The effect of thoracic spine high-velocity low-amplitude thrust manipulation on myoelectric activity of the lower trapezius and posterior deltoid muscles during treadmill walking

Abstract

Objectives To investigate the effect of thoracic spine thrust manipulation on the EMG activity of posterior deltoid and lower trapezius during treadmill walking. Methods Volunteers ( n = 40; 19 males and 21 females) were randomly assigned to a ‘sham ultrasound’ control group ( n = 20) or a thoracic spine high-velocity thrust (HVLAT) manipulation group ( n = 20). Surface EMG recordings were collected from the right posterior deltoid and lower trapezius muscles whilst participants walked on a treadmill for 2 min, at 2.8 mph, both prior to and immediately post-intervention. EMG recordings were analysed by evaluating the difference of integral values for pre and post data using repeated measures ANOVA. Results Both control (sham ultrasound) and experimental groups (HVLAT) exhibited small non-significant reductions in post-intervention EMG activity of lower trapezius ( p = 0.201) and a significant reduction in posterior deltoid ( p = 0.003) during treadmill walking. No significant difference was found in the integrated EMG (IEMG) power between control and experimental group in either the ‘before’ or ‘after’ measurements for both target muscles. Conclusions Manipulation of the thoracic spine does not significantly alter the myoelectric activity of lower trapezius and posterior deltoid muscles during treadmill walking.