Pain and movement have a very intimate relationship, with each capable of affecting the other. Pain from whatever source, be it from an acute injury or a progressive disease process, will cause someone to move very differently to try and protect the painful area. But, incorrect postures and movement patterns can also cause pain by overloading joints and muscles.
As you can see, in one case poor movement causes pain and in the other pain causes altered movement.
Pain will normally subside on its own and movement often returns to normal. However, sometimes the way movement is controlled and the way muscles work can remain affected even after healing has occurred or when the pain has gone. This can be because of a deliberate conscious decision on behalf of the pain sufferer or because of changes in the subconscious way movement is controlled in the spinal cord or the brain.
You can describe a person’s reaction to pain in terms of adaptive and maladaptive behaviour. For example, someone who has acute ankle sprain and suffers pain will limp for a while, reduce their activity or even take to using crutches. This allows the injured part to recover and early healing to take place. This is adaptive, ie they adapt their behaviour to suit the condition. As the ankle improves they will start to move it and gradually increase their activity levels again. This helps the tissue to heal effectively.
Someone who rests the ankle for too long, usually out of fear of pain or fear of making the problem worse, is displaying maladaptive behaviour. They are depriving the healing tissues of the mechanical stimulus it requires to heal effectively by not moving properly.
This response is quite common and can be seen in different parts of the body, very commonly with people with spinal pain.
Not only will this inhibit the healing process but it will lead to joint stiffness, muscle weakness and reduced co-ordination making the whole problem much worse than it need be. It will therefore maintain and reinforce incorrect movement of that joint.
Pain also has a direct reflex effect on movement in the Central Nervous System, that is the spinal cord and the brain itself. You will probably be familiar with pain causing muscle spasm. This happens to the big, strong, superficial muscles which are used to produce movement. But pain also has an inhibitory effect on deeper muscles which are more concerned with control, stability and co- ordination of joints. So an imbalance occurs whereby superficial muscles work harder and the deeper muscles work less. As superficial muscles are made to work more they fatigue causing more pain and perpetuating the process.
Over time this altered pattern of muscle activity is remembered and learnt by the parts of the brain concerned with movement. This leads to ongoing altered movement.
In both cases the altered movement can impair normal healing and even cause other problems in other areas as they are forced to compensate.
In physiotherapy, we aim to re- train the role of these different muscles and normal patterns of movement. This then allows any structures that being over strained to settle and heal. This also helps reduce the risk of recurrent episodes of pain.