And it’s not just young women blazing new physical trails.

“In the Masters 70-plus, they just set a record for the women’s deadlift,” says exercise physiologist Stacy Sims, who teaches at Stanford University and the Auckland University of Technology in New Zealand. “Older women are demonstrating that ‘I am strong and I can do this.’”

Built to endure

Generally, discussions of “strength” have meant brute force and speed over short distances – qualities historically associated with male physiology. But stamina, recovery, resilience and adaptability are as essential to athletic performance. And in those areas, female physiology holds real advantages, experts in sports science, human physiology, and biological anthropology have found.

The myth of female fragility is relatively modern. For most of human history, women were hauling gear, tracking prey, and walking eight to 10 miles a day – often while pregnant, menstruating, nursing or carrying children (one estimate found that hunter-gatherer women covered more than 4830km in a child’s first four years of life).

That evolutionary foundation undergirds today’s feats, experts say. “Female bodies have superior fatigue resistance,” says Sophia Nimphius, pro-vice-chancellor of sport at Edith Cowan University in Perth, Australia.

In test after test, female muscles outlast men’s when doing repetitive, if lower-weight, work, according to the pioneering research of Sandra Hunter, an exercise physiologist at the University of Michigan. Hunter’s research – and others since – has shown that women’s muscles fatigue more slowly than men’s, so they can knock out more reps, more consistently. Men might start strong with heavier lifts, but when the workout gets long? Women can keep going, sometimes twice as long, or longer, outlasting even the most jacked guys.

That endurance capacity is likely because of female bodies preferentially using slow-burning fat over quickly exhausted carbohydrates, in both athletes and less sporty people, studies have shown.

In addition to using fat for staying power, fatigue-resistant slow-twitch muscle fibres are generally more common in women’s bodies (though all bodies vary in their proportion of muscle fibres according to individual genetics). This muscle type is also more efficient than fast-twitch, which is generally higher in men’s muscles. “Our muscles do more with less,” Nimphius says.

Recovery and resilience

Beyond endurance, several small studies on sprinting and heavy weightlifting have shown that women also recover from hard workouts more quickly. Slow-twitch muscles inherently have a higher capacity to recover, but the female advantage may also be explained by faster healing: a study shows two times faster muscle repair rates for female mice (though mice studies don’t always translate to humans). The reason? There’s strong evidence that estrogen reduces inflammation and supports muscle repair (one reason that Sims recommends postmenopausal women get targeted training support and recovery time).

However, some studies show that women are more prone to other kinds of sports injuries, especially certain kinds of knee and ACL injuries, but it’s not yet known whether that’s explained by biomechanical differences in bodies, hormones, or poor training. Some researchers say the greater injury rates in women are because existing research is based on men’s bodies: “Female bodies are different – I tell [women] the protocols you’re applying aren’t meant for your body,” says Sims.

Feats of bodily strength – in both ordinary women and trained athletes – are more than just purely physical. Many experts on competitive strength remark on this mental aspect of female endurance: “I do think that there is a mental grit, a resilience factor that helps women go to a place in their mind – a state that allows them to continue to push to the limit,” says Emily Kraus, director of the Female Athlete Science and Translational Research (FASTR) Program at Stanford University.

A changing future

Men have usually defined strength by what their bodies tend to be good at, but max bench presses or fastest sprint times, both of which men tend to excel at, are just a few ways to test the human body. If we instead focused on endurance, resilience, longevity and recovery, the narrative of who is “strong” would probably have a female form, many experts say.

Currently, young female athletes still don’t receive the same level of encouragement, training, and scientific attention as boys, Nimphius says. Research into girls’ and women’s health, while slowly improving, still lags – just 6% of sports and exercise research has looked exclusively at female bodies, according to a 2021 study.

Considering all the wins for women already, what would the landscape look like if we designed sports science around female physiology – rather than downsizing routines created for men? The current generation of women athletes is challenging the very architecture of athleticism. Soon, experts say, they will have better information to help female athletes understand and train, and that will be true for weekend warriors and 5k racing types as well. Ongoing and anticipated sports science studies will be “a game changer for girls and women – not just now, but in five, ten, fifteen years from now,” Kraus says. “And that’s really exciting.”

Four things women’s bodies do exceptionally well

Pain tolerance

Human bodies endure all kinds of pain – from menstrual cramps and childbirth to back injuries and broken bones. Pain is subjective, so difficult to measure, but most research agrees with your grandma – women seem to handle pain better. Athletes are pain experts, and numerous studies show that they have higher pain tolerance than non-athletes – and when you break it down by sex, the limited research shows that female athletes don’t differ from their male counterparts’ pain tolerance despite higher pain sensitivity and that women are more likely to play through injuries. This is probably due to both biology and experience, says Sophia Nimphius, pro-vice-chancellor of sport at Edith Cowan University in Perth, Australia. A 1981 study put it plainly: “Female athletes had the highest pain tolerance and threshold.”

Immunity

Among mammals, including humans, it is widely accepted that females have stronger immune systems than males. That’s due to the power of estrogen, and also of the XX chromosome carried by women but not men, which provides more variability in immune function. As the University of Minnesota evolutionary biologist Marlene Zuk wrote in a 2009 article, “There is no contest about the identity of the sicker sex – it is males, almost every time. Everyone knows that old age homes have more widows than widowers, but the disparity extends far beyond the elderly.” (There is a downside though; the majority of autoimmune disease patients are female. It’s the cost that women bear for an aggressive immune system.)

Resilience

Women’s bodies seem better built for the long haul – less wear and tear, more staying power, according to the limited research. The data on long-term exercise suggests women may also pay a lower price for physical strain. For instance, the British Heart Foundation studied the vascular condition of 300 Masters’ athletes (meaning over age 40), that included a mix of long-distance runners, cyclists, rowers and swimmers. In men, vascular ageing increased among the athletes – by some markers up to 10 years, increasing their risk of cardiovascular issues. Among the female athletes, the reverse was true, they had biologically younger vascular systems, lowering their risk of heart problems.

Longevity

Arguably, the truest test of any body is longevity. And with rare exceptions, no matter the species or culture, women live longer. That’s partly behavioural – men tend to take more risks that can kill them – but it’s also biological. Women tend to survive disease, starvation and injury at higher rates than men do. Studies have shown that the Y chromosome, which is unique to men, can degrade over time – a phenomenon known as mosaic loss of Y. This degradation has been linked to a range of health issues in men, including increased risks of heart disease and cancer.