Latent myofascial trigger points: their effects on muscle activation and movement efficiency

Effect of Latent Myofascial Trigger Points on Strength Measurements of the Upper Trapezius: A Case-Controlled Trial

“…[2][3][4][5][6][7][8][9] Researchers around the world have investigated various aspects of MTrPs, including their specific etiology, pathophysiology, histology, referred pain patterns, and clinical applications. [3][4][5][6][7][8][9] The existing literature 1,2 has suggested that the presence of MTrPs in a muscle may lead to weakness. Inhibition of muscle activity has been seen in the upper trapezius after experimentally induced pain.…”

“…14 One can infer from this finding that a muscle with an active pain symptom is prone to inhibition, leading to poor contraction capacity and hence to weakness. This concept can be applied in the case of an MTrP as well, but we must note that an active pain symptom is observed only in the presence of an active MTrP, which is compounded by the increased presence of nociceptive substances 6,7 that may cause pain as well as inhibition of nerve conduction at the level of the nerve ending. In the case of a latent MTrP, no active pain symptom is present; moreover, the concentration of nociceptive substances at the site of a latent MTrP is less than that at an active MTrP, 6,7 and thus the contribution of nociceptive inhibition of the nerve endings is also reduced.…”

“…Lucas and colleagues 6 found an alteration in the muscle activation pattern of a muscle group with a latent MTrP, which was corrected after treatment. Shah and colleagues 7 and Shah and Gilliams 8 found elevated levels of sensitizing substances in muscle tissues harbouring MTrPs compared with healthy muscle tissue; sites with active MTrPs had increased levels of sensitizing substances relative to sites with latent MTrPs.…”

“…1 In recent years, a more scientific approach to identifying and understanding MTrPs has developed. [3][4][5][6][7][8][9][10] Despite increasing interest, fundamental understanding of this phenomenon remains based in part on the theories of the early clinicians and still requires experimental verification.…”

“…[6][7][8][9][10] Such altered physiology may affect a muscle's capacity to generate force and, therefore, its strength. Latent MTrPs are clinically significant because they remain clinically quiescent, such that a person will not even be aware of the presence of a trigger point that may render him or her weaker and more susceptible to fatigue.…”