Why female athletes tear their ACLs more: The science, bias, and human cost

In elite sport, careers often change in the span of a single misstep, a twist, a pivot, a landing that goes wrong by a fraction.

For female athletes, that moment comes more frequently and more devastatingly than it does for men. Across football, athletics, and basketball, women are consistently more vulnerable to anterior cruciate ligament (ACL) injuries, suffering tears anywhere from two to eight times more often than their male counterparts.

It is one of the starkest and most persistent inequalities in sport.

The numbers tell one story, but the athletes’ experiences tell another, more humane one.

In June 2025, India’s 100m hurdles star and Asian silver medallist Jyothi Yarraji tore her ACL during a routine training session, an abrupt end to one of the most promising seasons of her career.

Footballers Bala Devi and Aditi Chauhan have both endured long periods on the sidelines after serious knee injuries. Their recoveries stretched across months, and their return-to-play timelines constantly shifted with each setback.

Chauhan, one of India’s most decorated goalkeepers, experienced two ACL injuries during her career. Her reflection on those periods cuts sharply through the scientific jargon.

"It is for sure one of the toughest things that I’ve been able to overcome," she told The Bridge in a previous interaction. "It’s a very tough injury, and it’s a very tough process of recovery."

Globally, this trend has become almost an epidemic, with more female footballers, sprinters, basketball players and skiers undergoing ACL reconstruction in the past few years than any other comparable period.

It’s tempting to blame bad luck, overuse, or poor pitches.

But the truth is layered, scientific, and uncomfortable: women face a higher risk of ACL injuries because their bodies move, function, and respond to stress differently from men’s, and because for decades, the sports science that should have protected them was never built with them in mind.

On the left - a normal ACL. On the right, the ACL is torn- photo credit: Atlantaboneandjoint.com

The anatomy problem

The first layer lies in the structural differences of the female body. In many women, the intercondylar notch, the groove at the end of the femur where the ACL sits, is naturally narrower than in men.

The ligament itself is often smaller, giving it slightly less structural tolerance when subjected to high torsional forces.

Pelvic anatomy adds another dimension. A wider pelvis changes the alignment of the knee joint, increasing what is known as the Q-angle. When force travels down the leg, this angle can encourage the knee to collapse slightly inward, a movement called valgus.

Difference of Q-angle in men and women- photo credit: Relentless Athletics

Valgus collapse is one of the most common mechanisms of ACL rupture, especially when paired with quick deceleration or landing from a jump.

Decades of biomechanical studies have consistently found that female athletes, even at elite levels, display more valgus positioning during dynamic movements than male athletes performing the same actions.

These differences are not flaws or weaknesses; they are simply variations of biology. But when training programs, strength frameworks, screening protocols and injury-prevention strategies are modelled on male anatomy, those variations become vulnerabilities.

The difference in the intercondylar notch- photo credit: semanticscholar.org

Neuromuscular patterns that emerge early

Movement patterns form long before athletes reach elite stages. Researchers examining adolescent sport found that girls, on average, tend to rely more on their quadriceps to stabilize movement, whereas boys develop stronger hamstring activation.

Because the hamstrings help prevent the tibia from translating forward, one of the primary motions involved in ACL rupture, underdeveloped hamstring recruitment in girls can gradually set the stage for greater ligament stress.

Differences also appear in trunk control, hip strength, and landing mechanics. Female athletes often land from jumps with a more upright torso and straighter knees, both of which increase ACL loading.

These are modifiable patterns, but only if they are identified early, and only if coaches, trainers, and physiotherapists are trained to spot them.

Where hormones enter the equation

The role of hormones remains one of the most nuanced and contested aspects of ACL science.

What is known, however, is that the ACL contains receptors for estrogen and progesterone. Estrogen, in particular, can influence collagen properties and ligament laxity.

During phases of the menstrual cycle when estrogen peaks, some women experience looser ligaments, reducing the ACL’s stiffness and potentially its ability to withstand sudden forces.

Not all researchers agree on the magnitude of hormonal impact, and not all female athletes experience meaningful changes. But the possibility of fluctuating ligament stability adds another dimension to risk, one that almost no training program has historically accounted for.

The real culprit: A century of male-biased research 

For decades, the most influential studies in sports science used male subjects almost exclusively.

