Females Are More Likely Than Males To Tear Their ACL – Here’s Why!

Females are 2-10x More Likely To Tear Their Anterior Cruciate Ligament (ACL) than males!

Why is this and how can we help?

The ACL is a ligament located in the knee joint. It’s job is to prevent the shin bone (tibia) from moving forward and turning inward on the thigh bone (femur). It is most commonly torn in non-contact situations- when a player attempts to change directions, pivot, or during jumping and landing. After the ACL is torn and surgery is performed, recovery can take anywhere from 6 months to a year before return to play. Since the recovery is so long, it would be beneficial if this injury could be prevented.
Females are 2-10x more likely to tear their ACL then males. This is due to knee biomechanics, neuromuscular control, cognitive fatigue and hormones. To lower the risk of ACL tears clinical interventions could focus on neuromuscular control and/or cognitive fatigue as these are area’s we can control.

Neuromuscular Control

There are three main differences in neuromuscular control in males versus females, that are believed to contribute to higher rates of ACL tears.

1. Females are not able to stiffen the musculature around their knee to the same degree as males. Studies show that males have a higher percent increase in stiffness when comparing the relaxed knee musculature to the ‘on’ knee musculature. This means that females rely more on their bones and ligaments for support, placing more stress on the ACL and increasing the chance of injury.

2. When females find themselves in a vulnerable position for the ACL they turn on different muscles then males. The quadricep muscle, on the front of the thigh, pulls the shin bone forward when turned on. The hamstring muscle, on the back of the thigh, pulls the shin bone backwards. The ACL tears when the shin bone moves forward, therefore when in a dangerous position, the hamstring muscle can help protect the ACL by preventing the shin bone from moving forward. When in a dangerous position, males turn on their hamstring muscle first, females do not. Instead they turn on their quadricep muscle putting them at increased risk. Not only do females turn on the wrong muscle first but they also tend to have stronger quadricep muscles then hamstrings.

3. Lastly when performing pivoting, landing and cutting movements females have knee positions that are more dangerous then males. Female’s allow their knees to collapse towards the middle. In this position the knee is in a position more likely for the ACL to tear and therefore puts them at a greater risk.

Cognitive Fatigue

Studies have shown that cognitive fatigue leads to poor landing posture of the knee and therefore will put athletes at a greater risk of non-contact ACL injuries. Cognitive fatigue is a decrease in a person’s mental abilities. This would include their ability to focus, process information (where the ball is, where the other players are, etc.) and make effective and smart decisions on what their next action is. As the brain’s ability to perform with good cognitive efficiency decreases, proper knee position during jumping and cutting tasks also becomes affected.

What Can We Do About It?

Training programs that work on strength, plyometrics, dynamic balance and body awareness have been shown to decrease the risk of non-contact ACL tears in female athletes. These programs aim to improve knee position during cutting, pivoting and jumping and correct the musculature imbalances that put female athletes at greater risk.
At Shift we have the ability to work on cognitive processing using a system called Neurotracker. This allows athletes to train their mental stamina and therefore decrease their risk of cognitive fatigue. This will not only help their sports performance, but also decrease their risk of injury.
For more information on NeuroTracker for performance, please click here.