With this in mind, research has found that starting a shoulder shrug in 30 of glenohumeral abduction (i.e., arms slightly out to the sides), which is a component of slight
scapula upward rotation, generated greater upper trapezius muscle activity in comparison with the shrug with the arms at the side (1).
The
scapula should be able to go through
upward rotation, downward
rotation, protraction, retraction, abduction, and posterior tilting.