Women are more prone to knee injuries than men, and the findings of a new study suggest this may involve more than just differences in muscular and skeletal structure – it shows that males and females also differ in the way they transmit the nerve impulses that control muscle force.
Scientists at Oregon State University found that men control nerve impulses similar to individuals trained for explosive muscle usage – like those of a sprinter – while the nerve impulses of women are more similar to those of an endurance-trained athlete, like a distance runner.
In particular, the research may help to explain why women tend to suffer ruptures more often than men in the anterior cruciate ligament of their knees during non-contact activities. These ACL injuries are fairly common, can be debilitating, and even when repaired can lead to osteoarthritis later in life.
More study of these differences in nervous system processing may lead to improved types of training that individuals could use to help address this issue, scientists said.
“It’s clear that women move differently than men, but it’s not as obvious why that is,” said Sam Johnson, a clinical assistant professor in the OSU School of Biological and Population Health Sciences.
“There are some muscular and skeletal differences between men and women, but that doesn’t explain differences in injury rates as much as you might think,” Johnson said. “No one has really studied the role of the nervous system the way we have in explaining these differences, specifically the way sensory information is processed and integrated with motor function in the spinal cord.”
In this study, just published in the European Journal of Applied Physiology, the scientists found that most aspects of spinal motor control and rapid activation of muscles were similar in 17 men and 17 women that were examined – with one exception. Men had a higher level of “recurrent inhibition,” which is a process in the spinal cord that helps select the appropriate muscle response.