Women’s elite sport has been modelled after (and largely still is) the corresponding male discipline without any meaningful adaptation to female anatomy or physiology. In an article for CO24, Daniel Moreau explained that the “female athletic body has been treated as a smaller version of the male form rather than a physiologically distinct entity with unique health considerations.”[1]
Menstrual Cycles, Performance and Injury Risks
Addressing these physiological differences has long been a taboo. After her first-round defeat at the Australian Open in 2015, Heather Watson, at the time the number one British female tennis player, attributed the loss to her menstrual cycle. While celebrated as a defining moment by some[2], her reference to her menstrual cycle has been left out in some mainstream media coverage, which only reported on Watson’s symptoms of “nausea”, “blurred vision” and “light-headedness”[3]. This is in stark contrast with Watson’s Australian Open defeat in 2013 due to glandular fever which was widely cited[4]. The difference in reporting highlights that the stigma has never been about athletes talking about injuries or health issues affecting their performance, but physiological symptoms which primarily or exclusively affect women.
This stigma has not been limited to elite sports. Karen Houppert, author of “The Curse: Confronting the Last Unmentionable Taboo, Menstruation,” argues that this taboo is prevalent for women in the workplace. In a CNN interview, she postulates that the secrecy of not talking about menstrual cycles at work was partly to do with workplaces historically being “men’s spaces,” which women have adapted to. The same is true for elite sports. They were designed as men’s spaces to which female athletes had to and still have to adapt to regardless of physiological or anatomical differences. Research from the University of Bath, University College London and St Mary’s University found that football players in the English Women’s Super League were six times more likely to experience a muscle injury in the days leading up to their period compared to when they were on their period.[5]
Women’s physiological differences and their impact on female athletes are by no means limited to menstrual cycles.
The Prevalence of ACL Injuries
ACL injuries, short for anterior cruciate ligament, are knee injuries caused by sudden stops, changes of direction or jumps and are among the sporting injuries with the longest recovery time. While both male and female athletes can and do sustain ACL injuries, they appear significantly more prevalent in women, resulting in devastating impacts on women’s career development.
During the 2026 Winter Olympics, American alpine ski racer and Olympic gold medallist Lindsey Vonn made headlines when announcing her intention to ski with a torn ACL[6] and subsequently crashing in the downhill race. This has not been Vonn’s first ACL injury; she has suffered several serious leg injuries over the years, even forcing her to retire in 2019 before making a comeback in 2024.[7] Vonn’s story is far from unique in elite female ski racing. Croatia’s Janica Kostelić, one of the most decorated female skiers and the first women to win four Olympic gold medals in alpine skiing, three of them in a single Olympics, was plagued by constant ACL injuries requiring multiple knee surgeries and leading her to miss several competitive seasons throughout her career.[8]
A similar picture has emerged in women’s football. In the 18 months leading up to 2024, an estimated 195 elite players in English women’s football suffered ACL injuries.[9] Between 25 and 30 players, enough for an entire squad, missed the 2023 Women’s World Cup because of ACL tears.
Various sources allege that ACL injuries are between two to ten times more prevalent in women compared to men. A 2024/2025 study published in the British Journal of Sports Medicine (“the Study”) questioned this allegation, arguing that the methods for calculating ACL injury rates are biased as they fail to consider gendered inequalities women face in sports, such as fewer training opportunities, smaller team sizes and limited access to resources.[10]
The question that needs to be addressed is whether women really are physiologically more prone to sustain ACL injuries or whether the current backdrop of elite women’s sports puts female athletes at an increased risk of those injuries.
Injury risk in training vs competition The 2025 FA Injury and Illness Surveillance Study (“the FA Study”) showed that injury incidence for ACL and other types of injuries was greater in matches than training.[11] The Study found that female athletes often spend more time competing in matches, where the injury risk is high, than in training compared to their male counterparts.[12]
Physiological inevitability or broader gender bias? The Study also considered how gendered factors like unequal compensation, substandard equipment, and external responsibilities (e.g., caregiving) can impact women’s ACL injury risk.
