When Texas Tech soccer player Sam Courtwright tore her ACL, she was completing a move she had practiced countless times before.

With only minutes remaining in a training drill, Courtwright passed the ball, stepped backward to regain her balance and heard a pop. The injury cost her a place in the U-20 Women’s World Cup and forced her to confront the physical and emotional demands of another yearlong recovery. It was also her second ACL tear.

Her experience is familiar well beyond soccer. Across women’s college basketball, volleyball, lacrosse and other sports built around jumping, landing and quick changes of direction, ACL injuries remain a persistent problem.

An ACL tear can happen when an athlete plants her foot, lands from a jump or suddenly changes direction. Sometimes another player makes contact with the knee, but many tears happen without any collision at all.

Female athletes are estimated to face between two and six times the ACL injury risk of male athletes in comparable sports. The disparity has been documented across several sports, though soccer and basketball have received much of the research attention because both require frequent cutting, jumping and rapid deceleration.

For decades, attempts to explain that gap have focused heavily on women’s bodies. Researchers have studied pelvis width, knee alignment, knee joint size, hormonal fluctuations and differences in muscle activation.

But researchers increasingly argue that biology alone cannot explain why so many female athletes are getting hurt, or why proven prevention programs still are not used consistently.

The biological explanation

Dr. Elizabeth Gardner, an orthopedic sports medicine surgeon and the head team physician for Yale Athletics, divides the commonly discussed risk factors into three broad groups: anatomical differences, biomechanical and muscular patterns, and hormonal influences.

Female athletes may rely more heavily on their quadriceps than their hamstrings during certain movements, Gardner explained. The hamstrings help control forward movement of the knee, acting, in her words, like “the brakes on the ACL.”

Dr. Gardner poses with the Yale Bulldog

Landing mechanics can also contribute. Some athletes land in a more upright position, with less bending through the hips and knees to absorb force. The knees may move inward as an athlete lands or changes direction, placing additional stress on the joint.

Those mechanics matter in far more situations than a soccer player planting to change direction. A basketball player coming down from a rebound, a volleyball player landing after a block or a lacrosse player cutting around a defender can encounter similar forces.

The good news, Gardner said, is that these movement patterns are not fixed. They can be coached and strengthened.

“This needs to be thought of not as a knee injury, but as a whole lower-body, how-you-move injury,” Gardner said. “It’s not knee rehab. It’s whole lower-body rehab.”

Dr. Jackie Whittaker, an associate professor of physical therapy at the University of British Columbia and a senior research scientist at Arthritis Research Canada, believes the field has spent too much time measuring biological characteristics because they are easier to isolate than the environments in which athletes develop.

Researchers can measure the width of an athlete’s hips, the angle of her knees or a change in hormone levels. It is considerably harder to quantify when she first received quality strength training, whether her youth team had medical support or whether her facilities and coaching matched what boys received at the same age.

“The idea of there being a singular risk factor doesn’t make any sense,” Whittaker said. “There’s multiple factors at play.”

Girls also tend to mature physically earlier than boys, meaning that even athletes who enter organized development programs at the same age may not arrive with the same opportunities for strength and movement training at the developmental stages when it can be most useful.

That becomes more important as college sports grow faster and more physically demanding. Women’s basketball players are bigger and quicker, volleyball players are jumping repeatedly at high intensity and soccer and lacrosse players cover large amounts of ground while accelerating and changing direction. Athletes may enter those environments without enough years of strength and movement training to match what their sports require.

Whittaker described it as a mismatch between what athletes have been prepared to handle and what their sports now demand from them.

How much do hormones matter?

Few explanations have received as much attention as the menstrual cycle.

Gardner said some studies and meta-analyses have reported a higher incidence of ACL tears around the late follicular and ovulatory phases, when certain hormone levels change.

However, she stressed that women tear their ACLs throughout the menstrual cycle and called the attention placed on hormones “a little overblown.”

Whittaker was more categorical.

