A systematic review of 3D scapular kinematics and muscle activity during elevation in stroke subjects and controls

Through the onset of post-stroke motor disorders, the normal scapular function is compromised. As a result, shoulder pain and associated upper limb dysfunctions frequently arise after stroke. This review aimed to provide a systematic overview of available literature on scapular function, i.e. scapular three-dimensional (3D) kinematics and muscle activity during elevation, in healthy persons, persons with primary shoulder disorders and post-stroke patients. 3D scapular kinematics have been widely reported in healthy persons and persons with primary shoulder disorders, whereby a general pattern of upward rotation and posterior tilt during elevation has been agreed upon. Results on scapular internal/external rotation are inconsistent. In a post-stroke population, 3D scapular kinematics are less frequently reported. Scapular muscle activity has thus far been studied to very limited extend and firm conclusions could not be drawn. Although 3D scapular kinematics and muscle activity registrations are being increasingly used, some general methodological aspects should be considered. While the International Society of Biomechanics already proposed recommendations on the definition of upper limb joint coordinate systems and rotation sequences, proper result comparison necessitates further guidelines on other methodological aspects, i.e. data collection, processing, analyzing, and reporting.