Q: I'm seeing a physiotherapist for neck pain from a car accident two months ago. She says I have "trigger points" that have to be released before I'll get my neck motion back. Is this a normal problem to have after a whiplash injury or am I unusual?

A: Up to 40 per cent of individuals who hurt their necks in a car accident end up with chronic pain and loss of neck motion. It's likely that trigger points (TrPs) are a large part of the picture both in cause and effect. We'll explain what that means.

First, trigger points (TrPs) are hyperirritable spots in the muscle caused by muscle immobilization (e.g., in a cast or splint or in response to pain after an accident) or overuse (repetitive motion). When active, these points create painful muscles and limited range-of-motion. Trigger points develop along with whiplash-associated disorder as a result of something called central sensitization.

Central sensitization is a hyperexcitability of the central nervous system. In other words, when present, TrPs "revv" up the engine of the nervous system and it doesn't slow down when the foot is taken off the accelerator. But there may be more to it than that as some research has shown a bidirectional mechanism. Input from TrPs to the nervous system increase pain sensitivity and vice versa. Increased sensitivity of the nervous system to stimuli may actually create the TrPs.

A recent study from the University of Granada in Spain showed that people with higher levels of neck pain were more likely to have trigger points and more of them. The number of days from the accident was a factor. The more time the nervous system is stimulated by the trigger points, the less it takes to set them off. At the same time, decreased neck motion was linked with TrPs. But which came first (the altered neck motion and then the TrPs or the TrPs and then the decreased neck motion) remains unclear. Higher pressure pain sensitivity over the cervical spine (neck) is linked with more trigger points.

These findings support the idea that active TrPs generate pain in people with neck pain from a whiplash injury. The natural conclusion is that treating TrPs may be one way to reduce pain for individuals with whiplash-associated disorder.

Reference: Antonio Manuel Fernández-Pérez, PT, MSc, et al. Muscle Trigger Points, Pressure Pain Threshold, and Cervical Range of Motion in Patients with High Level of Disability Related to Acute Whiplash Injury. In Journal of Orthopaedic & Sports Therapy. July 2012. Vol. 42. No. 7. Pp. 634-641.