The importance of the SA is further evidenced by the
presence of abnormal muscle activation in various shoulder
pathologies.6,15,22,27 Reduced SA electromyographic
(EMG) activity has been demonstrated in throwers with
glenohumeral instability,6 construction workers with
shoulder impingement,15 and swimmers with shoulder
pain.27 This reduction in muscle activity has been related
to abnormal scapular motion.15 Therefore, the SA is
.