How it works – The basics of physiology
Muscle origin and insertion
All muscles have a starting point on a bone (origin) and an ending point on a bone (insertion). Muscles are attached to the bone by a tendon. Think of a chicken drumstick. When you pull the meat away from the bone, it is adhered at the end by a clear or whitish tough cord. This is the tendon. A therapist can move a muscle into a lengthened position (stretch) or shortened position by knowing the origin and insertion of that particular muscle. By moving the bones, muscles can be put into a fully lengthened position, a shortened position or anywhere in between.
Sensory Input and Motor Output
All muscles communicate to the spinal cord and brain (central nervous system) via sensory nerves and receptors located in the tendon. These receptors called golgi tendon organs and muscle spindle fibers, relay information about the length of the muscles and how fast and in what direction the muscle is moving the bones and joints. They also communicate what state of contraction the muscle is in at rest (muscle tone). This is a part of our sensory feedback system which the nervous system uses to decide how to instruct the muscle what to do next (motor output). Our sensory system is highly sophisticated and sensitive. It provides our nervous system with the information to make rapid decisions to plot a course of action based on the desired activity of the brain while also avoiding injury.
Muscle Tone
Our central nervous system supplies a certain amount of constant output to each of our muscles. This is called the muscles’ tone. Without any input the muscle is flaccid (abnormal state) as seen in a stroke. With too much output a muscle is spastic and can make lengthening movement of a muscle nearly impossible. In between flaccid and spastic is a resting state for normal that varies with the individual.
Muscle tone continuum
l_______l______l_______l_________l______l________l________l
FLACCID RELAXED NORMAL TENSE SPASM SPASTIC
(ABNORMAL) (ABNORMAL)
Muscle spasm – A vicious cycle.
A protective mechanism of the body based on these principles is called a muscle spasm. When the body perceives danger to a joint, the nervous system instructs the muscle to contract strongly to prevent movement that may cause damage. The muscle can stay in this state for a few minutes or a few days. It can become chronic and then this mechanism rarely serves to help or protect the body any longer and can become detrimental.
A vicious cycle is developed with pain, muscle guarding and muscle spasm.
A muscle in spasm is constantly sending signals to the nervous system, much like listening to music that is too loud. The nervous system reacts by sending strong signals right back. This is how a muscle can get into a vicious circle with the nervous system.
How it works – the technique
- The therapist identifies the muscle in spasm.
- The muscle can be in visible or palpable spasm or can be identified by “tender points”. The therapist positions the body so the muscle is in a shortened position and holds the position for at least 90 seconds. At times, the position is held greater that 5 minutes waiting for changes in muscle and fascia (tissues surrounding muscles and organs. More about this will be explained in future articles.)
- The therapist monitors tissue change and waits for optimum improvement to occur.
The shortened position of a muscle is a non-threatening position for a muscle in spasm. The communication from the muscle to the nervous system at this time is one of relaxation. The nervous system no longer receives the excessive feedback from the muscle and instructs the muscle tone to change from spasm to a resting tone. Relief and restoration of motion is often immediate. By disarming muscle spasm in major muscle groups the body is able to return to pain free function and pain free movement can be restored and built upon with exercise.
This technique lays the groundwork for rehabilitation of any painful condition. This technique is best used for:
- Spasm in any area of the body
- Post surgery in any area of the body
- Restoring more upright posture (tightened muscles can pull you into poor posture)
- Chronic pain
Can a muscle be in spasm (hypertonic) without a person knowing it?
Yes! People experience decreased mobility, tightness, or nothing at all if another muscle is compensating for it.
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