When functioning normally, a muscle has optimum circulation and innervation , is able to move freely , is unimpaired in contracting and relaxing , and has normal elasticity and strength . All movements should be free of pain. The muscles are among the most susceptible of body structures. They must continually readjust to their use, disuse, or misuse.
Muscle shortening frequently results.
Stiff or shortened muscles are often activated in movements in which they otherwise would not take part. In general, the shorter the muscle, the more it can inhibit its antagonists. Therefore, stimulating and strengthening a muscle s antagonist always aids treatment. However, note that the shortened muscle being treated should always be stretched before its antagonist are strengthened. Shorthened muscles may cause pain from the periosteum, tendons, or muscle belly, including referred pain to other structures or segmentes.