Muscles which attach to the scapulae that adduct and extend the arm include the posterior deltoid muscles, the teres major, and minor stabilizing contribution from some rotator cuff muscles ( infraspinatus and teres minor as lateral rotators, subscapularis as medial rotators ).
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At the same time, as the arms are brought up with the elbows extended in front of the chest so the bar may now lie across or " rest " across the palms, the front of the shoulder or deltoid muscles, and the clavicles.
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"I see a lot more injuries to the deltoid muscle and the muscles of the rotator cuff _ two muscle groups in the shoulder that have directly to do with people lifting too much weight or using improper technique, " said Kathi Fairbend, a Weston physical therapist and ergonomic consultant.
