These authors sought to identify the stretching positions that specifically applied the greatest passive tension on the posterior shoulder capsule by evaluating the elastic characteristics of posterior capsules and muscles in various stretching positions using ultrasound shear wave elastography in 9 fresh-frozen cadaver shoulders without osteoarthritis or rotator cuff tears.
All posterior shoulder tissues were preserved intact. Shear moduli of the middle and inferior posterior shoulder capsule and the posterior shoulder muscles were evaluated in combinations of glenohumeral
elevation planes and angles (frontal, sagittal, scapular; –30, 0, 30, 60, respectively). A 4-Nm torque for shoulder internal rotation or horizontal adduction was applied in each position.
They found that the middle posterior capsule was most effectively stretch by internal rotation at 30 of elevation in the scapular plane and cross body adduction at 60 of elevation. The inferior posterior shoulder capsule was most effectively stretched by internal rotation at 30 of flexion.
Comment: Posterior capsular tightness is a common finding on careful evaluation of the painful shoulder, although it is often overlooked by the casual observer. It can be noted by (a) limited cross body adduction, (b) limited internal rotation with the arm abducted, and (c) by limited reach up the back. As found in cadavers by the authors, we have found that the posterior capsule can be effectively stretched by cross body adduction (see this link) and the sleeper stretch (see this link).
