Effects of thoracic spinal manipulation on scapular kinematics, pain and scapulothoracic muscles in asymptomatic and shoulder impingement syndrome subjects - randomized controlled trial

Abstract

Subacromial impingement syndrome (SIS) is one of the most common causes of shoulder pain and is related to abnormal kinematics and muscular activation patterns. Considering that there is a regional interdependence among shoulder, thoracic and cervical spine, the thoracic spine manipulation may be effective to treat subjects with SIS as it seems to improve pain and function in subjects with pain and dysfunction. However, there is lack of information about the effects of thoracic manipulation on scapulothoracic kinematics and muscular activation. The main objective of this study will be to evaluate the immediate and short-term effects of a low-amplitude and high-velocity thoracic spine manipulation on scapular kinematics and muscular activation during shoulder elevation in asymptomatic and SIS subjects. Fifty subjects, both genders, with SIS and 50 subjects, both genders, asymptomatic for shoulder dysfunction will participate in this study. All subjects will be randomly assigned to one of the groups: manipulation group or sham group. The manipulation group will receive a thoracic spine manipulation in middle thoracic spine and the sham group will be positioned similarly to the thoracic manipulation group, but the manipulation (high velocity, low amplitude) will not be performed. All subjects will be evaluated in 3 days with 3 to 4 days of interval between each evaluation. Scapular kinematic and muscle activation of upper, middle and lower trapezius and serratus anterior will be analyzed during shoulder elevation in the sagittal plane. The DASH and WORC questionnaires and Numeric Pain Rating Scale will be used to assess shoulder pain and function. Only the affected side will be evaluated in the subjects with SIS. The side to be evaluated will be randomly chosen in the asymptomatic subjects. The statistical analysis will depend on the normality of the data which will be assessed by the Kolmogorov-Smirnov test, with significance set at 5%.