Research & evidence
The integrated hypothesis: why a taut band forms and stays
Excessive acetylcholine release, sustained sarcomere shortening, local ischaemia and sensitising chemistry form a self-perpetuating loop.
Published:
The loop, step by step
The model starts at the motor endplate: excessive acetylcholine release keeps a small cluster of sarcomeres contracted. Sustained contraction compresses local capillaries, so oxygen delivery falls exactly where energy demand is highest.
The resulting energy crisis lowers pH and releases sensitising substances, which in turn increase acetylcholine release. The loop closes on itself, which is why a point can persist for months without any new injury.
Where referred pain fits in
Local chemistry alone does not explain pain felt in a distant area. The expanded model adds central sensitisation: persistent nociceptive input from the muscle lowers the threshold of dorsal horn neurons, which then respond to input from convergent territories, and the brain localises the pain there.
That is why referred zones are reasonably consistent between people, follow neurological convergence rather than dermatomes, and often shrink as the source point calms down.
What the model predicts for treatment
If the loop is the problem, then anything that interrupts it should help: mechanical disruption of the contracted band, restored circulation, reduced sustained load, and less nociceptive drive overall. That is precisely the treatment set with the strongest clinical support today.
It also predicts relapse when perpetuating factors are ignored — the same postural, ergonomic and sleep factors listed on every muscle page here.
Studies cited
Every claim in this article traces back to one of the sources below.
- Gerwin 2004 — An expansion of Simons' integrated hypothesis of trigger point formation. Curr Pain Headache Rep 2004;8(6):468-75 ↗
- Simons 2004 — Review of enigmatic myofascial trigger points as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol 2004;14(1):95-107 ↗
- Shah 2015 — Myofascial trigger points then and now: a historical and scientific perspective. PM R 2015;7(7):746-61 ↗
- Simons & Travell — Myofascial Pain and Dysfunction: The Trigger Point Manual (2nd ed.). Williams & Wilkins, Baltimore ↗
