Investigators introduce tool to identify female athletes at high risk for knee injury

A group of Danish researchers reported that screening the knee muscles of noninjured female athletes with electromyography (EMG) can determine if they are at a high risk for an anterior cruciate ligament (ACL) rupture.

The study, published in the October issue of the American Journal of Sports Medicine, is reportedly the first of its kind to define a specific muscle group activity that may predispose a female athlete to an ACL injury.

“An ACL injury for a female athlete doesn’t just affect her at the moment of injury; a high percentage of female athletes who suffer an ACL injury experience long-term consequences such as osteoarthritis and disability. This is unacceptable,” lead author Mette K. Zebis, PhD, of the Institute of Sports Medicine Copenhagen and the Danish National Research Centre for the Working Environment, said in a press release.

“Our research aimed to evaluate the possible use of EMG recording as a tool for ACL injury risk screening. If we can identify those at risk for the injury, we can help prevent it,” she said.

Researchers used EMG analysis to screen 55 noninjured female athletes as they performed a standardized side-cutting maneuver often used in basketball, soccer, lacrosse and tennis. The investigators selected the common side-cutting movement because a large number of non-contact ACL injuries appear to occur during this maneuver, Zebis said in the press release.

Of the 55 athletes studied, five had lower EMG “signals” in the medial hamstring muscle on the back of their thigh and higher activity in their quadriceps muscle. Those same five athletes experienced an ACL rupture later on in the competitive season.

The investigators also analyzed all subjects’ EMG signals and defined each athlete’s high-risk zone. Ten individuals initially fell into the high-risk zone, with five of the 10 among those who subsequently experienced a non-contact ACL rupture, according to the press release.

The high-risk zone developed by Zebis and her coauthors is a “promising” tool, she said, but further studies using a larger sample size are still needed to standardize neuromuscular screening for determining those in the high-risk zone.

“Our study provides a foundation. Larger studies should be conducted to confirm our suspicions that this screening tool will be a huge asset in preventing future female athletic injuries,” she said in the press release.