Clients who indulge in a massage therapy session may experience pinpoints of tenderness or pain in certain areas where the therapist touches, such as in the upper trapezius, lower back or calves. These highly irritable spots within the tissue, called trigger points, are tender or painful when they are touched or compressed. According to the American Family Physician (AFP) website, acute trauma or repetitive microtrauma may lead to stress in the muscle fibers, which cause trigger points to develop. They are “hypersensitive bundle(s) or nodule (s) of muscle fiber” that are hard to the touch when the muscle is palpated. These painful nodules can cause numerous dysfunctions and pain, such as migraine headaches, jaw pain and low back pain. While massage therapy is a common treatment to reduce or eliminate pain caused by trigger points, some physical therapists and massage therapists question whether they really exist in the muscle tissues or in the neural tissues. Should physical and massage therapists address the tissue of the skeletal muscles, tendons, ligaments and fasciae? Or should they focus more on the neural tissue instead?
Trigger points are thought to be located on or within the skeletal muscle fibers, giving a “knotty” sensation when touched or rubbed. Although some medical and massage therapy textbooks often portray trigger points as red dots along the upper back and other body parts like so many oversized pimples, this depiction of trigger points may be oversimplified and misleading. According to Canadian physiotherapist Diane Jacobs, who practices in Weyburn, Saskatchewan, the notion that trigger points are within muscles is based on heuristic thinking. In her blog, HumanAntiGravitySuit, Jacobs stated that the idea of pain from trigger points stems from the association between perceived pain and some body part or a motor unit malfunction.
“I suspect it was the interference with motor output that made it somehow acceptable to leap to the conclusion that muscle was somehow to blame. But it isn’t, not necessarily. Correlation is not causation,” she wrote. “After all, muscle is just doing whatever the CNS [central nervous system] tells it to do. Really. Muscle is just a puppet of the nervous system. It has no ‘behavior’ other than doing whatever the nervous system decides it needs (non-conscious) or wants (conscious) to do.”
Jacobs adds that there is a rich layer of neural structure between the skin and the muscle, including the cutaneous nerves with their rami (nerve branches) extending to just below the skin surface and neural receptors that communicate to the brain about their environment. Smooth muscles are plotted throughout the skin layer and respond reflexively rather than consciously, such as shivering and producing goosebumps. Massage therapy and palpation could stimulate any of these sensory receptors, which may cause pain or tenderness, making trigger points seem to exist in the muscles.
The founders of the trigger point concept were Dr. Janet Travell, M.D., and Dr. David Simons, M.D., who authored a book called Myofascial Pain and Dysfunction: The Trigger Point Manual that was considered the “bible” of trigger point therapy by some massage and physical therapists in the 1990s. The book contained numerous diagrams and illustrations that depicted where trigger points were located on various parts of the body. Dr. Frederick Wolfe, M.D., the director of the National Databank for Rheumatic Diseases, criticized Travell’s and Simons’ work and claimed that it lacked evidence, validation and reliability.
“The book represented opinion, not science,” Wolfe wrote on The Fibromyalgia Perplex blog on February 2013. “There were almost no studies in the Travell-Simons book, just testaments. Most of the perpetuating factors were plain wrong, and represented outdated, overthrown junk science.”
Wolfe, Simons, and three other myofascial pain experts — who were handpicked by Simons — conducted a trigger point study in 1992. Simons and the other three experts blindly examined four patients with myofascial pain. Some of the these patients had fibromyalgia. Simons and the experts took as much time as they needed to find the trigger points. They could only examine, and could not interview the patients. Despite their expertise, no one could agree or find the trigger points. The examiners complained that the study was not fair and wanted to change the study’s protocol and aims, which led to a heated argument between Wolfe’s team and Simons’ team that almost prevented the study’s publication.
“But time took over; people forgot, and the study—a little toned down—came out in the Journal of Rheumatology,” Wolf wrote.
Jacobs mentioned in an online interview that the illustration about trigger point palpation is misleading.”There is a lot of physiologically sensitive tissue between the surface of the skin and muscle,” Jacobs said in an online interview. “It’s like there is no blubber layer present. Or dense fascia. It totally installs pareidolia. In reality the skin organ is thick, even on a thin person. So, there are a lot of possibilities – sore spots [trigger points] could be anything. My guess is they are neural. I wouldn’t rule out vascular though.”
Pareidolia is a psychological phenomenon in which people have a tendency to see or hear a vague or random image or sound as something significant, according to Live Science. It is a form of apophenia, which is a general term for finding patterns in random data. Pareidolia can also be applied to the sense of touch in massage and physical therapy.
“Any sense can be misinterpreted by the brain. Palpation is absolutely rife with illusion,” said Jacobs. “Then we build models out of them, like SI joint palpation. Then we build biomechanical assessments around them. Then we defend them bitterly against all reason. It’s all post hoc reasoning. We can’t get away from that entirely, but we can be aware that we might not have a correlation, and we can try to be less wrong.”
Science writer and registered massage therapist Paul Ingraham stated that trigger points as a painful phenomenon are quite real — no one doubts that, not even the harshest skeptics. “What is in doubt is the explanation, whether they are a tangible thing or just a neurological phantom,” Ingraham said in an online interview. “In no way should this theoretical speculation about the nature of trigger points be discouraging to anyone.” On his website, Save Yourself, Ingraham questions the issues with trigger points. “The purpose of the article is to raise concerns and issues, and to begin addressing the reasonable and fair questions of skeptics about the science of trigger points. It does not come to a conclusion, never mind a condemnation of trigger point therapy as a modality. It is also conspicuously incomplete and inconclusive. The bottom line is that we do not really know how/why people develop the sensation of ‘muscle pain.”
While the exact nature of trigger points is still undetermined, Jacobs recommends that physical and massage therapy professionals should address the nervous system rather than the short-lived “mesodermal derivatives” that have no control of themselves. Treat the nervous system because “it can respond to what you do,” she wrote.
By Nick Ng
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