It happened about 10 minutes into a Crystal Palace v Lewes match. There was a hum of excitement in the Dripping Pan, Lewes FC’s football stadium. Ashlee Hincks ran down the wing, received the ball and went to cross it to a teammate. She planted one foot down and prepared to strike the ball with her other foot. But her boot got stuck in the grass; her body kept turning. “Everyone says they hear a pop or a crack. I heard a crack,” she says now. The pain was severe, and Hincks had to be carried off the pitch. She sat in the ambulance praying it was a dislocated kneecap.

It was 8 September 2019. Hincks, then 30, was a striker for Crystal Palace. She had scored more than 25 goals since she had arrived from Millwall Lionesses the year before and had been named player of the season. But now what she dreaded most had happened: she had torn her anterior cruciate ligament (ACL).

For complex, long-misunderstood reasons, women suffer this injury far more often than men. It upended the Women’s World Cup last year when two of England’s star players, Leah Williamson and Beth Mead, were out with torn ACLs. England weren’t alone. Research by @aclwfc, the fan-led resource on ACL injuries, showed that 25-30 players globally missed the tournament, including Ballon d’Or nominee Vivianne Miedema. At the start of this season – the Women’s Super League (WSL) returns next weekend – the ACL injury list includes Australia and Chelsea striker Sam Kerr; USA and Chelsea striker Mia Fishel; Arsenal midfielder Victoria Pelova; Scotland forward Fiona Brown (for a fourth time); and AC Milan and Scotland midfielder Christy Grimshaw.

Players know what it means: their career is at stake. For a European champion this is bad news. But the growth in the number of grassroots players means the issue is becoming more urgent. Almost 1,500 new teams were created after the Lionesses won the Euros in 2022, according to England Football. More than 1,000 new female players joined Surrey FA alone. And now these women are tearing their ACLs in alarming numbers.

“There’s no support for injured women. They’re completely on their own,” says Emma Eaton, football development officer (female lead) for Surrey FA, which represents around 8,500 women and girls in grassroots teams. “If you’re a nurse, how do you do your shifts? If you have kids, how do you drive them to school?”

The big question is, why is this happening to so many female players? The quest for answers stretches from second-rate pitches and ill-fitting boots to misogyny in medicine and narrow attitudes to women’s bodies. In other words, in a field dominated by men, torn ACLs are “not just about football”, says Dr Katrine Okholm Kryger, associate professor in sports rehabilitation, St Mary’s University, Twickenham. “They’re about equality.”

* * *

The anterior cruciate ligamentis a 2.5cm band that holds the lower and upper leg together. It runs deep within the knee joint and tends to blow when doing sports that involve sudden stops and changes in direction. For the ACL, pivoting is high stress: the shin bone goes one way; the thigh bone another.

“We call it the celebrity ligament,” says Ros Cooke, physiotherapist and lecturer at University College London. “It gets all the headlines.” There are very few female, upper-level sports Cooke hasn’t been involved in during her 20-year career. She spent six years with the England netball team and has worked with the Lionesses. “ACL injuries have always been there,” she says – in netball, hockey – but “at this moment, we seem to be having a cluster in women’s football”.

This summer, @aclwfc recorded 435 ACL injuries in top-tier leagues around the world since January 2022, including at least 94 players so far this year. “That’s scratching the surface,” says Hincks, who now plays for the third tier club AFC Wimbledon Women. Six players there have ruptured their ACLs since she joined in 2021: “I could probably tell you 50-plus who’ve done it. They’re just not accurately recorded anywhere.”

As sports injuries go, a blown ACL is horrible. Your knee feels loose, as if it might buckle if you put weight on it. Solving it typically involves a one-to-two-hour operation to reconstruct it with a tendon “harvested” from elsewhere – usually a hamstring. A return to peak performance can take 18 months to two years; a lifetime for an elite player. Even after a full recovery, the knee is never 100% and there can be a risk of osteoarthritis later.

The injury first surfaced as a problem nearly three decades ago, with studies on college athletes in America. Female footballers were twice as likely to have a “contact” ACL injury – where a player gets kicked, say, or tackled – than male footballers, and three times more likely to suffer a non-contact ACL injury. This is where players suddenly collapse on the pitch, as Hincks did. The injury rate has remained unchanged; what has changed is the number of women on the pitch. “We have more women playing, hence more ACL injuries,” Cooke says.

