We are in the quarterfinals of that global sporting phenomenon known as the Women’s World Cup. There have been, as usual, shocks and surprises. (The United States, Canada and Brazil are out; Jamaica and Morocco ascendant.) There have been, less usual, record-breaking crowds.

What there hasn’t been, at least compared to any other WWC, is a lot of white shorts.

No white shorts as part of the England team uniform. No white shorts for New Zealand. No white shorts for Canada, France or Nigeria — all countries that wore white four years ago. No white shorts as part of the home kit for the United States for the first time since the WWC began in 1991.

“It’s period justice,” said Dr. Akilah Carter-Francique, the dean of the School of Education, Health and Human Services at Benedict College in Columbia, S.C., and the former president of the North American Society for the Sociology of Sport.

And it is the latest example of a trend that is sweeping women’s elite sports, as athletes increasingly rebel against received uniform conventions handed down over decades.

At Wimbledon earlier this summer, Elena Rybakina of Kazakhstan and Shelby Rogers of the United States were among the first competitors to wear dark shorts under their tennis whites, as the All England Club finally relaxed its all-white rules in recognition of female menstrual reality. At the EuroHockey Championship later this month, shorts will be an option for every participant as well as the traditional skorts, and the decision about what to wear will be left up to each individual player. And some track and field competitors have swapped their bikini-like “buns” for shorts and leggings in competition.

This all follows the furor of 2021 when the Norwegian handball team was fined by its governing body for wearing shorts over the mandated bikinis; the German Olympic gymnastics team competed in full-body unitards rather than tiny leotards; and the pole-vaulter Holly Bradshaw wore a onesie rather than a crop top and bikini to win her bronze — which itself came after the hoo-has generated by, well, pretty much everything Serena Williams ever wore on the tennis court, including a unitard at the French Open and a tutu at Flushing Meadows.

In the wake of Title IX, and the fight for equal access to sports, after the (ongoing) battle for pay equity in competition, comes the war for uniform equity. It’s not just about clothes. It’s about choice.

At a time when controlling women’s bodies is at the forefront of political and cultural debate, as issues of dress codes become more and more contentious in schools, companies and seats of government, the sports world may actually be the heart of the resistance.

“It’s not a moment,” said Tess Howard, a member of the English national field hockey team since 2018 and a driving force behind the changing uniform regulations in that sport, including swapping out the team’s low-cut formfitting compression tops for looser running vests. “It’s a movement.”

Shrink It and Pink It

For pretty much as long as women have been in sports, society has been conflicted about women in sports, raising issues that reflect entrenched prejudices about femininity, sexuality, power, gender and stereotype.

“Women using their bodies for their own pleasure and recreation, women using their bodies in a powerful way, should not be revolutionary in 2023,” said Lauren Fleshman, the United States national champion distance runner and author of the recent memoir “Good for a Girl.” “But it is.” And there are few examples of women glorying in the power of their bodies as viscerally clear as sports.

Uniforms in women’s sports have effectively evolved in two ways. On one hand, they were simply downsized versions of men’s styles, as in basketball and soccer. (Nike did not start making women-specific World Cup kit until 2019 and did not re-engineer the W.N.B.A. jerseys until 2021); on the other, they were designed to be expressly feminine, like tennis dresses, field hockey skorts and the highly sexualized abbreviated, bathing suit-like bras and bikinis worn by track athletes and beach volleyball players.

Either way, they were essentially tailored for men — either literally, meaning they didn’t fit female bodies correctly, or for the male gaze.

This became particularly obvious after the advent of Title IX in 1972. By the 1984 Summer Olympics in Los Angeles — the first time a women’s marathon was included in the Games — “the U.S. had the chance to show off the best female athletes in the world, in the most marketable way,” Ms. Fleshman said. Which meant “combating fears that allowing women to participate in sports equally would make them too masculine. The feminization of the uniform was a way to soften that.”

Also, it provided, as she pointed out in her book, “entertainment consolation for audiences watching ‘inferior performances.’”

It was a response, Ms. Howard said, to “the idea we had to be identifiably a woman, and the way to be identifiably a woman is through a gendered uniform.” After all, part of winning is being photographed while winning.

It’s why Sepp Blatter, then the president of FIFA, suggested in 2004 that women soccer players should wear “tighter shorts” and why there was a brief moment in 2011 when the AIBA, the boxing association, suggested that female boxers compete in … skirts.

Though both of those ideas were rejected fairly quickly, it is still true, Ms. Fleshman wrote, that “uniform guidelines mandating exposed skin and ‘formfitting’ silhouettes for only one gender have been coded into rule books across many sports. In others they have been internalized as symbols of professionalism by the women themselves.” If you grow up watching champions in buns (or “runderwear”), you think champions wear buns. If you watch winners in dresses, you think winners wear dresses.

