Scapular Motion: Accuracy and Reliability of Anatomical Marker and Acromion Marker Cluster Methods

INTRODUCTION To assess scapular motion using reflective skin markers, two main methods can be used. The International Society of Biomechanics recommends to place three markers on three anatomical landmarks of the scapula (3AL) [1]. This method suffers from soft tissue artefact error [2]. To reduce it, Van Andel et al., proposes the use of an acromion marker cluster (AMC). It approximates real motion but provides also error measurement [3]. To our knowledge, the evaluation of the recommended method, 3AL, and the new method, AMC, have not yet been realized during the same motion. The aim of this study was to evaluate accuracy and reliability of both methods during shoulder flexion. Palpation was carried out to obtain real scapular motion, considering this method as a gold standard for static measurement of scapula kinematics [4].