Broadly, the studies on why so many women sustain these career-changing injuries fall into two categories, focusing on intrinsic factors (anatomy, hormones, genetics) or extrinsic (weather conditions, playing surface). But, according to Sheree Bekker, an expert in sports injury prevention, “hips and hormones” has been the prevailing hypothesis. Around seven years ago, Bekker, who teaches at Bath University, and collaborators Stephanie Coen, a health geographer from Nottingham University, and Joanne Parsons, a specialist in rehabilitation sciences at the University of Manitoba, were swapping messages about the spate of ACL injuries. “There was a lot of talk about how women’s bodies were unfit for sport,” Bekker says. “We flipped the script. Rather than saying women’s bodies are weak, we asked, what is making women’s bodies weaker or more fragile?” Their investigation, Anterior Cruciate Ligament Injury: Towards a Gendered Environmental Approach, recently won two prizes from research institutes. Bekker does not claim the gendered environment is the only story. But she believes, and others back her up, that it’s hugely significant.

“We have literature from other sports, such as ballet, where ACL injury numbers are the same in women and men because they go to the same schools and train in the same environment. But if we look at sports such as football and rugby, where what we offer each gender is very different, you see a disparity,” Okholm Kryger says.

* * *

Karen Farley lives in a village outside Newmarket in Suffolk with her wife and children. In the back garden is a cabin filled with football memorabilia. Farley, 54, earned 11 caps for England between 1994 and 1996, including one for their first appearance at the official Women’s World Cup in 1995, where she scored two goals against Nigeria. Framed on the wall is her England shirt: a man’s XL. “We got the hand-me-downs,” she says. It was a “defender’s dream – a big, baggy shirt flapping in front of you. Just grab hold of it and pull them back.”

Farley grew up in Ashford, Kent, and started out playing for Ashford Town Ladies. Everyone else was in their 20s; she was 13. Her football boots were from Woolworths. Three years later she left school, moved to London and joined the Millwall Lionesses. The manager of a team in Sweden had heard of her growing reputation and summoned her for a trial. “They said they wanted me,” she recalls. “I came home, gave in my notice – I was working for Bupa in the claims department – packed everything up and got on the aeroplane.”

She spent five seasons at Hammarby, a first-tier, professional football club in the heart of Stockholm, but her biggest pride was playing for England. And then, in 1996, at the age of 25, she jumped up for a header in a league game for Hammarby and, as she landed and tried to turn, her studs stuck in the ground. She tore her ACL. Farley’s brief career with England came to a sudden end. “Eight goals in 11 games. Then she was gone,” writes Jean Williams in Legendary Lionesses.

“I just disappeared,” Farley says. “I don’t remember ever getting a call from anyone from England to check how it was going. I was a prolific goal scorer, yet it was just, oh, that’s her done. They couldn’t invest in players. They didn’t have the funding. As soon as you weren’t fit, you were gone.” She pauses. “Bitterly disappointing.”

Farley had surgery and, after 18 months in recovery, returned to Hammarby. But, one season later, the injury happened again. She retired soon after and moved back to England. Even now, her knee still aches. “There’s no stability. I started trying to play with a veterans team, did a couple of training sessions and had to stop. It’s impossible to run properly, to sprint, change direction.”

Why does she think it happened? “We didn’t do the strength training needed. We didn’t have access to gyms. We were all working full-time. Our boots, kit – all men’s. Nothing was designed for women.” She sounds more sad than angry. “But then we didn’t expect anything different.”

* * *

Women have been marginalised in football almost from the start. The FA banned women’s teams in 1921, stating that the game was “quite unsuitable for females and should not be encouraged”. Medical opinion supported the ban. Football was “too much for a woman’s physical frame”, Dr Mary Scharlieb, a well-known gynaecologist, told the Pall Mall Gazette. Eustace Miles, a writer and real tennis player, agreed. “Kicking is too jerky a movement for women … just as the frame of a woman is more rounded than a man’s, her movements should be more rounded.”

