A common finding in cases of shoulder impingement is a loss of glenohumeral internal rotation. This loss of internal rotation, often referred to as glenohumeral internal rotation deficit (GIRD), promotes an upward and anterior shift of the humeral head into the acromion or coracoacromial ligament resulting in the impingement.
The ligamentous structure of the shoulder joint, the capsule, will often become stiffened or shortened over time due to daily/work activities, sporting activities (especially throwers), and those heavily involved in weight training (especially bodybuilders and powerlifters).
The common recommended stretch for posterior capsule stiffness is the “sleeper stretch”. This stretch is commonly performed in side lying with the downside arm at 90 degrees of flexion and then the shoulder is passively internally rotated until the optimal stretch is achieved.
Recent research shows that this position doesn’t actually produce any significant strain (stretch) to the posterior capsule making it ineffective for the intended purpose.
To effectively stretch the upper and middle posterio capsule, a position of 30 degrees of elevation in the scapular plane with internal rotation was more effective. To effectively stretch the upper and lower portions of the posterior capsule, the shoulder should be placed in 30 degrees of extension and then internally rotated.
This may explain some of the frustration experienced by many with posterior capsule stiffness and ongoing shoulder symptoms as their methods was simply ineffective. It wasn’t their lack of effort.
Source: The American Journal of Sports Medicine 36:2014-2022 (2008)
Bill