Immediate effects of thoracic spinal mobilisation on erector spinae muscle activity and pain in patients with thoracic spine pain: a preliminary randomised controlled trial

ObjectivesTo investigate the activity of the thoracic erector spinae muscles and perceived pain intensity immediately after central postero-anterior (PA) mobilisation of the thoracic spine.DesignRandomised, placebo-controlled, experimental design.Participants and interventionsThirty-four participants with non-specific thoracic pain were randomised to the experimental group [grade III central PA mobilisation performed for 3 minutes at the level of the seventh thoracic vertebra (T7)] or the placebo group (less than grade I central PA mobilisation performed for 3 minutes at T7).Main outcome measuresBefore and immediately after PA mobilisation, surface electromyography (EMG) was recorded from the thoracic erector spinae muscles as the participants performed 10° spine extension from a prone position for 10 seconds. Each participant rated their pain intensity as an investigator performed grade III central PA over the most symptomatic thoracic segment, and the pressure pain threshold (PPT) was evaluated bilaterally over the erector spinae muscles.ResultsThe EMG amplitude of thoracic erector spinae activity was reduced significantly after the intervention in the experimental group (P < 0.05), but not in the placebo group. The difference between the groups was significant {pre-post change: placebo −14 [standard deviation (SD) 50] mV, experimental 28 (SD 48) mV; mean difference −42 mV; 95% confidence interval of the difference −76 to 7; P < 0.05} albeit small (Grissom = 0.44). However, both groups showed a significant reduction in pain immediately after the intervention, and both groups showed a similar pre-post change in PPT.ConclusionThese preliminary findings indicate that grade III central mobilisation over the most symptomatic thoracic segment reduces thoracic erector spinae activity during extension of the trunk in people with non-specific thoracic spine pain.Clinical trial registration numberISRCTN47601528.