The ban was finally lifted 50 years later, in 1971. But this doesn’t mean women no longer face stigma about the vulnerability of their bodies. On the contrary, Bekker says: “Even in sports medicine, sports science literature, these assumptions underpin thinking about ACL injury.”

A classic example is hormones. Dr Jackie Whittaker is a researcher in the department of physical therapy at the University of British Columbia. Last February, after she presented a paper at the Scandinavian sports medicine congress in Copenhagen, several mothers of young sporty daughters came to confide their worries. “I’ve had many reports of coaches asking prepubertal females to take the contraceptive pill to protect themselves from an ACL tear,” she says. “Basically, coaches are suggesting a medication that has a very important role in reproductive health to young girls who haven’t had a period yet and may experience side-effects on their bone health later in life.”

How did this happen? Why is a pill that suppresses ovulation being used to protect girls’ knees? In 1998, a study published in the American Journal of Sports Medicine linked the menstrual cycle with an increase in non-contact ACL injuries. These, the study concluded, were more likely in the “ovulatory phase of the cycle”, when the ovaries release new eggs, which is a time when the luteinizing hormone surges and ligaments become slightly more lax and stretchy. It seemed to be a breakthrough insight. Yet to this day, many critics argue that the data is inconclusive. “If you were really at higher risk of injury, you would see women breaking down everywhere: knees, ankles, hips,” Okholm Kryger says. “We don’t see that. There is no direct link between hormones and your ACL, more than any other ligament in the body. It’s a very simplified way of thinking.”

But the message was so memorable, it stuck. The idea is now ingrained that periods are a risk factor. Most elite teams have menstrual cycle monitoring tools. “Are you on your period?” is the first question physiotherapists ask when players are taken off the pitch, according to Okholm Kryger, who has interviewed many WSL players. Most of the players I spoke to mentioned their period as a possible reason why they had torn their ACL.

But there may be a much more material cause of these injuries: the boots. In spring 2022, Okholm Kryger set off round Europe with a 3D foot scanner. Researching for her PhD in men’s football boots, she found most for men and women are based on the feet of a generic white male, UK size eight. “That’s manufacturers’ test model and they simply scale up or down,” she says. The presumption is that what’s male is universal; it fits all. But Okholm Kryger believes this presumption is unsound, harmful even. Men are heavier than women and interact with the ground differently. They need studs with more grip to keep them from slipping. “Women are lighter, we don’t run as fast and don’t have the same muscle mass to push off, so we need less traction,” she says. In other words, women are at greater risk of their studs sticking in the ground, and in the context of ACL injuries, this can be disastrous. “Every surface will be different, and manufacturers have tried to compensate, but no one has ever tested that, say, a soft ground boot is optimal for women on soft ground.”

Okholm Kryger decided to gather her own data. Working with the Women’s High Performance Advisory Group – research arm of the European Club Association (ECA) – she scanned the feet of nearly 250 elite female football players from leading European clubs and asked them for feedback on their boots. Her research showed that women have a wider forefoot, relative to length, a higher arch and a heel shape different from that of men. She discovered that 82% of the players had daily pain or discomfort. Some had taken to cutting a hole in the back of their boots to make them more comfortable.

Last June, the ECA and Okholm Kryger handed their findings to manufacturers. “They can now design football boots based on women’s feet,” she says.

Just before last summer’s Women’s World Cup, Nike launched the Phantom Luna, “the most innovative and researched women’s-led football design in our history”, according to the blurb. Here was a football boot designed and engineered around “her needs”. Yet which high-profile player did Nike choose to promote it? Kevin De Bruyne, midfielder for Manchester City and the Belgium national team. The Phantom Luna was in fact unisex.

“We’re being fed the lie that unisex is fine for football, but if we go running, we’re told we must have women’s shoes,” says Laura Youngson, CEO of Ida sports, a UK-based company that makes women’s football boots stocked in leading outlets in the US, where more women play football. Nike, Adidas and Puma still dominate the market, she says. The problem, she believes, is that big brands are beholden to shareholders and women’s sport doesn’t make as much money as the men’s game.

