An intriguing study published in the Scandinavian Journal of Medicine & Science in Sports suggests that car horns or a nearby shout have been linked to an increased risk of knee injury.
For their study, researchers hooked 18 men and 18 women in their 20s up to a machine designed to capture leg spasm and movement. Participants were asked to resist downward pressure from a mechanical arm, but half the group was subjected to a loud beep prior to the downward pressure, while the other half heard no sound. Researchers say the sound was equivalent to the revving of a loud motorcycle engine.
Interestingly, those participants in the noise group exhibited significantly more muscle stiffness during the resistance and bend tests compared to those in the no beep group. Researchers also noted that muscle activity and joint stiffness reduced as the startled response subsided.
Researchers wrote that higher initial stress followed by markedly reduced stiffness likely indicates a disturbance in neuromuscular control that can lead to abnormal stress and unintentional injury. Considering there are an estimated 250,000 ACL sprains and tears in the US every year, it’s not unreasonable to suggest that at least some of them occurred as a result of a loud or unexpected noise.
The researchers noted that the beep used in the study may not compare to loud sounds during athletic competitions, and an athlete can reasonably expect to hear a whistle or a buzzer at certain intervals during the matchup. Instead, they say car horns, unexpected sirens or a nearby shout are the most likely cause of noise-induced injuries.
Dr. Silverman comments
This study is interesting because it focuses on how our brain’s reaction to an unexpected occurrence affects the rest of our body. A sudden jolt or flinch is your body’s way of going into “defense mode,” but if you’re running or playing a sport, that instantaneously reaction could cause major issues.
Related source: Wall Street Journal