“It’s called ‘the athletic-feminine identity paradox,’” Ms. Howard said.

And it exists, Ms. Fleshman said, “until someone asks to change it.” Until someone says, effectively, “Wait — why are we doing it this way?”

Wait. Why Are We Doing It This Way?

Wait, why are athletes wearing white shorts and wondering if spectators can tell they are menstruating instead of focusing on doing their job? Wait, why do field hockey players practice in shorts and compete in skorts (and, for that matter, wear low-cut compression tops that show off their cleavage every time they bend over)? Wait, why do men run in shorts and play volleyball in shorts and women do it in tiny bottoms that make them worry about cellulite and bulges and showing their stomachs? Wait, why are the armholes of basketball jerseys so enormous that they act like windows to the sports bra? Wait, why is the default garment the smallest garment as opposed to the most neutral garment?

Clothes are to a certain extent a form of encoded messaging between head and body. Put simply, they make you feel a certain way about yourself, and that influences how you act and perform. Or so found Hajo Adam, an organizational psychologist at the University of Bath in England, and Adam D. Galinsky in their 2012 paper, “Enclothed Cognition,” which looked at the effect white lab coats have on the wearers. Essentially, people in lab coats behaved more like doctors and paid more attention — because they dressed like doctors, which made them feel more like doctors.

The same effect is true for athletes. Just as clothes, the most intimate of tools, can make you perform better, they can have the opposite effect. Ms. Howard began studying the relationship between sports uniforms and the rate of girls dropping out of sports as part of her undergraduate dissertation at Durham University, and earlier this year published her findings in a report entitled “Practical, Professional or Patriarchal?” which included the startling data point that 70 percent of girls who dropped out of sports dropped out because of uniform and body image concerns. She called it her “aha” moment.

“It’s presented as a girls’ issue,” Ms. Howard said. “But it’s actually a systemic issue.”

Indeed, in 2020 — after allegations of gender discrimination (including one lawsuit that is ongoing) and athletes like the track and field star Allyson Felix leaving to start brands specifically tailored to women — Nike set up a female-specific athlete’s think tank to better hone their offering. In addition, now about “70 percent of the participants” in the Nike Sport Research Lab, which studies how product innovation intersects with performance are women, said Tanya Hvizdak, Nike’s global women’s sports marketing vice president. “There’s a much more concerted effort to focus on the female body; to lean into what she needs. Versus him.”

Dina Asher-Smith, the Olympic sprinter, was part of the first Nike think tank. She said she never really thought to question the practice of running in tiny bikini bottoms and a crop top until she was offered a leotard-like garment, which leaves the legs free much like buns do, but covers the torso.

“I did not realize how much I did not like having my stomach on show until I had a functional and valid option to change it, ” Ms. Asher-Smith said. “For some women empowerment is wearing a crop top and knickers, and that’s absolutely OK. But I wasn’t one of those girls, and when I was running around in the leotard prototypes testing and was confident that I wasn’t going to fall out of it, I was like, ‘Yeah, let’s go. Get this on.’”

One day, Ms. Howard said, “we’ll look back and laugh about what we used to wear.”

Pros’ Choice

“Sport is a microcosm of our larger society,” Dr. Carter-Francique said. “And the experience women are having in these spaces as it pertains to their bodies is about the tension between how they are represented, as opposed to what they do.” It is about the complications in “moving from object to subject.” It is probably not a coincidence that the revolution in professional women’s sports kit has reached critical mass in the same period that women’s rights are under threat in countries across the globe.

The fight to wear what they want is really a fight about the right to decide for oneself what it takes to succeed. That’s what Sabrina Ionescu, a guard for the Brooklyn Liberty of the W.N.B.A., realized when the team’s uniform was expanded to include shorts in different lengths — below the knee, at the knee, above the knee — and jerseys with different necklines. Having such options is, she said, “extremely important. It allows you to be who you want to be.”

And it is why the move away from white shorts in the Womens’ World Cup, which could seem so minor, is actually so meaningful. It’s what Risa Isard, Nicole Melton and Charles Macauley of the University of Massachusetts call “an act of everyday resistance.” Simply by taking the field over and over again in front of millions of eyes in green and red and blue and black, these teams normalize the concept of bodily autonomy and — yes — choice through sheer repetition. And when their fans dress up in their jerseys and shorts to pay them homage, they may internalize the same messages.

“These are women sort of drawing a line in the sand in areas where they have more control,” said Nikki Neuburger, the chief brand officer of Lululemon, which in March 2022 introduced a woman’s running shoe built on a last made from a million female foot scans (rather than a modified male shoe). They are saying, Ms. Neuburger continued: “We’re here, we’re equal. We have a voice, we have needs that have to be met. And in this space, there is actually not a great argument for why that shouldn’t be true.”