In managing Myofascial Pain Syndromes, the elicitation of muscle twitches is still considered as the hallmark of effective treatment. These local twitches/contractions seem to result from:
- Stimulation of the motor end-plate zones (MEPZs) which elicits large muscle twitches (Needle Induced Contractions)
- The insertional activity causes depolarization of innervated single or grouped muscle fibers resulting in micro twitches.
When a needle is inserted into muscle anywhere between three and fifteen thousand individual muscle fibers can be cut. Thus, twitch responses seize during the needling process, as the gated flow of calcium is interrupted both through the axon terminal and sarcolemma.
Chu J. Zhonghua Yi Xue Za Zhi (Taipei). The local mechanism of acupuncture. 2002 Jul;65(7):299-302.