For instance, if you bend your finger back as far as you can you will feel pain in the bent joint. This pain stops when you release your finger. This is an example of mechanically produced pain and shows that such mechanical pains can be produced or stopped by body movements and positions. Another mechanism of producing pain is chemical. Chemical pains occurs with the inflammation that follows a sprain or in such diseases as rheumatoid arthritis.
Chemical pain tends to respond well to medications and is generally worsened with movements.
The opposite is true for mechanical pains which respond poorly to pain killers but which respond well to movements. This confirms that in many cases such pains are mechanical in nature and not chemical. The McKenzie Method of physical therapy is a highly effective, mechanical treatment of pain and other symptoms arising from the back or neck. The McKenzie Method analyses the response of the patient's symptoms to mechanical movements of the body. Once the correct movements which centralize the patients pain have been identified by the physical therapist, the patient is taught the simple exercises to address the pain as well as correct postures which will help prevent the problem from recurring.