Immediate effects of cervical mobilisations on neck muscle activity during active neck movements in patients with non-specific neck pain. A double blind placebo controlled trial.

Background: Cervical mobilisations are used to treat people with neck pain but their mechanisms of action are unclear. One theorised reason for induced analgesia is effect on neck muscle activity.
Objectives: To assess the effects of cervical mobilisations on muscle activity during active neck movements and whether changes in muscle activity are associated with changes in symptoms.
Design: Double-blind randomised placebo controlled trial.
Setting: Primary care.
Participants: 40 patients (aged 19 to 80 years, 24 female) with non-specific neck pain.
Interventions: One session of cervical mobilisations or motionless manual contact (placebo).
Main Outcome Measures: sternocleidomastoid (SCM), scalene (SCA), upper trapezius (UT) and erector spinae (ES) surface electromyography (SEMG) during active neck flexion, extension, side flexion and rotation was measured immediately before and after the intervention. Patients were classified as responders according to change in symptoms assessed using the Global Rating of Change Scale (GROC).
Results: Compared with placebo, patients receiving mobilisation showed an increase in contralateral UT and ES SEMG during rotation and contralateral and ipsilateral SCM, SCA and UT during side flexion (P<0.05), however changes were mostly associated with an increase in range and speed of movement. The only association with GROC was increased (5%) SEMG in the contralateral SCM during side flexion in the mobilisation group (P=0.013).
Conclusion: Cervical mobilisations caused increased neck SEMG, mostly due to increased movement range and speed. Change in muscle activity is unlikely to be a major mechanism of action of cervical mobilisations in symptomatic improvement with physiological neck movements. (ClinicalTrials.gov record number: 2016/066).
Clinical Trials Registry: ClinicalTrials.gov record number: 2016/066.
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