one reason women show advantages in fatigue resistance.
Where Women Have the Edge
Women are significantly more resistant to muscle fatigue in certain muscle groups. In one study measuring how long participants could sustain a contraction at the elbow, women lasted an average of 112 seconds compared to 80 seconds for men, a 40% advantage. This difference didn’t appear at the ankle, suggesting fatigue resistance varies by muscle group rather than being a blanket female advantage.
The likely explanation ties back to fiber type and metabolism. Men tend to rely more on glycolytic energy pathways, which produce power quickly but generate fatigue-causing byproducts. Women lean more on oxidative processes, which are slower but more sustainable. If you’re comparing who can maintain effort over a longer duration rather than who can produce a single maximal effort, the picture shifts considerably in women’s favor.
How Women’s Muscles Recruit Differently
Even at the level of nerve signaling, male and female muscles operate with distinct strategies. Research on the quadriceps found that women produce force using smaller motor units (the bundles of muscle fibers controlled by a single nerve) that fire at higher rates. At low and moderate effort levels, women’s motor units fired about 7 to 8% faster than men’s. Men, by contrast, relied more on recruiting progressively larger motor units.
The end result at any given percentage of maximum effort was the same: both sexes controlled force with equal precision. Neither approach is better or worse. They’re simply different neuromuscular strategies for achieving the same task, and both sexes scaled up their recruitment in identical patterns as effort increased.
The Role of Testosterone
Testosterone is often cited as the primary driver of men’s strength advantage, and it does play a central role, but not in the simple “more testosterone equals more muscle” way most people assume. Recent cell-level research shows that male and female muscle cells respond to testosterone through entirely different molecular pathways.
In male muscle cells, testosterone activates energy metabolism pathways directly, acting as both a fuel regulator and a growth signal. In female muscle cells, testosterone triggers a broader response involving satellite cell activation, the process that repairs and builds new muscle tissue. Female cells released more growth factors and showed more proliferative signaling. Male cells bypassed those growth factors entirely, using a more direct route to stimulate protein building. The difference isn’t just quantity of hormone. It’s a fundamentally different cellular response to the same signal.
Does the Gap Shrink With Training?
One of the most striking findings in strength research is what happens when men and women follow identical training programs. A systematic review and meta-analysis found no significant difference in muscle growth between the sexes. Women built muscle at the same relative rate as men. For lower-body strength gains, the sexes were again statistically equal.
For upper-body strength, the results actually favored women. Untrained women showed larger relative gains in upper-body strength than untrained men following the same program. This makes intuitive sense: women start with less upper-body muscle, so the same training stimulus represents a bigger percentage jump from their baseline. The absolute gap remains, but the rate of improvement is equal or better.
Adjusting for Body Size
Some of the strength gap is explained by the simple fact that men are, on average, larger. When researchers adjust for body weight, the gap narrows but doesn’t disappear. Women’s upper-body strength relative to body weight has been reported at 60 to 70% of men’s. Even when researchers control for lean body mass specifically, removing the influence of body fat differences, men still produce more force per kilogram of muscle. This residual gap comes from the fiber type differences, the larger individual fiber size in men, and the different hormonal environment supporting those tissues.
The gap is real, consistent, and rooted in biology. But it coexists with areas of female advantage in endurance, fatigue resistance, and relative training response. Strength is not a single number. It depends on what you’re measuring, how long you’re measuring it, and whether you’re looking at peak output or sustained performance.