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The Pain & Therapy Bibliography, Record ID 6265 {show all records}

Biochemicals associated with pain and inflammation are elevated in sites near to and remote from active myofascial trigger points

added May 12, 08, updated Jan 25, 15


This important paper demonstrates that the biochemical milieu of trigger points is acidic and contains a lot of pain-causing metabolites: good evidence in support of the energy crisis theory of trigger point formation and/or perpetuation. It’s an improvement on an earlier paper from 2005 (Shah), with improved methods. It is cogently summarized by Simons, and in my short article Toxic Muscle Knots.

The validity of these findings have been questioned by Quintner et al. I think their concerns are justified, but it is a legitimate and unfinished scientific controversy.

item type
article in a journal
Jay P Shah, Jerome V Danoff, Mehul J Desai, Sagar Parikh, Lynn Y Nakamura, Terry M Phillips, and Lynn H Gerber
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Archives of Physical Medicine & Rehabilitation


OBJECTIVES: To investigate the biochemical milieu of the upper trapezius muscle in subjects with active, latent, or absent myofascial trigger points (MTPs) and to contrast this with that of the noninvolved gastrocnemius muscle.

DESIGN: We used a microanalytic technique, including needle insertions at standardized locations in subjects identified as active (having neck pain and MTP), latent (no neck pain but with MTP), or normal (no neck pain, no MTP). We followed a predetermined sampling schedule; first in the trapezius muscle and then in normal gastrocnemius muscle, to measure pH, bradykinin, substance P, calcitonin gene-related peptide, tumor necrosis factor alpha, interleukin 1beta (IL-1beta), IL-6, IL-8, serotonin, and norepinephrine, using immunocapillary electrophoresis and capillary electrochromatography. Pressure algometry was obtained. We compared analyte concentrations among groups with 2-way repeated-measures analysis of variance.

SETTING: A biomedical research facility.

PARTICIPANTS: Nine healthy volunteer subjects.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Preselected analyte concentrations.

RESULTS: Within the trapezius muscle, concentrations for all analytes were higher in active subjects than in latent or normal subjects (P<.002); pH was lower (P<.03). At needle insertion, analyte concentrations in the trapezius for the active group were always higher (pH not different) than concentrations in the gastrocnemius muscle. At all times within the gastrocnemius, the active group had higher concentrations of all analytes than did subjects in the latent and normal groups (P<.05); pH was lower (P<.01).

CONCLUSIONS: We have shown the feasibility of continuous, in vivo recovery of small molecules from soft tissue without harmful effects. Subjects with active MTPs in the trapezius muscle have a biochemical milieu of selected inflammatory mediators, neuropeptides, cytokines, and catecholamines different from subjects with latent or absent MTPs in their trapezius. These concentrations also differ quantitatively from a remote, uninvolved site in the gastrocnemius muscle. The milieu of the gastrocnemius in subjects with active MTPs in the trapezius differs from subjects without active MTPs.

related content

  1. “An in vivo microanalytical technique for measuring the local biochemical milieu of human skeletal muscle,” an article in Journal of Applied Physiology, 2005.
  2. “New Views of Myofascial Trigger Points: Etiology and Diagnosis,” an article in Archives of Physical Medicine & Rehabilitation, 2008.
  3. PS Toxic Muscle Knots — Research suggests myofascial trigger points may be quagmires of irritating molecules

These seven articles on PainScience.com cite this paper as a source:

  1. Trigger Points & Myofascial Pain Syndrome
  2. Save Yourself from Plantar Fasciitis!
  3. Save Yourself from Shin Splints!
  4. Dance of the Sarcomeres
  5. Toxic Muscle Knots
  6. Into the Fire
  7. Should You Drink Water After Massage?