The sound of a pop in the knee, swelling of the knee, and limited knee movement for an athlete in high-intensity contact sports like basketball, baseball, and football are symptoms associated with an anterior cruciate ligament (ACL) injury. In the United States, 250,000 ACL injuries occur every year, with estimated costs for 15- to 24-year-old male and females athletes at $1 billion annually in the nation (not including diagnosis and rehabilitation), according to the University of Minnesota. The recovery time for an ACL tear is usually six to 12 months away from the sport, with a high risk of reinjury upon return to the sport. Despite men and women partaking in the same sports at the same physical level, young women are two to eight times more likely than young men to experience ACL injuries, says the National Institutes of Health and the Friends of the National Library of Medicine. However, women can prevent their chances of an ACL injury by using a different landing strategy, according to two new studies.
Findings of these two studies published online in the Journal of Athletic Training showed that, while both men and women tended to land stiffly in a series of jumping exercises, women were 3.6 times more likely to land in a knee valgus, or a “knock-kneed” position, that may contribute to the gender disparity in ACL tears. The researchers examined the landing strategies of 82 physically active men and women by using motion analysis software. Men and women were both found to use their quad region in the same way to land, but women tended to put stress on the knee when they landed in a knock-kneed position, which was found to put them at higher risk of ACL tears.
“We know that people who hurt themselves tend to look stiff when they land and that the combined ‘knee loading’ from multiple directions is likely causing the injury event,” said Marc Norcross, lead author of the study and assistant professor of exercise and sport science at Oregon State University.
Speculations as to why athletic women land this way consider the combination of body type and landing techniques. Norcross believes its basic biology: women have wider hips, making it more likely that their knees will be brought together after landing their initial jump.
Women are anatomically different than men, which can account for why they are more prone to ACL injuries. According to the Hughston Clinic, women have less developed thigh muscles, which make the knee more reliant on the ligaments for stability. And so, the ACL must be the central stabilizer of the knee. During high-intensity sports, the small ACL is not able to handle the added pressure it receives, causing it to tear.
The two studies call upon athletic trainers to look for an effective way to incorporate injury prevention into team warm-up activities that improve landing techniques among athletes. Norcross’s future research endeavor involves a project that will concentrate on high school athletes and how to include injury prevention.