Do you startle easily? Do you leap
off your seat every time you hear a door slam? If so, you’d better hope your
vehicle is never rear-ended.
because new research shows that it may not be the impact of the crash that
causes a potential case of whiplash as much as the surprise.
with the Canadian Chiropractic Research Foundation and MEA Forensic Engineers
and Scientists Ltd. Of Richmond, Jean-Sebastien Blouin, an assistant professor
of human kinetics at the University of B.C., discovered that when you’re
startled during a car crash, your neck muscles contract. It could be this sudden
contraction that leads to whiplash.
trying to see if people who develop whiplash injuries have a higher startle
response than people who don’t suffer an injury,” Blouin said Tuesday, the
day his research was published in The Journal of Physiology.
medical science’s understanding of whiplash is far from complete, Blouin says.
Generally speaking, doctors know that it involves an injury to the muscles
and/or ligaments in the neck. But because the neck is such a complex part of the
body, precisely what kind of injury often isn’t known.
know what causes pain in 50 to 60 per cent of patients. But when it comes to the
rest, we don’t know what’s happening,” Blouin said.
fact that our neck muscles contract when we’re startled is something
physiologists have known for some time. It’s just that when they do, its lasts
such a short time – just a few milliseconds – so we barely notice it. And
then when it’s over, there are no lingering after-effects.
what Blouin’s research suggests is that it may be this startle response that
makes the difference between getting whiplash and not getting it. Or getting a
severe case or a mild one.
occurs when a person is struck from behind – usually in a car, but it also has
been known to happen on the hockey rink, when the trunk is pushed forward faster
than the head, Thus, there is a dangerous moment when your neck is being
stretched in a way it shouldn’t be.
neck is thought to move 125 milliseconds after the onset of the trunk motion,”
Blouin says, “And at that time we know the neck is going through a period of
the same time, we see muscle contraction and this muscle contraction is a
response to being startled. And it’s this muscle contraction caused by the
startle that will make things even worse.”
made his discovery by measuring neck responses in 120 people who volunteered to
take part in staged accidents – at speeds of no more than 4 km/h – first in
cars and then in a specially designed device that simulates the effects of being
what he found was that when injuries occurred, they were most severe when the
startle response was greatest.
the question now is, is the injury caused by startling?” Blouin says.
in turn, he adds, suggests that people who are excitable – people who jump
when someone claps his hands or a dog barks- might be more susceptible to
whiplash than people who aren’t.