The Female ACL: Why Women Are More Susceptible to ACL Tears

The anterior cruciate ligament (ACL) is a key ligament in the knee that stabilizes the joint by connecting the femur to the tibia. It helps prevent the anterior shift of the tibia and protects the knee during rotational movements. ACL injuries usually occur in sports involving valgus (inward) and rotational force at the knee. This could be due to sudden changes in direction, quick stops, or landing incorrectly.

There is an increase in the research being done on women and sports (finally!). Both these topics are a particular interest of mine and I have spent the past few years furthering my knowledge on the endocrine system and how that affects us as women, not only in sports, but on a day-to-day basis. But more on that later…

Unfortunately (and fortunately), I have experienced a non-contact ACL rupture (and MCL / meniscus injury… I know…!?) a few years ago I treated non-surgically and surgically. 

In the most recent research ”Why are women at greater risk of anterior cruciate ligament injury? A systematic review with meta-regression analysis” by Simon G. F. Abram, et al. (2021), their findings suggested that women are 3 to 6 times more likely than men to suffer non-contact ACL injuries due to neuromuscular imbalances, hormonal fluctuations, and anatomical differences.

But why?

There are several reasons why women are at greater risk of ACL injuries:

1. Anatomical Differences:

Women generally have a wider pelvis (because we were designed to fit a small human inside of us), which causes the angle between the femur and tibia, known as the Q-angle, to be larger. This increased Q-angle places more stress on the ACL, particularly during activities like jumping or pivoting.

Women’s ACLs are often smaller in size. 

Women generally have a narrower intercondylar notch. This can pinch the ACL ligament during knee movements, increasing the risk of tears. It also means the ligament has less space to move freely, which increases shear forces during twisting or pivoting.

2. Infradian Rhythm:

Have you heard of the infradian rhythm? If not, it’s time to dive into the conversation about how women’s hormones impact nearly every aspect of their lives—sports performance, nutrition, sex life, productivity, recovery, injury prevention, and so much more.

Experts like Alisa Vitti, Dr. Stacy Sims, and Dr. Sarah Hill have been leading the charge in educating women about their hormonal cycles. Listening to their work often creates a lightbulb moment for women who realize they’ve spent so much of their lives unaware of the daily and cyclical changes their hormones bring.

Many of my clients experience this same revelation. After reading a few books from my free women’s health library, they often come back to me saying:
“Why has no one ever told me about this? Why aren’t they teaching this to young women in schools? It makes so much sense! Where do I even begin?”

The answer is simple: cycle syncing. It’s a game-changer.

Crash Course in Cycle Syncing

(Note: This applies to women who are not on hormonal birth control.)

Cycle syncing is a method of aligning your diet, exercise, work, and lifestyle with the four phases of your menstrual cycle to optimize energy, productivity, and overall health. It recognizes the hormonal shifts that occur throughout the cycle and adjusts activities to support these changes.

The 4 Phases of the Menstrual Cycle

Menstrual Phase (Days 1–5)
Follicular Phase (Days 6–14)
Ovulatory Phase (Days 15–17)
Luteal Phase (Days 18–28)

Cycles and ACL’s

During the ovulatory phase, when estrogen levels peak, women experience increased energy, strength, and endurance, making it an ideal time for high-intensity workouts, strength training, and performance-based activities. 

However, elevated estrogen during the ovulatory phase also decreases ACL stiffness, making it more prone to injury.. Additionally, the hormone relaxin increases ligament elasticity, further contributing to joint instability and injury risk. To stay safe, women should focus on proper form, strengthen the hamstrings and glutes for knee stability, and avoid overexertion.

3. Biomechanics:

Women are more likely to land or pivot with their knees collapsing inward into a valgus position. This inward collapse increases the likelihood of ACL injuries, especially during high-impact or dynamic movements like jumping and cutting.

Additionally, women often have a lower hamstring-to-quadriceps strength ratio. This imbalance reduces the hamstrings’ ability to counteract the forward pull of the quadriceps on the tibia, further increasing stress on the ACL. As a result, the risk of injury becomes significantly higher during explosive movements that require rapid changes in direction or force.

ACL Injuries in Female Skiers and Snowboarders

Skiing and snowboarding are high-risk sports for ACL injuries due to rapid turns, falls, and twisting motions. Women’s increased risk is evident in the statistics:

• Skiing: Studies show that female skiers are 2 to 3 times more likely to sustain an ACL tear than male skiers. One study published in the American Journal of Sports Medicine found that women account for 60-70% of ACL injuries in recreational skiing.
• Snowboarding: ACL injuries are less common in snowboarding than skiing, but women still show a slightly higher risk due to landing mechanics and strength imbalances.

Prevention Strategies for Women

The good news is that ACL injuries are preventable with the right training and awareness. The most important place to start is educating yourself on your hormonal changes which is easiest to do with cycle tracking using an app. Here are a few ideas you can start educating yourself on with regards to preventing future injuries. 

Strength and Neuromuscular Training:

• Focus on strengthening the hamstrings, glutes, and core to support knee stability. Hamstring strength, in particular, helps counteract the strain placed on the ACL by the quadriceps.
• Incorporate exercises that emphasize proper landing mechanics, knee alignment, and dynamic balance. Single-leg hops, lateral jumps, and agility drills can reduce the risk of injury.
• Pre-season ski and snowboard specific training is vital. You wouldn’t jump straight into a rugby game without preparation. The demands of winter sports on your body are high and just because it is recreational, don’t be fooled into thinking you don’t need to prepare your body for what’s to come. Next season: sign up for our pre-season training programmes. We have many options available for everyone. 

Flexibility and Mobility:

• Stretching the hips, quads, and calves improves movement patterns, reducing stress on the knees.

Equipment Fit:

• For skiers and snowboarders, proper fitting of boots and bindings is critical to prevent awkward falls and twisting motions that often lead to ACL tears.

Hormonal Awareness and Cycle Syncing:

• Women should consider aligning their training and skiing activities with their infradian rhythm to optimize performance and minimize injury risk. For example, avoid high-risk movements during the ovulatory phase when ligament laxity is at its peak, and prioritize stability work during the luteal phase when coordination may be reduced.
• Apps and tools that track menstrual cycles can help women plan their activities more effectively and stay in tune with their bodies.
• I have found cycle syncing has helped a lot of women (including me) be kinder to themselves during periods where their body is in a state of rest and recovery. This is important in syncing with your hormones and pushing through at 100% doesn’t mean you’ll come out the other side stronger. We have a lot more power in understanding and respecting the ebbs and flows than most realise. Which leads me to the final point…

Rest and Recover

• Overtraining or ignoring signs of fatigue can increase injury risk. Prioritize rest days, get adequate sleep, and incorporate recovery activities like stretching, foam rolling, massage or using the Normatec Compression Leggings to keep your muscles and joints healthy. I know this is particularly difficult when you’re short on time in the snow and you’re addicted to the pow smacking you in the face. 

Conclusion

Women’s higher susceptibility to ACL injuries comes down to a combination of anatomical, hormonal, and biomechanical factors. The infradian rhythm and the hormonal fluctuations throughout the menstrual cycle play a significant role, making cycle syncing a valuable tool for reducing injury risk and enhancing performance. Sports like skiing and snowboarding, which involve dynamic and high-risk movements, amplify this vulnerability. However, with targeted strength training, proper technique, and an understanding of the menstrual cycle’s phases, women can significantly reduce their chances of injury. Whether you’re enjoying the slopes in Niseko or training off the mountain, prevention and syncing with your natural rhythm are key to keeping your knees—and your ACLs—healthy.