I found a great description of what I call muscular armoring after injury. In this case, Erik Dalton is specifically talking about an injury to the spine:
When the brain senses bony instability or ligamentous damage in-and-around the spine, information is collected so split decisions can be made to determine the extent of threat to the individual and what actions if any need to be taken. Layering the area with protective myospasm is one such decision. It’s the brain’s reflexogenic attempt to prevent further insult to the injured tissues. By ‘splinting’ the area with spasm, the hypercontracted shortened muscles, ligaments and fascia effectively reduce painful joint movements. Splinting is a common form of protective guarding clinicians address day-in and day-out… but how does it develop and how should we treat it?
Let me break this down for you. When pain occurs in the body, the body wants to reduce the pain so that it can heal itself. When the pain is movement-related, that is, across a joint or structure that causes compression or movement of tissue, the body will elicit a temporary spasm of the muscles around the area to keep it still while it heals. This is the “splinting” that he’s referring to. The muscles and soft tissue themselves create areas of muscular spasm to reduce movement of the area while it heals.
Physicians do the same thing with air casts, spints and joint wraps after a injury. They are assisting the body’s need to keep an area immobile while issues in the tissue are healed. The body does the same thing by restricting movement. In this example, the spinal muscles, so important in movement, splint, then require other muscles (normally used for spine and pelvic stabilization) to substitute for them in become active movers in the area. These muscles, unused to this role, tire easily and further contribute to the fatigue and spasm in the area.
Think about it this way. . . What if the doctor never took the cast off? How would your movement and activity be restricted if you kept the cast on after you healed? For many people, injuries cause compensation patterns throughout the body long after the initial injury healed. This is why massage, movement therapies and physical therapy are so important after an injury.