The theory behind neuromuscular massage is that when a muscle spasms – due to one of any number of stimuli – it is not caused by a spasm in the entire muscle, but by a spasm in a very centralized area of the muscle, which may then reverberate to other areas of the muscle, causing pain.
This small area is called a trigger point because it is the area that “triggers” pain in another area of the muscle, sometimes called referring or transferring.
When a muscle (or trigger point) spasms in the body, blood flow to that area is severely decreased, sometimes ceasing altogether. When the blood flow is diminished, oxygen necessary for the muscle to work properly is also decreased, causing a buildup of lactic acid. This causes a sensation similar to the one felt after a long workout – muscle soreness.
The problem is that this can turn into a vicious cycle of soreness and pain because the buildup of lactic acid combined with the body’s desire to compensate for the pain will inevitably lead to less blood flow, less oxygen, and the continued production of lactic acid. This is why muscle soreness and pain can continue for years unabated.