HOW DO HEALTHY MUSCLES NORMALLY ACT AND HOW DO THEY BECOME SOURCES OF CHRONIC PAIN?

This blog will introduce you to several basic concepts of how muscles function normally and what happens to them when they become involved in chronic pain. Before you can take any effective remedial actions to restore muscles involved in chronic pain to their normal healthy state, it is critical to understand exactly how muscles act under normal healthy circumstances. 

All muscles attached to our bones and joints are called skeletal muscles. They act to move body parts by shortening, i.e., by contracting, followed by lengthening, i.e., relaxing. The distance between a muscle’s fully contracted location and its fully relaxed location is called its range of motion. When a muscle’s normal sequence of smoothly contracting and fully relaxing is disrupted, it  loses part of its range of motion, develops focal sites of sustained contraction inside itself which makes it susceptible to injury.

If this situation is not remedied, by eliminating the sites of contraction inside the muscle and restoring its normal range of motion, the nerves  inside the muscle and the nerve cells they connect with inside the spinal cord and brain can become damaged. If this happens, then  our normal pain pathway circuits become permanently altered. It is through this sequence of events that a muscle can become a source of chronic pain.

Skeletal muscles for the most part fall into one of two categories, flexors and extensors. It is critical to understand the differences between them before being able to take effective remedial actions.

When flexors contract, they move the bones of a joint in such a way as to decrease the angle of the joint they act on. When extensors contract, they do the opposite, i.e., they move the bones of a joint to increase the angle of the joint. Many of the most powerful muscles of the body are flexors, for example, the biceps in the arm, the abs in the trunk, the hamstrings in the thigh, the closers of the jaw and the pectorals in the chest. If a flexor does not fully relax and remains in a somewhat contracted state it will not function properly and it will also adversely affect the extensor that works in opposition to it. In such a situation, the extensor will be under excessive tension because it will be unable to fully relax. This sets up a situation where, if it persists for a long enough time, the extensor will only be able to move through part of its range of motion and it will ultimately become chronically painful. In so many chronic pain situations, extensors held under tension become victims of shortened flexors who are the culprits. 

Low back pain is an example of this situation. What typically happens in low back pain is that the abs become shortened and put the low back extensors, which run along the back of the spine, under excessive tension. If this situation is not corrected, the back extensors will begin to hurt and very soon become chronically painful.  This example illustrates what is so frustrating and downright infuriating about chronic pain. No matter what you might do to the back extensors to get relief like, for example, applying heat or cold, massaging them, taking anti-inflammatory medications, the best that you can hope for will only be temporary relief. The pain will inevitably recur until the tension in the lower back extensors (the victims) is relieved. Fortunately, there is a way out of this situation as well as other chronic pain situations. They are described in detail in my Book  (A Way Out Of Chronic Pain) and will be addressed in future Blogs.

The final point of this blog is get you to appreciate that all of the skeletal muscles of the body, and there are over six hundred of them, are in a two way, continuous communication with the brain. Information flows into the brain over sensory nerves and back out to muscles over motor nerves. It is the brain, acting through this two way communication, that sets the tension level in each muscle. The only way to permanently change the tension level in a muscle is to get the brain to reset it. It takes great effort and many repetitions of movements to make such changes happen. This is the reason that chronic pain is so frustrating and difficult to address because it does not lend itself to one step solutions. In future Blogs we will consider  how to get the brain to reset the tension level inside of muscles and increase their range of motion.