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Are ACL Injuries Really More Common for Females?

It was just another day on the volleyball court for high school athlete Jelena Bojic, as she dove for the ball in the middle of an intense game. It was a play Jelena had made thousands of times before, but this time was different. This time, she heard a pop and felt an intense burst of pain. Jelena looked down, expected to see a bone popping out of her skin, instead she saw nothing. She figured she had just tweaked her knee and the pain would go away on its own. Jelena continued to play, but the next morning her knee had swollen to almost double its size and she knew something was wrong. She had injured her ACL.

Then there’s Sandra Bojic, Jelena’s sister, who was a star basketball player for the her high school’s team. She doesn’t remember a specific incident where she heard a pop or felt an intense burst of pain, but recalls that it gradually became harder to play as she began experiencing increasing pain and weakness in her knee.  She went to dozens of doctors who told her nothing was wrong and encouraged her to keep playing basketball.  But after the pain and weakness had become intolerable, she went to a specialist who informed her she was suffering from an ACL injury.

Four more ACL injuries happened to other female athletes at the same high school that year.  That’s when Lilly Bojic, Sandra and Jelena’s mother and the CEO and physical therapist at Lilly Physical Therapy, decided to get serious about sports injury prevention and pain relief for female athletes.

The information she found was shocking:

-ACL injuries are the most common cause of permanent disability in female high school athletes, accounting for up to 91% of season-ending injuries. In the United States, 20,000 to 80,000 high school female athletes experience ACL injuries each year.  -Collegiate females have a 1 in 10 chance in tearing their ACL-Women are 4-6 times more likely than men to tear an ACL.What is an ACL and Why Are Women More Prone to Injury?

Sports that were traditionally the domain of males have seen a significant rise in female athletes in recent years — and with that comes a significant rise in female athletes with knee-related injuries.  “We are seeing an increased number of adolescent ACL tears, especially in our young female athletes,” says Dr. Charles Popkin, an orthopedic surgeon and sports medicine physician at both NewYork-Presbyterian/Lawrence Hospital in Bronxville.  “Current studies indicate that on average one girl on every high school varsity sports team in the United States will tear an ACL during the upcoming fall season.”

Lilly found, through intensive research, that there are basic gender differences that help to explain why females are so much more likely to tear an ACL than males:

  • First, women tend to have an imbalance in the strength ratio between with quadricep muscle (giant muscle in the front of the leg bone or femur) and their hamstring muscle(muscle behind the leg bone or femur). A female athlete is more likely to use their quadricep muscle to slow down from a sprint thus causing instability in the knee. A male athlete is more likely to decelerate using his hamstring to absorb the change in speed. This slight difference provides an inherent protection to the ligaments of the knee.
  • Next, doctors have studied videos of athletes in motion and identified that four common motor components occur when improper body mechanics happen and when the center of the body mass is outside the base of foot support. On video sequences of actual ACL injuries these four common things are examined:
  1. As the at-risk female athlete lands, her knee buckles inward
  2. The injured knee is relatively straight
  3. Most if not all of her weight is on a single lower extremity, and
  4. Her trunk tends to be tilted laterally
  • Some professionals think women are more likely to have an ACL injury because of the differences in the amount of circulating hormones such as estrogen and realxin. Both of these hormones give ligaments strength and flexibility and the fluctuations of the hormone may influence the function of the nerves and muscles.
  • Finally, doctors continue to study the effect of soft and harder playing surfaces, use of footwear such as cleats vs. sneakers as well as the anatomical differences between men and women (women tend to have broader hips, are  more flexible,  to understand the higher rate of women with an ACL rupture.

Whether you are male or female, it is important to know what to do to prevent injury and avoid the long period of rehab following the injury. Here are 6 ways to help prevent a torn ACL:

  1. Preseason LE strength and endurance training:

It is important to come into your athletic season prepared. Training should begin at least four weeks before beginning sport specific exercises and should include endurance training and leg strengthening exercises.

  1. Hip strengthening:

Strength of the glutes and hips help control the motion of the femur and decrease stress and shear on the knee joint itself.

The following link shows a video of US Women’s soccer player, Ali Krieger demonstrating some strengthening exercises.


  1. Train alignment and mechanics:

You should evaluate the alignment of your knee while doing squats, lunges, and landings.   As an athlete you should try to be aware of proper mechanics and try to do these motions without allowing the knee joint to stray toward the midline.

  1. Adequate recovery, rest, nutrition:

Adequate sleep and rest are imperative to allow healing and to help prevent injury. Muscles require adequate recovery time in order to become stronger. Injuries occur more often when athletes and/or their muscles are fatigued.

  1. Agility training:

It is important to train speed, sharp cutting, and landing motions as theses motions occur frequently in sports and can lead to knee injuries.

  1. Balance training:

Single leg balance training improves proprioception (the “feeling” in a joint that tells you where it is in space) and strengthens the overall leg muscles.

 Injury reduction programs, which include these 6 key elements, have been shown to reduce incidence of ACL tears.

In the end, an ounce of prevention is worth a pound of cure. “As surgeons, our job is continually to look for innovative ways to repair and reconstruct the ACL ligament, but our greatest reward would be to keep these injuries from happening in the first place,” says Dr. Charles Popkin.

How Lilly Physical Therapy Can Help:

Our therapists are internationally trained professionals and experts in manual therapy that hold special interest in sports injury prevention and treating sports related injuries. Dr. Lilly or Dr. Sophie will evaluate and treat any limitations in range of motion and strength that put you at risk for injury.  At Lilly PT, we offer a detailed evaluation to determine the level of potential risk caused by an injury, followed by a combination of therapeutic interventions that include stretching, strengthening, manual work, bracing, taping, postural correction, plyometrics, and education regarding injury awareness and injury avoidance techniques.

Benefits include decreased pain, improved function, speed, agility, and increased performance. Most patients report noticeable improvement within one week!!