“This significant paper demonstrates that the biochemical milieu of trigger points is acidic and contains a lot of pain-causing metabolites: this is among the best evidence supporting 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 own 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.”