My sister and I were in a car accident together. We both were stopped by air bags on impact. She came out of it okay, but I have a whiplash neck injury. I've had other neck problems in the past. I wasn't having any problems at the time of the accident. Is it possible that I was injured because I had neck problems before?

It's a good question, but it's impossible to say. Some doctors might call your previous neck problems a "pre-existing condition." Others may see these as two separate episodes.

A recent study of neck pain from Australia showed how muscle activity changes after a neck injury. The painful muscles stop contracting and other nearby or opposite muscles increase their activity instead.

Did the change in muscle activity come after the neck injury or was it present before the neck pain started? Some scientists think it's possible that altered muscle coordination already present is what causes the neck pain after a minor injury. More study is needed to iron this one out.