* * *

Grace Laverick, 22, ruptured her ACL playing for the Millwall Lionesses against Margate Women last October. The Lionesses were winning 10-0 (by the final whistle it would be 13-0) when Laverick received the ball and turned to avoid a tackle. She remembers the noise: “Like a gunshot. The pain followed. I just screamed. My dad jumped the fence and ran across the pitch. He knew straight away. I saw them bring a stretcher. I thought, I’m not getting on that; too embarrassing. So I got piggybacked across the pitch.”

She set up a GoFundMe page to raise £7,500 – the cost of private surgery: “The waiting list on the NHS was a year. I wanted to get it done as quickly as possible.” She asked the men’s club if they could donate. “No easy way of saying this,” stated the reply on WhatsApp, “but the club gets inundated with fundraiser requests & any that don’t directly feed into a charity go against their policy on promoting them … ”

“But Millwall fans were amazing,” she says. “One man donated money and two weeks later he said, ‘I’ve just been paid, here’s some more.’ He donated £150.” She eventually raised just over £5,300. Her parents covered the rest, topped up with her savings. Laverick had just finished university and started a job handling social media for a tour company. “I didn’t have a lot of money. I didn’t know how long I’d have to have off work, didn’t know if I’d get any sick pay.”

She had surgery on 4 December and went back to work in mid-January. Her grandfather had to drive her to and from the office. She watched Step By Step, the 2023 documentary following Mead and Miedema’s recoveries from their ACL injuries. “I related to everything they were saying, except that I don’t have a full-time physiotherapist to watch me in the gym. I’ve still got to go to work, sit behind a desk every day, getting stiff.”

Laverick worries about the influx of grassroots players. “Yes, let’s grow the women’s game, let’s watch it on TV, but it’s killing our bodies and it’s going to keep filtering down until we can work out what’s happening.” She has just signed with Chatham Town Women and hopes to play her first game in January. Millwall Lionesses is “one of the oldest and most recognisable names in women’s football”, according to its website. But Laverick is not going back. “You’d think that with the name there would be some kind of support, and there wasn’t.”

* * *

“The perceived epidemic of high-profile ACL injury rates is a manifestation of sex discrimination,” says Andy Williams, a knee and sports surgeon who specialises in ligament injuries and has treated Premier League footballers. “For years boys have been invested in, because there’s money at the end of it. They’ll be picked up aged six or seven and, from that moment on, they get better training, better equipment, better pitches.”

For example, a lot of thought has gone into codifying the warm-up and training regime for men, building core and leg strength, balance and agility. Fifa’s injury prevention programme takes about 20 minutes to complete, a few times a week. Several studies, particularly of adolescent females, found that adhering to this kind of plan significantly reduced non-contact ACL injuries. But not all players get access to one.

“Not long ago at Arsenal, we had to wait until early evening to use the swimming pool because the men were on site, regardless of whether they needed to go in the water,” writes Mead in her autobiography, Lioness.

“We’d try to find a square of grass where you could do your training sessions. There were no floodlights, so my brother-in-law put his car lights on. We had the cones out and you couldn’t even see where your feet were going,” recalls Fern Whelan, 35, a former defender for Everton and member of England’s youth squad, now an executive for equality, diversity and inclusion at the Professional Footballers’ Association, the trade union for England and Wales. Quite often, she would be at Everton’s training ground at 11pm, “because girls were not allowed to use the facilities until the boys had left”.

Hincks, now 35, used to feel lucky. She played elite football and even got paid – £450 a month at Chelsea; a fraction of the men’s salary and certainly not enough to live on. But, still, “I was getting access to the best that was available in women’s football at that time”. Now, she says she’s “infuriated”. Not only by memories of late-night training but by the constant sense that she was being deprived of the professional support enjoyed by the male players: nutritionists, psychologists, fitness coaches, medical staff, kit managers, technical staff.

And what about support for grassroots players? Alessandra Barreca, a former member of the Italian national youth team, used to play full-time, aged 16, with the first team at ACF Firenze, a women’s club based in Florence, Tuscany. “We never went to the gym. There were stairs to the stadium where people watched the game and I remember just jumping up them one by one, two, three steps, sprinting – that was part of the training.”

