Women athletes are significantly more likely than men to suffer tears of the anterior cruciate ligament (ACL), a small but crucial structure in the knee whose failure can derail months of a person’s life.
The ACL is one of four major ligaments that stabilize the knee, running diagonally through the center of the joint to connect the femur (thighbone) to the tibia (shinbone). It prevents the tibia from sliding too far forward, guards against hyperextension, and resists rotational forces during cutting and pivoting. These functions make the ACL especially important in sports that demand rapid deceleration, sudden changes of direction, and explosive jumps, such as soccer, basketball, skiing, and gymnastics. When the ACL ruptures, athletes often describe a popping sound, immediate swelling, and a sense that the knee is “giving way,” signs of a complete tear that typically leaves the joint mechanically unstable.
Epidemiologic studies show that women sustain ACL tears at much higher rates than men playing the same sports, with female‑to‑male incidence ratios reported at roughly 3.5 in basketball and 2.8 in soccer, and overall risk estimates ranging from two to eight times higher for women. Researchers now point to a convergence of anatomical, hormonal, and neuromuscular factors that, together, place the female ACL at greater peril.
Anatomically, women tend to have a “knock-kneed” alignment, which means that the way loads pass through the knee is altered when landing or cutting. Imaging and cadaver data show that, even after adjusting for body size, women often have smaller ACLs and narrower intercondylar notches (the bony groove that houses the ligament), so the tissue is thinner and resides in a tighter space. Vehniah Tjong, MD, noted that thinner ligament tissue requires less force to fail, potentially raising the risk of rupture during high‑stress maneuvers.
Hormones add another layer of complexity. The ACL contains receptors for estrogen and progesterone, and several studies report clustering of ACL injuries during particular phases of the menstrual cycle, such as mid‑cycle or around menses. Estrogen‑related shifts in collagen properties may influence ligament stiffness and laxity, changing how the ACL responds to sudden loads. Although no consensus supports modifying hormones purely for injury prevention, menstrual biology is increasingly recognized as a relevant contributor to risk.
Neuromuscular patterns may be where differences become most visible on the field. Female athletes more often land from jumps with a more upright trunk, straighter knees, and less hip and core engagement than men. The “female ACL” has slower hamstring activation, greater reliance on the quadriceps, and difficulty rapidly “stiffening” the knee when the tibia shifts forward; all patterns that increase strain on the ACL. Dynamic knee valgus, where the knees cave inward during cutting or landing, and inefficient core stability further amplify these harmful forces. In combination, these features make the female knee more vulnerable in the very movements that define modern sport.
A torn ACL is rarely a one‑season problem. Because the ligament sits in synovial fluid and has a limited blood supply, complete tears do not reliably heal on their own. Surgical reconstruction is often required to restore stability, and meniscal or cartilage damage is frequently repaired at the same time. Rehabilitation commonly spans nine to twelve months before full‑speed competition is considered, and a history of one ACL tear increases the risk of a future injury by about sixfold.
Data from large clinical cohorts show that while graft failure rates may not be higher in women, female athletes are less likely than men to return to their prior level of competition in the years after reconstruction. Quadriceps strength deficits often last longer in women, and altered neuromuscular patterns remain, both of which are linked to reinjury risk. Psychologically, fear of reinjury and reduced confidence can further delay return to sport, and these factors appear particularly prominent among female athletes.
These disparities take on global visibility at the Olympics, where millimeters of ligament and fractions of a second can define a career. Many Olympic sports with high female participation—soccer, basketball, handball, gymnastics, and alpine skiing among them—feature exactly the high‑velocity pivots, cuts, and landings most associated with noncontact ACL tears. As worldwide participation in girls’ and women’s sports has expanded, the absolute number of ACL injuries has climbed, and the higher female injury rate has become impossible to ignore on the world stage.
