Is There a Time During My Menstrual Cycle When My ACL Is Most at Risk?
As Dr. William Sterett, a board-certified orthopedic surgeon and sports medicine specialist at Vail-Summit Orthopaedics & Neurosurgery in the athletic community of Vail, Colorado, I’ve worked closely with countless female athletes. One question that’s come up more frequently in recent years is this: Does my menstrual cycle affect my risk of tearing my ACL?
The short answer is yes—there is growing evidence that hormone fluctuations throughout the menstrual cycle can influence ligament laxity and neuromuscular control, which in turn may increase the risk of ACL injury during specific phases.
Let’s break down what the science says, when the ACL might be most vulnerable, and what you can do to protect your knees throughout the month.
How Hormones Affect the ACL
The anterior cruciate ligament (ACL) contains hormone receptors that respond to fluctuations in estrogen and progesterone—two key hormones that vary significantly during the menstrual cycle.
Estrogen, in particular, has been shown to affect collagen metabolism and increase ligament laxity. When estrogen levels are elevated, the ACL may become slightly more flexible or “loose,” reducing its ability to stabilize the knee during high-impact or pivoting movements.
When Is the ACL Most at Risk?
Research suggests that the ACL may be most vulnerable during the pre-ovulatory phase, which typically occurs around days 10 to 14 of a standard 28-day cycle. This is when estrogen levels peak, and progesterone remains low.
During this window:
Ligaments may be more lax
Neuromuscular control may be slightly impaired
Reaction times and joint stability may decrease—especially during explosive movements like jumping or cutting
This doesn’t mean that every female athlete will experience problems during this phase, but it is a time when the body may be less equipped to handle certain physical demands.
What Can You Do About It?
While you can’t change your natural hormone cycle, there are steps you can take to protect your ACL:
1. Track Your Cycle:
Understanding when you're entering high-risk phases can help you adjust your training and competition schedule. Apps that track hormonal changes and symptoms can be a useful tool for female athletes and their coaches.
2. Prioritize Neuromuscular Training:
Programs focused on balance, proprioception, and movement control can reduce your risk of dynamic knee valgus (the inward collapse of the knee), which is commonly linked to ACL tears.
3. Modify High-Risk Activities:
During the pre-ovulatory phase, consider reducing high-intensity plyometrics or aggressive cutting drills. Instead, focus on technique, strength, or recovery work.
4. Communicate With Your Medical Team:
If you’ve had an ACL injury in the past or are at high risk due to anatomical factors, let your healthcare team know. A personalized injury prevention plan may include physical therapy, bracing, or performance modifications based on your cycle.
Hormones Are Part of the Picture—Not the Whole Story
While the menstrual cycle can influence ACL risk, it’s just one piece of a complex puzzle. Dr. William Sterett takes a comprehensive approach to injury prevention—looking at biomechanics, strength, technique, and yes, even hormones.
If you’re a female athlete with concerns about ACL injury or performance fluctuations throughout your cycle, request a consultation. Together, we can tailor a plan to help you stay strong, stable, and in the game—all month long.
