The Effects of Manual Passive Muscle Shortening and Positional Release Therapy on Latent Myofascial Trigger Points of the Upper Trapezius: A Double-Blind Randomized Clinical Trial

Positional release therapy (PRT) has been suggested as an effective treatment for myofascial trigger points (MTrPs). Considering the mechanism of PRT, a new modified technique, known as Manual Passive Muscle Shortening (MPMS), is introduced for the treatment of MTrPs.
To compare the effects of MPMS and PRT on the sensitivity of latent MTrPs in the upper trapezius and determine the active cervical lateral flexion range.
In this double-blind randomized controlled trial, 30 female university students, who were identified with latent MTrPs of the upper trapezius, were recruited from Tabriz University of Medical Sciences, Tabriz, Iran. The participants were randomly allocated into experimental (n, 15) and control (n, 15) groups. The experimental group was treated with the MPMS technique, while the control group received PRT. The participants took part in 3 treatment sessions, as well as a follow-up session 1 week after the third session. During each session, the second physiotherapist, who was blind to the pretreatment information, applied the appropriate technique. The visual analogue scale (VAS), pressure pain threshold (PPT), and bilateral active range of cervical lateral flexion were recorded to assess the effects of treatment. The first physiotherapist, who was blind to the treatment approach for the participants, recorded the outcomes before treatment, during the first session, after treatment (third session), and in the follow-up.
A total of 30 participants were included in the data analysis. In the follow-up, intergroup changes indicated a significant increase in PPT (P = 0.000), a significant decrease in VAS scores (P = 0.002), and a significant increase in the right lateral flexion (P = 0.012) in the experimental group. Left lateral flexion also increased in this group, although it was not statistically significant (P = 0.254). At the end of the study, there were no significant differences between the groups (P > 0.05).
According to the results, both MPMS and PRT were effective techniques in immediate pain relief of upper-trapezius MTrPs. Therefore, MPMS may be used as a new technique in the treatment of MTrPs.