(HealthDay News) — When a teen athlete is tired, their risk of suffering a common knee injury rises, a new study suggests.

The anterior cruciate ligament (ACL) connects the thighbone to the shinbone, at the knee. When the ACL is overstretched or torn, it can cause swelling, instability and pain. It can also lead to high treatment costs because it may require surgery or physical therapy.

The new study included 85 athletes, average age about 15, who participated in track and field, basketball, volleyball and soccer.

In controlled assessments, “44.7 percent showed an increased injury risk after high-intensity aerobic activity,” said study author Dr. Mohsin Fidai, from the Henry Ford Health System in Detroit.

“Additionally, 68 percent of those studied were identified as having a medium- or high-risk for injury following the activity, as compared to 44 percent at baseline,” Fidai added in a news release from the American Orthopaedic Society for Sports Medicine (AOSSM).

Fourteen of 22 athletes with over 20 percent fatigue showed an increased ACL injury risk. The study also found that female athletes and those over age 15 were more likely to have an increased risk.

“While ACL injury prevention programs are commonly used now, a decrease in injury numbers has not followed suit,” Fidai noted. “We hope this study helps advocate for ACL injury prevention training programs to incorporate fatigue-resistance training and awareness by coaches, trainers and physical education teachers.”

The study was scheduled for presentation Thursday at the AOSSM’s annual meeting, in San Diego. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.

More information

The American Academy of Family Physicians has more on ACL injury.

SOURCE: American Orthopaedic Society for Sports Medicine, news release, July 5, 2018

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