Why ACL Injuries Are More Common in Female Athletes: What the Research Really Says

ACL injuries are one of the most talked-about injuries in sports medicine—and for good reason. They affect hundreds of thousands of athletes every year, and female athletes experience ACL tears at 2–8 times the rate of their male counterparts in comparable sports. 

But why does this happen? 

It’s a question many parents, coaches, and athletes ask, and the answer is more nuanced than you might think. It’s not one factor—it’s a combination of anatomy, biomechanics, and hormones. The good news: once we understand these factors, we can better prevent the injuries from happening in the first place. 

Let’s break it down. 

1. Anatomy: The Structure of the Knee Matters 

While anatomy alone doesn’t “cause” ACL injuries, certain structural differences can contribute to increased risk: 

• Wider Pelvis & Knee Alignment 

Female athletes typically have a wider pelvis, often leading to a greater Q-angle (the angle at which the femur meets the tibia). 

This can predispose the knee to collapse inward (valgus), especially during cutting or landing movements—one of the main mechanisms of ACL injury. 

• Smaller ACL Size 

Studies show that on average, women tend to have smaller ACLs and narrower femoral notches (the space the ACL passes through). 

Smaller ligaments = less room for stress tolerance, especially under high-speed or high-load movements.

2. Biomechanics: How the Body Moves Under Stress 

Movement patterns are one of the most significant contributors to ACL risk—and they are trainable. 

Female athle

tes, especially during adolescence, are more likely to demonstrate:

• Knee Valgus Collapse 

The knee driving inward during landings, decelerations, or cutting maneuvers dramatically increases strain on the ACL. 

• Quad-Dominant Landing Patterns 

Using mostly the quadriceps instead of sharing the load with the hamstrings and glutes can increase anterior tibial shear forces—the exact force that stresses the ACL. 

• Less Hip and Trunk Control 

Deficits in hip strength or neuromuscular control can lead to less stable landings and slower corrections when the body is off balance. 

The key takeaway: biomechanics are modifiable, especially through strength, plyometrics, and neuromuscular training. 

3. Hormonal Influences: A Complex and Emerging Research Area 

Hormones—particularly estrogen and relaxin—may affect ligament laxity and neuromuscular control. 

What we know: 

● Estrogen receptors exist on the ACL. 

● Certain phases of the menstrual cycle may correlate with slightly increased injury risk, possibly due to changes in ligament elasticity or coordination.

What we don’t know: 

● Whether these hormonal shifts are strong enough on their own to cause injury. ● How significant the effect truly is compared to biomechanics or strength deficits. 

Bottom line: hormones may contribute, but they are not destiny. 

So… What Can We Do About It? 

While some factors (like anatomy) can’t be changed, the most influential risk factors can absolutely be improved through targeted training. 

Effective ACL prevention programs include: 

● lower-body strength (glutes, hamstrings, quads) 

● plyometrics with proper landing mechanics 

● neuromuscular and balance training 

● deceleration and cutting practice 

● core and trunk control 

● fatigue-resistant conditioning 

Programs like FIFA 11+, PEP, and customized PT-led approaches have shown reductions in ACL injury rates by up to 50% or more. 

Final Thoughts

ACL injuries are not inevitable—especially for female athletes. Understanding the “why” behind the higher injury rates empowers athletes, parents, and coaches to take proactive steps to reduce risk. 

With smart training, strong biomechanics, and good coaching, female athletes can compete with confidence and build resilient, powerful knees that support their performance for years to come.