Female Athletes, ACL Tears & the Menstrual Cycle: What’s the Connection?

A split-second change of direction.

A hard landing after a jump.

One foot plants, the body turns, and suddenly the knee gives way.

For an athlete, an ACL tear can change an entire season. Training stops. Competition disappears. Rehabilitation begins.

Female athletes face a higher rate of ACL injuries than male athletes in several sports, particularly those involving jumping, cutting, pivoting, and rapid changes of direction.

But why?

Sports scientists have spent years studying the question. Strength, biomechanics, landing technique, anatomy, neuromuscular control, previous injuries, and training demands can all influence ACL injury risk.

And now, researchers are asking another question:

Could the menstrual cycle play a role too?

What Does the Menstrual Cycle Have to Do With the Knee?

The menstrual cycle isn’t simply a few days of bleeding.

Hormones such as estrogen and progesterone fluctuate throughout the cycle. Researchers have investigated whether these hormonal changes can influence factors that matter to athletic movement, including joint laxity, neuromuscular control, and how the body responds to physical stress.

Some studies have reported changes in knee or ACL laxity during different phases of the cycle.

That sounds important.

But there’s a catch.

Changes in laxity don’t automatically mean an athlete is going to tear her ACL.

Research examining menstrual-cycle phase and ACL injury risk has produced inconsistent findings. Current evidence isn’t strong enough to identify one specific phase as a universal “high-risk” period for ACL injuries.

So, if you’re an athlete looking at your period-tracking app before practice, don’t assume it can tell you whether your ACL is in danger.

It can’t.

The ACL Doesn’t Know You’re Having a Bad Training Day

Think about what happens during competition.

You’re sprinting toward the ball.

An opponent changes direction.

You plant your foot and cut.

Or you jump for a rebound and land while another player is closing in.

These movements happen quickly, often in fractions of a second.

Your ACL is part of a larger system that helps keep the knee stable during these demanding movements. The way your muscles fire, how you control your landing, your balance, coordination, fatigue, and the forces placed on the knee all matter.

That’s why ACL injury prevention can’t be reduced to one hormone or one phase of the menstrual cycle.

Your cycle may be one piece of the puzzle. It isn’t the whole puzzle.

Why Female Athletes May Face Greater ACL Risk

The difference in ACL injury rates between male and female athletes is complex.

Researchers have identified several potential contributors.

Biomechanics can influence how an athlete lands, decelerates, and changes direction. Strength and neuromuscular control affect how the body manages those forces. Anatomical differences can also influence knee mechanics.

Then there’s the reality of sport itself.

Athletes don’t perform movements in controlled laboratory conditions.

They compete while accelerating, stopping, jumping, reacting to opponents, changing direction, and sometimes playing through fatigue.

That combination of factors is why ACL injury prevention needs to look at the whole athlete, rather than searching for one explanation.

Should Athletes Change Training Around Their Cycle?

This is where things can easily become overcomplicated.

At the moment, there isn’t enough evidence to say that female athletes should avoid certain movements, reduce training, or completely change their programs because they’re entering a particular phase of their menstrual cycle.

Instead, athletes can use cycle tracking as another way of understanding their individual responses to training.

Maybe your energy feels different during certain days.

Maybe you notice more fatigue.

Maybe a hard training session feels harder than usual.

Maybe your recovery doesn’t feel quite the same.

Those patterns can be useful information.

But they shouldn’t become restrictions.

Awareness is useful. Fear isn’t.

What Actually Helps Protect the ACL?

Whether you’re in the first week of your cycle or the last, the fundamentals of athletic preparation still matter.

Build strength

Strength training helps athletes develop the capacity to handle the forces involved in sprinting, jumping, landing, and changing direction.

Train how you move

ACL prevention isn’t just about being strong in the weight room. Athletes also need to practice controlling movements such as landing, decelerating, and cutting.

Improve neuromuscular control

Sport is unpredictable. Your body has to react quickly when an opponent changes direction or a landing isn’t perfect. Training balance, coordination, and movement control can help athletes prepare for those demands.

Manage fatigue and training load

A tired athlete may not move the same way as a fresh athlete. Training load and recovery therefore matter, not just for performance, but also for maintaining movement quality.

Don’t ignore previous injuries

A previous knee injury can affect movement patterns and future injury risk.

Returning to sport should involve appropriate rehabilitation and progression rather than simply waiting until the pain disappears.

These principles aren’t specific to one phase of the menstrual cycle.

They’re part of being a well-prepared athlete.

Listen to Your Body Without Limiting Yourself

There is a difference between paying attention to your body and becoming afraid of it.

If you notice that your energy, recovery, or training response changes at certain points in your cycle, track it.

Look for patterns.

Talk to your coach, athletic trainer, physiotherapist, or other qualified professional if something consistently affects your training.

But don’t let a calendar convince you that you’re fragile.

Your menstrual cycle doesn’t determine whether you will tear your ACL.

And having a period doesn’t mean you need to sit out of practice.

The Bigger Picture

The conversation around female athletes and the menstrual cycle is important but it needs to be approached carefully.

Researchers are still investigating how hormonal fluctuations may influence factors such as knee laxity, neuromuscular control, and movement.

What we don’t have yet is enough evidence to say:

“This is the week female athletes are most likely to tear their ACL.”

Sports are far too complex for that kind of prediction.

A better approach is to look at the athlete as a whole.

Build strength.

Practice quality movement.

Train for the demands of your sport.

Manage your workload.

Recover properly.

Pay attention to your body.

And if your knee hurts, swells, gives way, or feels unstable, don’t blame it on your cycle and push through. Get it assessed.

The goal isn’t to make female athletes afraid of their hormones.

It’s to give them better information about their bodies so they can train smarter.

Because protecting your ACL isn’t about finding one dangerous week.

It’s about building an athlete who’s ready for the whole season.