What are Trigger Points?
A trigger point is the point along a taut band in a muscle where the most tenderness is felt. This may be described as a knot. The patient will feel the greatest sensitivity in that point & the therapist will feel that area to resist palpation the most. A trigger point is painful on compression & can cause referred pain & issues such as visual disturbances, redness, balance disturbances, reduction in local vascular activity & skin temperature. The degree of irritability of the trigger point defines the degree of pain. The more irritated the trigger point, the greater the degree of pain throughout the referred pain pattern.
How Does a Trigger Point Develop?
A trigger point may begin with a muscle strain or overuse that becomes the site of sensitised nerves, increased cellular metabolism & decreased circulation. They are most likely to develop due to activities or postural stresses (such as the use of a PC).
Types of Trigger Point
Trigger points can be classed as latent or active. Both will cause stiffness & weakness of the muscle & restrict the muscles range of movement. Both types are tender when palpated.
Active trigger points produce pain which tends to be referred away from the affected muscle in a characteristic pain pattern. There may be a sudden onset of pain or dysfunction where a specific incident is noted to be the cause of the problem or it may be gradual with the muscle having been stressed over a period of time. The pain may be described as steady, deep , dull & aching. The intensity of the pain can be variable from low to quite severe & may occur at rest or with movement.
Latent trigger points are much more frequent than active trigger points & are commonly found in patterns of muscular constriction that define a person's "normal" posture. A latent trigger point can become active due to overload or overwork fatigue caused by excessive or repetitive actions or sustained contraction of a muscle. Additionally they can be activated by a muscle remaining in a shortened position for a long period of time.
The greater the degree of conditioning of a muscle, the lower the likelihood of trigger point activation. Trigger points will not be fully reduced without clinical intervention.
Treatment of Trigger Points
Specific palpation techniques are used to identify trigger points within a muscle. Once located the trigger point must be reduced. This is primarily achieved through needling or compression. Compression requires the trigger to be compressed for 15-20 seconds followed by soft tissue manipulation of surrounding muscle tissue to decrease local constrictions & taut muscular bands.
Once the trigger points have been sufficiently reduced, the patient is prescribed stretching exercises specific to the relevant muscles to prevent them from returning to a shortened state. Depending on the degree of weakness of the muscle, as long as the muscle is not returning to a contracted state, the patient is instructed on specific strengthening exercises to prevent the muscle from returning to its previous state.
Finando, D. & Finando, S. (2005). Trigger Point Therapy for Myofascial Pain. Rochester: Healing Arts Press.