Insufficient data There is an urgent need for more research into ACL injuries and their effect on women and female athletes. In December 2023, UEFA announced the introduction of an expert panel on women’s health to seek a deeper understanding of ACL injuries and their frequency among female players. Without additional data, it is hard to quantify whether and why women are more likely to sustain ACL injuries and how this risk can be mitigated in adapting training and competition schedules, allocating resources and addressing underlying gender biases.
Legal implications
For sporting clubs employing female and male athletes in the United Kingdom, the outcomes of any scientific studies on the impact of menstrual cycles and ACL injuries on women’s performance and injury risk will be of great relevance. Employers may be found liable for direct and/or indirect discrimination on the grounds of sex if they fail to react to scientific data on women’s health.
Direct Discrimination on the grounds of sex contrary to s13 Equality Act 2010 The Study has highlighted that unequal training opportunities (i.e., lesser time spent in training) increases an athlete’s ACL injury risk and that women spend less time in training than they do in competitions where the risk is much higher. Failing to provide equal training opportunities to male and female athletes by their employer club might arguably form the basis of a direct discrimination claim albeit one that is largely fact specific when it comes to identifying any statutory or evidentiary comparators. Similar claims might be brought for the unequal provision of funding and equipment between male and female athletes if future research can establish a sufficient link between the unequal treatment and increase in ACL injury risk to argue that it constitutes less favourable treatment.
Indirect discrimination on the grounds of sex contrary to s19 Equality Act 2010 Even where employer clubs provide the same facilities, training opportunities and funding to male and female athletes, if future research finds that training schedules that do not adapt to female physiology can lead to greater injury risk or lower performance in female athletes, it can constitute a discriminatory provision, criterion or practice. More concrete research into the effect of menstrual cycles on elite sporting performance or data that women are in fact more prone to ACL injuries might require clubs to adapt their training to ensure women are not adversely affected by training schedules that were created for male performers. In 2020, Chelsea FC Women introduced a training programme around players’ menstrual cycles to enhance performance and limit injury risk[13] which can serve as an example to other clubs to finally take steps to adapt elite sport and training to women rather than the other way around.
Carla Fischer
[1] Women’s Health Issues in Elite Sports: Hidden Challenges – CO24
[2] Sport and menstruation: Periods stop play? | CNN
[3] Australian Open 2015: Heather Watson out in round one – BBC Sport
[4] Heather Watson diagnosed with glandular fever – BBC Sport
[5] Female athletes more likely to get injured at certain points in their menstrual cycle | UCL News – UCL – University College London
[6] Lindsey Vonn can still ski with a torn ACL, experts say | AP News
[7] Lindsey Vonn: American crashes out in women’s downhill at Winter Olympics as Breezy Johnson wins gold – BBC Sport
[8] Janica Kostelic | Biography, Medals, & Facts | Britannica
[9] Future of Football: Why ACL injuries have been on rise in women’s game – and the technology and solutions to fix it | Football News | Sky Sports
[10] Limitations of athlete-exposures as a construct for comparisons of injury rates by gender/sex: a narrative review | British Journal of Sports Medicine. Are women really more prone to ACL injuries? New study challenges common claims
[11] The Football Association Injury and Illness Surveillance Study: The Incidence, Burden, and Severity of Injuries in English Women’s Domestic Football—A 5‐Year Prospective Cohort Study – Sprouse – 2025 – Scandinavian Journal of Medicine & Science in Sports – Wiley Online Library
[12] Limitations of athlete-exposures as a construct for comparisons of injury rates by gender/sex: a narrative review | British Journal of Sports Medicine. Are women really more prone to ACL injuries? New study challenges common claims
[13] Chelsea Women tailor training to players’ menstrual cycles | News | Official Site | Chelsea Football Club
