In a world where people are more likely than ever to wear GPS watches to work, a common reaction to the new Garmin Watch Sport is that of an “overly-sensitive” muscle.
But, a new study suggests, the reaction might not be the case.
In fact, research suggests the muscles involved in the sensation of pain are not really that sensitive to movement.
“We don’t know why the muscles are sensitive to motion.
We think that the brain might use these signals to generate the sensation,” says researcher Jodie Bauch of the University of Sydney in Australia.
But Bauz thinks there might be something else going on.
She and her colleagues are looking at what happens when people are unable to move their body.
For example, they want to know if the muscles of people with chronic knee pain (knee pain) are similar to those of people without knee pain.
Their study, published in the journal Nature Neuroscience, is the first to show that the muscles in people with knee pain are more sensitive to changes in motion than are those in people without it.
They’re also the first research to examine whether the same brain mechanisms can explain how people with pain with varying degrees of movement might respond to a perceived pain in their knee.
“If we can’t figure out how the muscles feel in the absence of movement, what does that tell us about the brain?” says Bauvans Professor of Neuroscience at the University, who was not involved in this research.
“That’s where the idea of proprioception comes in.”
Bauch and her team tested their subjects’ ability to move in a range of environments using a virtual-reality headset called the Leap Motion.
The team trained them to perform various tasks in the virtual world and measured their movement using an accelerometer that measured their heart rate.
“They’re not just measuring their movements, they’re also measuring their heart rates,” says Baus.
“And then the next day, the next morning, they did the same activity again.”
Using the same accelerometer, the researchers found that the participants who had no knee pain were less able to control their body in a VR environment than those with pain.
And if they were unable to control themselves, they were also more likely to use the headset to check their breathing rate.
So, when it came to feeling pain in the knee, they could have a “threshold” of pain, Baush says.
“They were getting the same signals from their brain to their muscles as they were from the muscles they were working on,” she says.
“If you can’t control your body in the presence of pain then you’re going to be a lot more likely just to use your hands.”
And when people with joint pain experienced pain in a virtual environment, they tended to use the Leap motion more frequently, she says, to make sure they were not overdoing it.
“The more they used the Leap, the more likely they were to be able to use their hands,” she adds.
Bauz’s team found that if a person was unable to use any of the virtual-world tasks, they also experienced less pain.
This is the first study to show an effect of movement in a physical environment on the brain.
But the effect of the activity itself on the human brain is not entirely clear.
The researchers also found that people who had knee pain experienced greater pain than those without.
“What we’re seeing is that the activation of the spinal cord is associated with pain,” says Baus.
Baus says that this might be due to the fact that the pain is connected to a nerve.
“So if the pain doesn’t trigger a release of that nerve, then the pain remains for a long time.”
The effect of motion on the nervous system is also a bit unclear.
“The results are not conclusive.
There are still some unknowns,” says the University’s Professor of Neurology, Dr Amy Bove.
If the effects of motion are mediated by the spinal chord, it means that the effects would be different for different types of movement.
It’s also unclear if the effect was due to changes to the spinal nerves or the way they respond to the activity.
As the researchers have now found, there are differences in the response of the brain to different types and degrees of pain in people who have knee pain and those without, and it’s also possible that these differences in response might be related to how different the participants are.
Dr Bauwch says there are also potential ways to interpret this research, and what we might learn about the neural basis of pain is just the beginning.
While the research in this paper could be used to help people with some knee pain manage their pain better, it’s far from clear how to best help them manage the