The effect of manual pressure release on myofascial trigger points in the upper trapezius muscle

Sustained manual pressure has been advocated as effective treatment for myofascial trigger points (MTrPs). This study aimed to investigate the effect of manual pressure release (MPR) on the pressure sensitivity of latent MTrPs in the upper trapezius muscle using a novel pressure algometer. Subjects (N=37, mean age 23.1±3.2, M=12, F=23) were screened for the presence of latent MTrPs in the upper trapezius muscle (tender band that produced referred pain to the neck and/or head on manual pressure). Subjects were randomly allocated into either treatment (MPR) or control (sham myofascial release) groups. The pressure pain threshold (PPT) was recorded pre- and post-intervention using a digital algometer, consisting of a capacitance sensor attached to the tip of the palpating thumb. There was a significant increase in the mean PPT of MTrPs in the upper trapezius following MPR (P<0.001), but not following the sham treatment. Pressure was monitored and maintained during the application of MPR, and a reduction in perceived pain and significant increase in tolerance to treatment pressure (P<0.001) appeared to be caused by a change in tissue sensitivity, rather than an unintentional reduction of pressure by the examiner. The results suggest that MPR may be an effective therapy for MTrPs in the upper trapezius.