Women and Knee Injuries

Why Are Knee Injuries Common in Female Athletes?

As the number of women participating in competitive athletics has dramatically risen over the past several decades, there has been a corresponding increase in the volume of female athletic injuries. This has led to an increased focus on the study of female athletic injuries and mounting evidence that there are distinct differences in the types, prevalence, and causes of sport injuries that men and women suffer.

One such difference is in the knees. Dr. Jennifer Baima, a former student athletic trainer at Notre Dame, a clinical instructor at Harvard Medical School, and a physiatrist who specializes in treating female sports injuries as head of the Women and Sports Medicine Program at Brigham and Women’s Hospital, discusses below why women are more at risk for knee injuries and what they can do to lessen that risk. Dr. Baima also describes this issue in her recent book, Biographies of Disease: Sports Injuries, as part of “an overview of the common injuries sustained by athletes of all ages and levels of competition.”

What are the anatomical factors that increase a woman’s risk of suffering certain sports-related knee injuries?

There are a variety of anatomical differences between men and women that could account for why women are much more likely to experience anterior joint pain or an anterior cruciate ligament (ACL) tear as a result of athletics.

Overall, a woman’s body is designed for flexibility and a man’s body is designed for strength. Correspondingly, a woman tends to have weaker quadriceps and hamstring muscles. This disparity places women at a disadvantage, as these muscles serve to help stabilize the knee and absorb shock when sharply cutting or jumping and landing during athletics.

However, recent research suggests that the difference between a man and a woman’s hip structure may be the most significant reason why women experience more knee injuries. A woman’s wider hips cause her to land in a more “knock-kneed” position – angled in from hip to knee and angled out from knee to ankle - to maintain balance, whereas a man’s legs tend to be straighter when he lands. This angular positioning of the legs produces a tremendous strain on the knees.

Are there any non-anatomical factors that could affect a woman’s risk of knee injury?

The failure to consume an adequate amount of calories is one non-anatomical factor that could substantially increase a woman’s risk of athletic injury. This lack of energy intake is part of the Female Athlete Triad, three interrelated female health issues – low energy availability, altered menstruation and osteoporosis – thought to be a significant contributor to a woman’s risk of athletic injuries. Low energy availability is caused by the tendency of female athletes to intake less calories than what would be desirable for their level of activity (sometimes exacerbated by or leading to eating disorders). This lack of energy availability can lead to a suppressed menstrual cycle and/or osteoporosis. A critical aspect of the Triad is that it begins with an issue that can be controlled – energy intake.

Are there particular sports that carry a greater risk for knee injuries in women?

Sports that require a great deal of cutting or jumping, such as basketball, soccer, or skiing, significantly heighten the risk of knee injuries in women. According to National Collegiate Athletic Association (NCAA) research, female basketball players are four times as likely to suffer from an ACL tear as male basketball players.

What can be done to reduce knee injuries in women?

One important thing that women can do to reduce their risk for injury is to avoid focusing entirely on one sport throughout the year. Switching sports from season to season gives specific body parts a better chance to recover.

Another strategy is to develop a training regimen that not only focuses on strengthening the quadriceps and hamstrings, but also teaches women to land with their knees facing forward (Figure 1), not inward (Figure 2).

Lastly, women need to focus on consuming a sufficient amount of calories. This will help to prevent athletic injuries and a multitude of other health issues.

Figure 1  Photos courtesy of Diane O’Brien	Figure 2