“Women and girls tear their ACLs at any time of the menstrual cycle,” she said. “There is no one period in the menstrual cycle that leads to more tears or worse tears.”

The evidence remains mixed. Earlier research has suggested possible associations between cycle phase and injury, but reviews have also pointed to small samples, unreliable estimates of cycle timing and inconsistent methods. A 2025 review of sex hormones and ligament properties concluded that menstrual-cycle changes were unlikely to affect ligament looseness in a clinically meaningful way.

Menstrual health still matters. Pain, fatigue, heavy bleeding, anxiety or brain fog can affect how prepared an athlete feels to train or compete.

What it cannot do is replace the basics of injury prevention. Tracking a cycle is not a substitute for strength training, recovery, medical support or regular neuromuscular work.

“When there’s no evidence, we come up with myths to fill the gaps,” Whittaker said.

Prevention programs already work

The clearest evidence in the ACL debate may not be about why women get injured, but what teams can already do to reduce the risk.

Exercise-based neuromuscular programs can reduce ACL tears in female athletes by as much as 61 percent. A major 2025 evidence review developed for the International Olympic Committee’s Female, Woman and Girl Athlete Injury Prevention consensus reached that estimate after evaluating lower-extremity injury-prevention research.

The routines combine strength, balance, jumping, landing and change-of-direction work. They can be built into a team warm-up rather than treated as a separate medical intervention.

Programs such as FIFA 11+ and Knee Control have been studied extensively, but the underlying approach is not limited to soccer. Similar neuromuscular training has been used in basketball, volleyball, lacrosse and other sports where athletes repeatedly jump, land and change direction.

Whittaker recommends that athletes perform a prevention routine for at least 15 minutes, three times each week. Ideally, she said, it should become part of the warm-up every time a team practices or competes.

Gardner said repetition matters because an athlete cannot consciously analyze her mechanics in the middle of competition.

A guard driving toward the basket cannot stop before landing to remind herself to bend her knees. A volleyball player does not have time to review her mechanics after jumping at the net. A midfielder cutting away from a defender cannot work through a checklist before planting her foot. The movements have to become automatic.

“You have to do this in a controlled, conscious setting over and over and over again,” Gardner said, so that correct movement becomes “second nature.”

The problem, then, is less about whether prevention tools exist than whether teams use them often enough. Research on neuromuscular training has repeatedly found that adherence matters.

Responsibility cannot fall only on athletes

It is easy to tell women athletes to become stronger or learn how to land. It is harder to ask whether their institutions have provided the time, staff and facilities required to do so.

A well-funded Division I program may employ athletic trainers, strength coaches, physical therapists, nutrition specialists and team physicians. Athletes at smaller schools may have far less individual support, even while competing under similar physical demands.

And the gap often starts before an athlete reaches campus. Someone who spent her teenage years without consistent strength training or high-quality movement coaching has to build that foundation while simultaneously handling college practices, travel, games and academics.

Gardner said coaches do not need advanced medical qualifications to lead established warm-up programs. Schools and clubs can train coaches to supervise the exercises and make prevention a standard part of practice.

“We’ve got to teach young girls how to move,” Gardner said. “Somebody’s got to take responsibility for this, and it can’t just be the medical staff.”

For Whittaker, the immediate solution is to mandate an evidence-based prevention program across women’s teams. The broader solution requires equal investment.

“Invest as much into your female, women and girl athletes as you do into your male, men and boy athletes,” she said.

That means looking beyond any single sport or any single explanation. It means strength development, knowledgeable coaching, medical support, adequate recovery and facilities that prepare athletes for the demands of college competition.

Not every ACL tear can be prevented. Biological differences may continue to contribute to the injury gap, and athletic competition will always involve risk.

But prevention programs already exist, they can be incorporated into ordinary practices and the potential reduction in injuries is substantial. The question for college programs is increasingly not whether ACL tears can be reduced, but whether schools will consistently use what researchers already know works.