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JAG Physical Therapy

ACL Injuries & Female Athletes


The prevalence of Anterior Cruciate Ligament tears in athletics has become an epidemic, especially within the female athlete population. We cringe when we--as athletes, parents, coaches or health care professionals--watch a female athlete go down on the field holding her knee. In the United States alone, studies have shown that upwards of 80,000 high school-aged, female athletes will suffer from an ACL injury, with most of those occurring in soccer and basketball.  But why do females suffer nearly  ten times more ACL injuries than males?

Why Are Women More Likely to Tear Their ACL?

Although science has yet to prove one theory over another, there are several factors that this prevalence may be attributed to:

  • Greater Q angle- Women have a greater Q angle than men. The Q angle is the angle at which the femur meets the tibia. This is wider in women due to the wider pelvis that begins to develop during puberty (to accommodate for potential child birth.) This greater angle leads to the femur facing inward, while the tibia maintains its forward facing position. Genu valgum, or the ‘knock knees’ which develop from the greater Q angle, place a concentrated force on the ACL during each twist and turn of the knee. This leads to an increased risk of anterior knee pain and ACL injury.
    • Biomechanical differences exist  in running and landing techniques (i.e. knees falling in) as well, due to muscular imbalances and increased body weight.
  • Puberty- Before the onset of puberty, the playing field is equal when it comes to knee injuries in boys and girls. So what happens during and after puberty that leaves girls so susceptible to injuries?
    • Testosterone Production- As a young male goes through puberty, his body is producing the hormone testosterone. This is not only responsible for a deeper voice and facial hair, but is also responsible for increases in height, weight and muscle mas. Females, though they produce small amounts of testosterone during puberty, do not typically produce enough to keep up with the demand from growing muscles. This can leave females with muscular imbalances: in particular, between the hamstrings and quadriceps. This leads to increased risks of knee pain and ACL injuries.
    • Weight Differences- During puberty, both males and females will gain lean muscle mass. Females often retain and gain body fat, while males tend to lose body fat. This addition of muscle mass and body fat can place additional weight on the female body’s  joints, potentially leading to strain and/or failure like an ACL tear. 
  • Female Hormones- Studies have shown that female hormones produced during the menstrual cycle- estrogen, progesterone, relaxin- allow for greater flexibility and laxity of muscles, tendons, and ligaments. If the soft tissue structures surrounding the knee are lax, a tremendous amount of stress may be placed on the ACL when trying to compensate for the other structures. This stress can lead to failure of the ACL.

As a female, how do I know if I am at risk?

A simple test which can be performed by the athlete--and monitored by a coach or parent-- is a two-legged jump test. The athlete begins by standing on a step or bottom row of a bleacher, and is instructed to jump off and land on her two feet. No instruction should be given in terms of how she should land, other than “on two feet.”  If the athlete is strong in her core, hips and thigh muscles, she will land with her feet slightly apart. Her knees will be slightly bent and facing forward. If there is muscular weakness or imbalance, the athlete will land the jump with one or both knees falling or facing inward, and will be less stable overall.

If we can’t prevent the injury, can we reduce the risk?

Absolutely! Over the past 10 years, a tremendous amount of focus has been placed on ACL injury reduction programs. Although we are more knowledgeable and have seen great advancements, there is no possible way to fully prevent an ACL injury. However, it is encouraging to know that the implementation of stretching and strengthening programs can help. The Lower Extremity Strengthening System (L.E.S.S) offered at JAG Physical Therapy can help reduce these incidents by more than 50-60%. These types of programs are evidence-based, and consist of lower extremity and core strengthening exercises, lower extremity stretches, and instruction in proper mechanics during running, jumping and landing.

Programs similar to this are also being offered at local gyms and physical therapy clinics, and can be seen being implemented into warm-up routines at many schools and athletic clubs. Now that we know the science, let’s take advantage of the help available. We can ensure all athletes, and females in particular, have access to programs which help reduce their risk of injury, allowing them to continue playing the games they love!