What’s a muscle “knot” and why does it hurt?!

What people often refer to as muscle knots are technically known as muscle trigger points (TrPs). To answer the question of what is actually going on in our body, we must first understand the basic physiology and how this fascinating system works. So, in simple terms, the muscles in our body are a part of a vital organ system called the musculoskeletal system. There are three broad classifications of muscle:

  1. Cardiac
  2. Skeletal
  3. Smooth

The smooth and cardiac muscles are found in your alimentary canal, otherwise known as the gut, and the cardiac muscles are in the heart. These cardiac and smooth muscles are autonomic means we cannot control them at will. The skeletal muscles are the muscles that we use for movement and locomotion; these include every muscle in your body that is under your control, fascinating, right?

Now that we have dotted down some basics let's understand how muscles function and what mechanisms are involved. A muscle is a band; it's a tight, thick cord with smaller fibers entwined. Each muscle fiber is yet another smaller bundle with even smaller microfibrils. This muscle structure follows a concept known as the walk along with theory which explains how every muscle contracts and functions.

Muscle trigger point

A muscle trigger point is a sensitive area in the muscle bundle that causes pain. It is taut and excruciating upon stimulus, and it may also cause pain in the entire muscle of that region. It mainly happens due to the muscle being overused or some traumatic injury. It can happen when you don't do proper warm-ups before lifting heavy weights at the gym. The trigger points are painful sensations and feel like lumps underneath the skin; if they persist, they are classified as a disease called myofascial pain syndrome. A muscle trigger point has several important (3) “clinical feature characteristics of MTrPs: increased muscle tension, pain and tenderness, painful stretch range of motion, initiating causes of MTrPs.”

A muscle trigger point is a taut and sensitive area that your doctor can find when pressing different parts of your muscle. When pressed, a pain stimulus is felt upon which the said area is said to have a trigger point. So in definition a muscle trigger point can be described as (2) “Trigger points are discrete, focal, hyperirritable spots located in a taut band of skeletal muscle. They produce pain locally and in a referred pattern and often accompany chronic musculoskeletal disorders.” Four types of muscle trigger points can be found throughout your body:

  1. Active trigger points: these are tender and taut points present within the muscle bundle, and they cause pain in the entire muscle.
  2. Latent trigger points: Unlike the active trigger points, they do not cause pain upon touching, and they remain dormant and are only activated in case of stress or trauma.
  3. Secondary trigger points: These trigger points cause pain when some other muscle is under pressure or being touched.
  4. Satellite myofascial point: This muscle trigger point gets activated because it is near another muscle trigger point.

Why does a muscle knot cause pain?

A muscle knot or, in other words, a trigger point is a nexus wherein the muscles have tensed up. They are in a state of spasm and are in a constant state of contraction; this causes the bridges between the muscle fibers to utilize ATP constantly, thus creating lactic acid at that particular focal point. The accumulation of lactic acid then causes pain at that point of the muscle. The pain is also partly because the muscle bridges have interlocked themselves and cannot freely return to a state of relaxation. So basically (1) “An individual contraction knot appears as a segment of a muscle fiber with extremely contracted sarcomeres and an increased diameter.”

In upcoming blogs we’ll cover how treatments and how trigger points can be avoided.

  1. Bron, C., & Dommerholt, J. D. (2012, July 27). Etiology of myofascial trigger points - current pain and headache reports. SpringerLink. Retrieved March 22, 2022, from https://link.springer.com/article/10.1007/s11916-012-0289-4
  2. Alvarez, D. J., & Rockwell, P. G. (2002, February 15). Trigger points: Diagnosis and management. American Family Physician. Retrieved March 22, 2022, from https://www.aafp.org/afp/2002/0215/p653.html?userguid=unk-1632566170543&condition=other&clientId=&entityId=203&clientSiteId=default&groupId=&tp=WEB_PORTAL
  3. Simons, D. G. (n.d.). Understanding effective treatments of myofascial trigger points. Define_me. Retrieved March 22, 2022, from https://www.bodyworkmovementtherapies.com/article/S1360-8592(02)90271-8/fulltext
  4. Han, S. C., & Harrison, P. (2007, March 14). Myofascial pain syndrome and trigger-point management. Regional Anesthesia and Pain Medicine. Retrieved March 22, 2022, from https://www.sciencedirect.com/science/article/abs/pii/S1098733906800623
  5. Fricton, J. R., Kroening, R., Haley, D., & Siegert, R. (2005, May 15). Myofascial pain syndrome of the head and neck: A review of clinical characteristics of 164 patients. Oral Surgery, Oral Medicine, Oral Pathology. Retrieved March 22, 2022, from https://www.sciencedirect.com/science/article/abs/pii/0030422085903640
  6. Sikdar, S., Shah, J. P., Gebreab, T., Yen, R.-H., Gilliams, E., Danoff, J., & Gerber, L. H. (2009, November 1). Novel applications of ultrasound technology to visualize and characterize myofascial trigger points and surrounding soft tissue. Archives of Physical Medicine and Rehabilitation. Retrieved March 22, 2022, from https://pubmed.ncbi.nlm.nih.gov/19887205/
  7. Gerwin, R. D. (n.d.). A Review of Myofascial Pain and Fibromyalgia – Factors that Promote Their Persistence. Sage Journals. Retrieved March 22, 2022, from https://journals.sagepub.com/doi/10.1136/aim.23.3.121