Short- and medium-term effects of manual therapy on cervical active range of motion and pressure pain sensitivity in latent myofascial pain of the upper trapezius muscle: a randomized controlled trial.

OBJECTIVE: The purpose of this study was to investigate effects of different manual techniques on cervical ranges of motion and pressure pain sensitivity in subjects with latent trigger point of the upper trapezius muscle. METHODS: One hundred seventeen volunteers, with a unilateral latent trigger point on upper trapezius due to computer work, were randomly divided into 5 groups: ischemic compression (IC) group (n=24); passive stretching group (n=23); muscle energy technique group (n=23); and 2 control groups, wait-and-see group (n=25) and placebo group (n=22). Cervical spine range of movement was measured using a cervical range of motion instrument as well as pressure pain sensitivity by means of an algometer and a visual analog scale. Outcomes were assessed pretreatment, immediately, and 24 hours after the intervention and 1 week later by a blind researcher. A 4×5 mixed repeated-measures analysis of variance was used to examine the effects of the intervention and Cohen d coefficient was used. RESULTS: A group-by-time interaction was detected in all variables (P<.01), except contralateral rotation. The immediate effect sizes of the contralateral flexion, ipsilateral rotation, and pressure pain threshold were large for 3 experimental groups. Nevertheless, after 24 hours and 1 week, only IC group maintained the effect size. CONCLUSIONS: Manual techniques on upper trapezius with latent trigger point seemed to improve the cervical range of motion and the pressure pain sensitivity. These effects persist after 1 week in the IC group.

The immediate effects of atlanto-occipital joint manipulation and suboccipital muscle inhibition technique on active mouth opening and pressure pain sensitivity over latent myofascial trigger points in the masticatory muscles.

DESIGN: A randomized controlled trial. OBJECTIVE: To investigate the immediate effects on pressure pain thresholds over latent trigger points (TrPs) in the masseter and temporalis muscles and active mouth opening following atlanto-occipital joint thrust manipulation or a soft tissue manual intervention targeted to the suboccipital muscles. BACKGROUND: Previous studies have described hypoalgesic effects of neck manipulative interventions over TrPs in the cervical musculature. There is a lack of studies analyzing these mechanisms over TrPs of muscles innervated by the trigeminal nerve. METHODS: One hundred twenty-two volunteers, 31 men and 91 women, between the ages of 18 and 30 years, with latent TrPs in the masseter muscle, were randomly divided into 3 groups: a manipulative group who received an atlanto-occipital joint thrust, a soft tissue group who received an inhibition technique over the suboccipital muscles, and a control group who did not receive an intervention. Pressure pain thresholds over latent TrPs in the masseter and temporalis muscles, and active mouth opening were assessed pretreatment and 2 minutes posttreatment by a blinded assessor. Mixed-model analyses of variance (ANOVA) were used to examine the effects of interventions on each outcome, with group as the between-subjects variable and time as the within-subjects variable. The primary analysis was the group-by-time interaction. RESULTS: The 2-by-3 mixed-model ANOVA revealed a significant group-by-time interaction for changes in pressure pain thresholds over masseter (P<.01) and temporalis (P = .003) muscle latent TrPs and also for active mouth opening (P<.001) in favor of the manipulative and soft tissue groups. Between-group effect sizes were small. CONCLUSIONS: The application of an atlanto-occipital thrust manipulation or soft tissue technique targeted to the suboccipital muscles led to an immediate increase in pressure pain thresholds over latent TrPs in the masseter and temporalis muscles and an increase in maximum active mouth opening. Nevertheless, the effects of both interventions were small and future studies are required to elucidate the clinical relevance of these changes. LEVEL OF EVIDENCE: Therapy, level 1b.J Orthop Sports Phys Ther 2010;40(5):310-317, Epub 12 April 2010. doi:10.2519/jospt.2010.3257.