Cleo Pallister-Turley, a forward for Cardiff university’s women’s rugby team, winces as she recalls two major concussions from playing rugby. “Girls ask me, ‘aren’t you worried about getting injured?’,” the biomedical sciences student said. “I enjoy the physicality and the intensity. For me, no other sports compare.”

Women’s rugby has enjoyed significant growth in recent years. Women now make up a quarter of players worldwide, according to World Rugby, and more than 400 clubs offer rugby to women and girls around the UK; in the 1990s, only a handful existed.

The increase in popularity, however, has not been matched by investment in research to help keep female rugby players safe, despite the now well-known long-term health risks of the game’s repetitive head impacts.

At the professional level, the current bar for taking a woman off the pitch for a head injury assessment is simply 12% less than the impact threshold that has been calculated for men – a potentially dangerous gender research gap that medical engineers at Cardiff University are attempting to remedy with a groundbreaking new study.

The researchers from the university’s school of engineering and world-leading brain research imaging centre aim to produce the first ever head impact assessment protocol in women’s rugby backed by scientific evidence. The team believe the work will also deliver the first ever academic insights into the relative long-term risks of female contact sport.

Medical engineers have followed the university’s female rugby team during training and matches throughout the academic year, drawing on impact data from the players’ instrumented mouth guards, cognitive tests, MRI scans and computer modelling – the first time, to the researchers’ knowledge, that all four different strands of research have been conducted on the same group of people.

The findings of the study, titled “Towards precise brain health guidelines for women’s rugby”, should be published by the end of 2026.

Dr Peter Theobald, the project’s lead researcher, said: “Women’s sports research is historically underrepresented, and with most research we can look 10, 15, 20 years into the past for data, but not with women’s rugby; it hardly existed.

“The female brain is softer and more vulnerable to concussion … what we don’t know yet is whether that translates to a greater risk of the effects of subconcussive brain injury.”

The goal of the study is not to dissuade women and girls from taking up rugby, Theobald added, but to “shed light on the risks so people can make an informed decision”.

Taking part in hours-long MRI and other imaging scans at Cardiff’s brain research imaging centre last week, Pallister-Turley and teammate Ffion James said they were thrilled to participate in the study, despite the demands on their time just before the summer exam period and the annual varsity match against Swansea.

The players changed into magenta hospital gowns before technologists helped them clamber up to the machines, legs and bare feet sticking out while the Disney film The Incredibles played on a monitor inside the chamber to keep them entertained.

The state-of-the-art machines – one of Cardiff’s facility systems is one of only four in the world – hummed and whirred as the rugby players were ferried from one scan to the next.

“I do feel safer knowing there’s going to be more research,” law student James said, perched on a chair in an examination room in a break between tests. “Before I step on the pitch, I never think I’m going to get injured, it’s only when you see someone down you think about it.”

“I feel like I can be part of the change. Even if it’s a small part, it’s exciting, and hopefully in years to come it will make a change for women in sport and women in rugby.”

Pallister-Turley said: “Any injury would be worth the game for me. The reason I play is for my teammates; all my best friends have come through rugby. The group environment is so accepting and so much fun … it’s love of the game.”

The findings might not make for comforting reading. Studies to date show male rugby players have a 14% higher risk of chronic traumatic encephalopathy (CTE), a progressive degenerative disease, for every additional year played. Male players with long careers are also at increased risk of dementia and neurodegenerative diseases.

In 2023, more than 300 former football, rugby league and rugby union players in the UK announced a lawsuit against the Welsh Rugby Union, England’s Rugby Football Union and World Rugby over brain damage they claim they suffered playing the game. The case is ongoing.

Freya Butcher, a medical engineering PhD student working on the study, said: “It’s not as simple as introducing helmets, or changing the rules of the sport, because then other issues would crop up as players compensated for that.

“Women’s and men’s rugby are played quite differently, and their brains are different anyway, so looking at what happens in the men’s game doesn’t mean we understand the impact on women’s brains and bodies.”

The gender gap in sports and exercise research remains vast. In 2020, an audit found that just 6% of sport science research is specifically about female athletes; another, in 2023, found more than nine in 10 first (or lead) authors were men, and women made up just 13% of authors.

The work with the rugby team undertaken by Theobald and Butcher will also evaluate how musculoskeletal health, strength and fatigue are influenced by menstruation, and breast health – another area of sports science that Butcher said is critically understudied.

“It’s still a taboo topic. Sometimes the girls have huge bruises on their breasts and sides after games, and they agree that if it was elsewhere, they wouldn’t hesitate to get it looked at,” she said.

“Compression and impact on the breast may be linked to problems lactating and breastfeeding. But right now, female players don’t have adequate protective wear or strategies for dealing with that.”

On the side of the pitch at Cardiff Arms Park before the annual varsity match against Swansea, each player on the Cardiff women’s rugby team grabbed their personally moulded, Bluetooth-enabled mouthguard, recognisable by the initials on the case.

As the whistle blew and the game got under way, Theobald and Butcher studied a tablet screen that tracked impact on the players’ teeth, used to determine impact on the head and brain.

Cardiff thumped their visitors 81-0, in a match that saw two Swansea players retire with injuries. Before the celebrations began, though, the study participants’ balance and short-term memory were tested so the researchers could figure out later whether the results correlated with the head impact measured by the mouth guards, and MRI scans in the days before and after the match.

“[The study] helps me be less worried,” James said. “I always think, if I have daughters, I know that with this research and hopefully more in years to come, they are going to feel safer stepping on to a rugby pitch … my parents were terrified, but hopefully, I won’t have to experience that.

“I want my daughters to be able to run on to that pitch and think: ‘I’m going to be OK.’”