Maureen Dwight Registered Physiotherapist, Clinical Musculoskeletal Specialist, Advanced Spinal Practitioner ISAEC
There is a common saying in our industry stating that nerves which fire together wire together. This principle is the basis of motor coordination and reflects our brain’s capacity for plasticity. Brain plasticity causes low back pain by making it harder to relearn how not to be injured. The key premise is that as we develop motor skills our nervous system is learning which muscles work together to produce a movement. The more we practice, the smoother and more automatic the movement becomes until finally it is “grooved” and we no longer have to think about it.
This principle applies to our early childhood, when we learned our basic motor skills of rolling over, sitting and walking. It also applies to the sports we learn. We see it at its best in the finest athletes. Even when they are performing the seeming impossible, they look effortless. Their refined coordination means they exert less energy, take longer to get tired and just plain look better than everyone else when they are working at maximum.
Compensatory Movement Patterns
Brain plasticity also applies to injury. While we are injured many of us use compensatory movement patterns to keep going. These adaptations allow us to stay active while avoiding strain on the damaged tissues. When a muscle is damaged the body innately shifts our movement to engage other muscles, limiting the demand on the weakened structure.
Whether you sprain a ligament or hurt a joint, you will naturally splint the area, stiffening your muscles to avoid further damage. These changes are reflected in our movements. We may limp, lock our knee or even hop on one foot to avoid putting weight on an injured leg. During this period our brain and spinal cord (Central Nervous System) are “learning” these movement patterns. Committed to efficiency the nervous system begins to re-wire these muscles to work together. Initially these adaptations can be useful however when we use compensatory movements too long the wiring becomes established. We over-ride healthier movements, making it harder to go back to our original, more efficient movement patterns.
Even though the injury may be short lived, the effect of compensatory movements can last long after our tissues have healed.
Although compensatory motion can occur with any injury, these changes are more likely to be a problem when we hurt our back or neck. Injuries to ankles or knees may involve the joint, ligament or muscle but when we hurt the spine it will often affect our nerves. Once nerves are involved the nature of the injury changes. Nerves are exquisitely sensitive structures which directly affect pain. Their involvement has a more direct impact on coordination as they are the communication pathway between our muscles, the brain and spinal cord.
Brain plasticity causes low back pain
I find the implications of brain plasticity on low back pain one of the most interesting research areas to emerge in my field. At the forefront are researchers such as Dr. Paul Hodges, Dr. L. Danneels and Dr. Simon Brumagne, whose presentations I had the fortune of sitting in on at the North American Spine Society meeting last fall. Their research uses highly sophisticated equipment, including Transcranial Magnetic stimulation and functional MRI (fMRI), to watch the brain function in real time. One aspect of these studies looks at which areas of the brain are used to coordinate certain movements. This information is then compared to the brain of individuals who have low back pain.
In fMRI the activity in the brain is represented by light. The more areas that light up, the more energy we are using to perform the task. The larger the area that lights up, the “harder” we are working to complete the task. What these studies confirm is that the activity in the brain is changed from back pain. Whereas a non-back pain sufferer may “light up” only a few areas, the low back pain person recruits a much larger area to perform the same motor activity. This finding is consistent with the theory my colleague John Gray wrote about in When Hamstrings Attack :
“low back pain sufferers often use a high load strategy for low load activities”
This theory, along with this impressive quality of research to support it, indicates that after back injuries some movement patterns are less efficient. Too many muscles and/or too much thought process is being utilized to perform a simple task.
This pattern is also consistent with another function studied with fMRI several years ago, . Most of us understand that it is easier to learn a language when we are young. Studies confirm that this is because we are more efficient at coordinating speech. We use a relatively smaller number of areas of the brain to process and produce language. If we add more languages later in life we access a larger number of areas of the brain, increasing the “work” and reducing the efficiency of speaking in another language. This lower level of efficiency is one of the theories proposing why age, brain injury or stroke causes some people to revert to their first language.
The current terminology describing the changes seen in the brain with low back pain is “smudging”. Instead of seeing localized pockets of specific and efficient muscle activity, there is a broader area of involvement. It’s as though someone has taken those points of light and smudged them all together into an indistinct pattern.
The implication of this research for therapy is that it tells us to get better you need to un-smudge these movement patterns. The therapeutic research in this area is just beginning however in the interim this information provides us with important guidance. We now know that in addition to improving strength and more flexibility, most people with chronic or recurrent low back pain need to re-establish muscle coordination (Symptoms of compensation.)
All too often I see clients where their therapy has stopped once they learn how to tighten their abdominal muscles to brace their spine or clench their gluts when they lift. The problem with relying on “remembering” to tighten muscles before you move is that it is slow and takes too much thought process. Movement needs to become easy, automatic and efficient, otherwise the moment you forget to activate these muscles you may get hurt. For our everyday movements we need to strive to be like the athlete, effortless in our walking, sitting, standing etc.
Fortunately brain plasticity and efficiency also work in our favour. The body has been described as being indolently lazy which means we naturally gravitate to movement patterns requiring less energy. Your therapy should take advantage of this innate laziness and focus on re-establishing your more efficient primary “language of movement”. Just as we never forget how to ride a bike, the re-establishment of these pre-injury movement patterns is recognized by your nervous system as requiring lower resources. This propensity helps us to re-establish these basic, more efficient movement choices. Working on a daily program to “remember” how to move non-injured will help to restore your healthier movement patterns, improve your energy, reduce pain and lower your risk for re-injury.
To learn to work less hard and to have less back pain requires an assessment by a therapist who understands the effects and knows where to look for compensatory muscle patterning after injury. The therapists at the Orthopaedic Therapy Clinic are knowledgeable in this retraining. Please contact us to book an assessment if you have chronic or persistent low back pain.
The advice in this article is not meant to replace advice from your health care professional.
 The compensatory relationship of muscles was understood by Leonardo da Vinci in the 1400’s
 Changes in the fMRI have also been seen in scoliosis