Shoulder pain is a common and debilitating condi tion, and its prevalence is second only to low back pain. 9,42,52,63 Shoulder im pingement syndrome (SIS) is the most frequently encountered shoulder condition and accounts for 44% to 65% of all shoulder pain. 63 A greater amount of scapular internal rotation, as well as a lesser amount of scapular upward rotation and posterior tilt during arm elevation, has previously been documented in individuals with symptoms of SIS compared to asymptomatic individuals. [35][36][37][38] These kinematic alterations have been associated with lesser activation of the middle and lower trapezius and serratus anterior muscles and excessive upper trapezius muscle activation. 37,51 Systematic literature reviews support the efficacy of therapeutic exercises for the rehabilitation of individuals with SIS, 29,43 and the results of randomized clinical trials suggest that providing manual therapy T T OBJECTIVES:To evaluate the immediate effects of a low-amplitude, high-velocity thrust thoracic spine manipulation (TSM) on pain and scapular kinematics during elevation and lowering of the arm in individuals with shoulder impingement syndrome (SIS). The secondary objective was to evaluate the immediate effects of TSM on scapular kinematics during elevation and lowering of the arm in individuals without symptoms. T T BACKGROUND:Considering the regional interdependence among the shoulder and the thoracic and cervical spines, TSM may improve pain and function in individuals with SIS. Comparing individuals with SIS to those without shoulder pathology may provide information on the effects of TSM specifically in those with SIS. T T METHODS:Fifty subjects (mean  SD age, 31.8  10.9 years) with SIS and 47 subjects (age, 25.8  5.0 years) asymptomatic for shoulder dysfunction were randomly assigned to 1 of 2 interventions: TSM or a sham intervention. Scapular kinematics were analyzed during elevation and lowering of the arm in the sagittal plane, and a numeric pain rating scale was used to assess shoulder pain during arm movement at preintervention and postintervention.