Trigger points are involuntary tight tender spots in a contracted muscle. This creates pain and dysfunction within the muscle. They are in parts of the muscle where there is decreased circulation, increased muscle contraction, spasm and increased nerve sensitivity causing a sharp pain or a constant ache. They also can cause referred pain, or pain felt in other parts of the body.

Trigger points develop from either stress, repetitive or overuse of a muscle, trauma or accident, structural imbalance, improper stretching or no stretching before physical activity. When a muscle is overused or injured a contraction develops and knots occur. These knots develop when individual muscle fibers are over-stimulated and unable to release their contracted state. This contraction reduces blood flow resulting in a diminished supply of oxygen and a build up of metabolic waste. The contracted muscle (trigger point) reacts by sending out signals of pain.