Weight training
Weight training exercises where the arms are elevated above shoulder height but in an internally rotated position such as the upright row have been suggested as a cause of subacromial impingement. Another common cause of Impingement syndrome is restrictions in the range movement of the scapulo-thoracic surfaces. Commonly, one or more ribs between rib 2 and rib 7/8 on the side of the impingement may jut out slightly and/or feel hard when the person springs on it or them. When this occurs, the scapula is raised and anteverted (angled forwards). This in turn pushes the acromion and the humeral head out of its usual anatomical position placing pressure downwards at the head of the humerus at the position of the nerve thus causing the impingement syndrome. This is visibly demonstrated by a slightly raised and protracted shoulder girdle. Note: the humerus anteverts in this position causing a more protrusive section of the humerus to press upwards towards the acromion.