Clients often come to me with a “knot” in their back or their necks. And occasionally, one of them will ask me the question I’ve just posed above: “Exactly what is a knot?” I swear that they’re picturing a nice little half hitch or slipknot in their muscle fibers. But a knot, in this context, is less like something you learn in Boy Scouts, with loops and twists, and more like what you find in a piece of wood: a hard place.
In reality, a knot in the muscle occurs when a section of the muscle becomes constricted (or compressed). The scientific term for this state is a myofascial trigger point, with myo meaning muscle and fascial referring to the connective tissue surrounding the muscle. Knots can form when some event generates a reaction in which the muscle never relaxes, which leads to a muscle spasm. The spasm creates a sense of chronic tightness—a.k.a. “a knot.” The word spasm might seem to suggest a sudden series of muscle contractions and relaxations—a jumpiness in the muscle—but a spasm can also be a single prolonged involuntary muscle contraction, or abnormal tightness.
Muscle constriction can also occur as a result of small amounts of scar tissue developing through an injury or even just repetitive motion, from microscopic damage to muscle fibers. Scar tissue is an inflexible collagen fibrous material that, once created, can adhere to muscle fibers, preventing them from sliding back and forth over one another as they should, as well as to connective tissue, reducing muscle flexibility. Muscle fibers can also adhere to one another as a result of, for example, dehydration.
One of the reasons that massage is so effective at treating knots is that it helps loosen such adhesions, allowing the muscle fibers to slide over each other again, and it also helps reintegrate the scar tissue into the muscle, reducing its inelasticity and thereby restoring the muscle to a more flexible state.