Now 35, Barreca lives in London where she works in IT in the city and is a striker for Actonians AFC in the Women’s National League Division One (tier 4). She ruptured her ACL and meniscus, a pad of cartilage in the knee, in December 2021, both menisci in the same knee in January 2023, and her meniscus again this February. “I’m lucky, I have private insurance,” she says.

She points to the lack of investment in the women’s game. “At one point I had 15 pairs of boots for different surfaces – all designed for men.” When she joined the Actonians, seven years ago, “we had to take it in turns to make sandwiches to bring to the pitch for the home game. Now, at least, we have more funding and we order pizzas.” She had played football “all my life” but first trained in a gym three years ago. “I didn’t know how to use weights because I’d never done it before. You’d be surprised. I didn’t know how to squat properly.” She is still in rehab and is undecided if she’ll play again. “Doctors say I shouldn’t, it’s too risky. But I’d like to try.”

Fourteen months after blowing her ACL playing for Ashmount Leigh (tier 7), Emily Robinson, 26, finally had surgery on the NHS this July. “If the hospital hadn’t called with a cancellation, I’d still be waiting now,” she says. “My life was on hold.” She’d had to cancel holidays and her knee felt wobbly – “so unstable” – every time she went down the stairs. She is grateful that, as a buyer for a construction company, she only has to visit construction sites once or twice a month.

She misses playing football and the camaraderie of her team. “I’m so unfit, and that makes you feel rubbish. My team and friends want me back and I want to go back – I love football. But it’s taken me 14 months to get here. It will be another nine months to be fully rehabbed and able to play again. So we’re talking two years. And what happens if I go back and it happens again?”

* * *

Things are changing. In 2018, the WSL, England’s highest domestic league, became professional. The result is that 12 teams are now full-time, players are given a minimum of 16 contact hours a week and each club has an academy. Eleven out of the 12 teams are affiliated with Premier League clubs. But, even now, “if you compare what the boys get with what the girls get in the academy, it’s shocking”, says Angus (not his real name), a physiotherapist at a Premier League club. “I work with the boys in a lovely air-conditioned room with all the equipment I want, with multiple physios, and the boys can come in for treatment most days. With the girls, I’m on the same site, but in a makeshift building often treating four players on my own.”

From age 14 or 15, most boys in the academy are schooled on site; many live with host families or are put up in hotels nearby. Strength and conditioning sessions are embedded in their daily routine. Girls are not educated on site or put up by host families. Girls’ training is scheduled after the boys’, at 7.30pm, twice a week. Then, at 8.30pm, they might have a strength and conditioning session with the coach in the gym. “Some of these girls live an hour’s drive away because they’ve been scouted from other academies,” Angus says. “So they finish at 9.30pm, get home at 10.30pm or 11pm, then they have to get up for school next day. ”

“In men’s football, an ACL rupture in a first-team player is a rare occurrence, because the weaker players have been weeded out as boys, plus they are better conditioned,” Williams says. “But women are now expected to play like men, twice a week in different time zones, and most haven’t had the conditioning the boys have had. It is changing. If you look at the women who won the Euros, they were ripped, proper athletes. In 10 to 15 years, if girls get the same opportunities as boys, you may find women’s rupture rate falls.”

* * *

When Hincks finally had surgery on the NHS, six months after she fell to the ground, she arrived with her knee looking like an explosion site. Crystal Palace had discouraged her from fundraising for private surgery, because “it would make the club look bad”. (The club say the people responsible for the women’s team at the time no longer work there.) She returned to fitness in December, nine months after the surgery. She played a few matches for Crystal Palace, but the club didn’t renew her contract. “I was top goal scorer, player of the year, and to be easily forgotten just by doing your ACL was really frustrating. I still had a lot to give,” she says. Her new team, AFC Wimbledon Women, finished last season as champions of Division One South East and were promoted to the Premier Division South.

The procedure to harvest a tendon has left its mark. “My calf is tight, my hamstring tight. I tore my achilles last year. Nothing is working quite right in that left leg,” Hincks says. “I can’t describe how difficult an injury it is to come back from. But this just seems to be what being a female footballer entails now.”

• This article was amended on 16 September 2024. Vivianne Miedema has been nominated for the Ballon d’Or previously, but has not won the award as a previous version said.