Orthopedic Certified Specialist (OCS) Practice Exam

The choice of using the full-can position for strengthening the supraspinatus in patients with sub-acromial impingement syndrome is based on biomechanical principles and muscle activation patterns. In the full-can position, the arm is elevated in the scapular plane with the thumb pointing upward, which optimally positions the supraspinatus muscle to generate force while minimizing the risk of impingement.

In this position, the supraspinatus is effectively recruited through the full range of motion without excessively compressing the structures beneath the acromion. Additionally, this positioning helps to maintain the stability of the shoulder joint and encourages proper scapular mechanics, which are crucial for effective muscle performance and injury prevention.

Conversely, the empty-can position, which involves the thumb pointing down, is less favored because it can increase the likelihood of impingement due to altered shoulder mechanics and decreased force production of the supraspinatus. The neutral position may not effectively engage the supraspinatus or provide the necessary challenge for strengthening. The external rotation position focuses more on the rotator cuff muscles but does not specifically target the supraspinatus as effectively as the full-can position does.

In summary, the full-can position is considered the best for targeting the