Loud, startling noises may increase the risk of knee injury, according to a surprising new study published in the
Scandinavian Journal of Medicine & Science in Sports.
Researchers found honking horns, sirens and other noises can disrupt circuits in the brain that control muscles and ligaments that stabilize the knee, causing people to trip and fall, the
Wall Street Journal reports.
That may explain why buzzers and shouting during sports competitions affect some athletes who normally have good balance and muscular control, they said.
An estimated 250,000 sprains and tears to the anterior cruciate ligament are reported every year in the U.S., according to the Centers for Disease Control and Prevention. Researchers suggest some ACL injuries are likely due to a noise-induced startle response in the central nervous system that results in coordination errors.
The study involved 18 men and 18 women in their early 20s from the University of Delaware whose knees were monitored as they heard a brief, high-pitched beep, about as loud as a motorcycle, through earphones just before bending their knees.
The beep induced a startle response that significantly increases the risk for abnormal stresses on the joint and unintentional injury, the researchers said.
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