Using the Scapular Retraction Test Evaluation of Apparent and Absolute Supraspinatus Strength in Patients With Shoulder Injury

Physical examination of patients with shoulder injury not involving full-thickness rotator cuff tears frequently demonstrates decreased abduction strength to manual muscle or dynamometer testing. It is assumed that the supraspina-tus muscle is most frequently involved in this weakness, and tests that evaluate supraspinatus strength are commonly used as measures of abduction strength. Strengthening of the muscles that demonstrate weakness on the clinical examination is usually prescribed as part of the rehabilitation toward return of shoulder function. There may be several reasons that muscles demonstrate weakness. Some factors, such as actual injury, disuse atrophy , and inhibition due to pain, are intrinsic to the muscle and create an absolute weakness. Other factors, such as lack of a stable base of origin or decreased facilitation by proxi-mal muscle activation patterns, are extrinsic to the muscle and create an apparent weakness, even though the muscle itself may be capable of developing strength. It is therefore important to accurately discover which muscles or body segments are involved in the demonstrated weakness so that rehabilitation can focus on those areas. Our clinical experience in evaluation and rehabilitation of patients with a combination of shoulder injury, demonstrated apparent supraspinatus strength deficits, and scapular dys-kinesis has suggested that improvement in demonstrated apparent strength can often be seen when patients correct Background: Physical examination of patients with shoulder injury not involving actual rotator cuff tears frequently demonstrates decreased rotator cuff strength on manual muscle testing. This decrease has been attributed to supraspinatus muscle weakness, but it may be owing to alterations in scapular position.