Shoulder impingement syndrome occurs as the result of chronic and repetitive compression or “impingement” of the rotator-cuff tendons in the shoulder, causing pain and movement impairments. It can also be caused by an injury to the shoulder. People who perform repetitive or overhead arm movements, such as manual laborers or athletes, are most at risk for developing a shoulder impingement. Poor posture can also contribute to its development. If left untreated, a shoulder impingement can lead to more serious conditions, such as a rotator cuff tear. Individuals with shoulder impingement syndrome may experience: restriction in shoulder motion with associated pain and weakness in movement patterns, such as reaching overhead, behind the body, or out to the side. Pain usually radiates from the front of the shoulder to the side of the arm.