Reviews of leading sports journals have shown that roughly 70% of studies focus solely on men. Only about 9% examine only women. Even mixed-sex studies often have overwhelmingly male participant pools.

Researchers once justified this by claiming women’s hormonal cycles introduced “unpredictable variables,” making studies harder to control. The solution was simply to leave women out.

What this meant, unintentionally but undeniably, is that almost every major training philosophy, rehab protocol, exercise progression, and injury-prevention program was designed based on how men move, how men land, how men rotate, and how men fatigue.

Coaches were taught to look for male injury mechanisms. Physiotherapists built their practices on male data. Athletics programs were designed around male biomechanics.

Female athletes, in turn, were screened, trained, and rehabilitated against standards that did not fit the realities of their bodies.

Aditi Chauhan’s experience mirrors this reality. She didn’t just face the physical trauma of injury; she faced a system unprepared to support women fully.

"You have to be really strong mentally to overcome all those things," she says. "There were times when I was really down and didn’t feel like playing again. There are a lot of doubts; you go through lots of emotions in that period."

Sports scientists in recent years have openly acknowledged this gap. Many have called it one of the most glaring blind spots in modern sport, an omission that has allowed an injury disparity to persist for generations.

The mental rupture

The ripple effect goes far beyond time lost on the field or track. An ACL tear is not merely a physical injury; it is often a psychological rupture as well. Athletes face months of isolation, self-doubt, and physical rebuilding.

Strength and conditioning coach Krishna Chimminiyan explains it:

“Physically, the rehab process is measurable: tissue healing, strength progression, functional milestones. But mentally, it’s a much messier journey. After an ACL injury, the athlete doesn’t just lose function; they lose trust in their own body. The major criterion to return to competition after ACL surgery is mental readiness.”

That psychological readiness is often where female athletes face an additional, invisible burden, she adds.

“There’s fear of re-injury, loss of identity, anxiety about being behind teammates, and this constant internal negotiation between courage and caution,” Krishna says. “And women often carry an additional emotional load, expectations, representation, limited career windows, and sometimes an unconscious cultural pressure to be ‘tough enough’ to not complain too loudly.”

She adds that psychological support is not optional; it’s essential.

“Recovery absolutely requires psychological support. Whether it’s a counsellor, a sports psychologist, or simply a support system that reassures them that their worth isn’t tied to performance. They need people around them who check in not just with: ‘How’s the knee feeling?’ but also: ‘How are you feeling in all this?', she adds.

This emotional landscape explains why athletes like Aditi Chauhan say, “It takes a lot out of you,” and why returning after two ACL tears felt to her like a reclamation of identity: “If I could overcome this, then I can overcome anything in life.”

These aren’t isolated stories. They represent a systemic burden placed on women by a sporting ecosystem that has never fully studied how to protect them.

Shift in momentum

The good news is that the tide is turning. As women’s sport gains global visibility and commercial investment, research priorities are changing. Universities and high-performance centres in Europe, the US, Norway and Australia have launched specialized labs focused on female biomechanics.

Some football federations have introduced menstrual-cycle-informed training calendars. Neuromuscular injury-prevention programs designed specifically for women have shown reductions of 40 to 60 per cent in ACL injuries when implemented consistently.

Footwear and equipment manufacturers are beginning to design products around the female foot and joint structure, instead of assuming that “shrink it and pink it” is enough. Rehabilitation specialists are re-evaluating return-to-play criteria through a sex-specific lens rather than relying on decades-old benchmarks.

And maybe most importantly, female athletes themselves have become vocal. In global football, star players have demanded better surfaces, more research, and a serious commitment to solving the ACL epidemic. Their advocacy has pushed federations and leagues into action.

In India, where women’s sport is rapidly expanding, this issue is even more urgent. As more athletes enter professional pathways in football, athletics, kabaddi, hockey, and badminton, the training environment must evolve with them.

That means investing in female-specific injury surveillance, strengthening youth-level neuromuscular training, educating coaches, building rehab structures that reflect global standards, and encouraging Indian medical institutions to lead research instead of relying solely on international data.

The athletes deserve nothing less. 

ACL injuries will never disappear completely, not in a world where athletes push their bodies to the very limits of human performance. But the gulf between men and women does not have to be as wide as it is today.