Tim's Paper2

A New Clinical Method of Measuring Posterior Shoulder Tightness: The Intertester and Intratester Reliability and its Application to Baseball Pitchers

Timothy Roy P.T.-Assistant Director, Eastside Sports Physical Therapy, P.C.

Timothy F. Tyler M.S., P.T., A.T.C.- Senior Physical Therapist, Clinical Coordinator of Education, Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital, New York, NY.

Stephen J. Nicholas M.D.-Assistant Director, Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital, New York, NY. Team Physician Hofstra University and NY Jets Football Club.

Gilbert W. Gleim PhD - Director of Research, Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital, New York, NY.

Published in the Journal of Orthopedic & Sports Physical Therapy

May, 1999

Clinical Relevancy

Clinically, much attention has been given to how a tight posterior shoulder complex might affect normal glenohumeral arthrokinematics and the need for certain athletes to stretch the structures of the posterior shoulder. However, clinicians have yet to produce a reliable method of measuring posterior shoulder structure tightness to date.

Abstract

Posterior shoulder tightness has been linked to anterior humeral head translation and decreased internal rotation (IR). The reliability of an objective assessment of posterior shoulder tightness has yet to be established in the literature. The purpose of this study is to present a new objective method of measuring posterior shoulder tightness, define the intratester and intertester reliability of the measurement and assess its construct validity. The measurement is made in the side lying position with the shoulder in neutral rotation, scapula stabilized manually, and distance from the elbow to the table assessed. Five repeat measurements were made using a standardized protocol on 21 controls to determine intratester reliability. To determine intertester reliability, two testers blinded to the measurement performed repeat trials on 49 shoulders. Twenty-two intercollegiate baseball pitchers were measured to evaluate the construct validity of the measurement. Measurements of posterior shoulder tightness performed by the same physical therapist had high reliability (ICC Dominant = .92, Nondominant = .95). Intertester measures revealed no difference between the means of the testers with r = 0.679, P < .001. Pitchers had reduced IR and increased ER ROM compared to controls (P < .01). Pitchers had significantly greater posterior shoulder tightness compared to controls (P < .001) and manifested a significant correlation to decreased internal rotation (r = -.61, P < .001) not evident in controls. Measurement of posterior shoulder tightness using this technique is objective and reliable when made by the same physical therapist. Validity of this measurement is supported from the observation of athletes thought to have tight posterior structures. The relationship of this measurement to patients diagnosed with shoulder impingement syndrome awaits testing.

New Measurement of Posterior Shoulder Tightness

Classically, the supine horizontal flexion (cross-chest adduction) position has been thought of as the "gold standard" for assessing posterior shoulder tightness. Our proposed objective measurement of posterior shoulder tightness is taken in the side lying position on a plinth. Male subjects have their shirts off for the test while female subjects are measured in a "sportsbra". The subject lies approximately one-half the length of their humerus away from the edge of the plinth. The subject’s knees and hips are passively bent to 90° angles and the patient lies in such a way that they remain on the table. The subject is aligned with bilateral acromion perpendicular to the plinth. The non-tested extremity is placed under the subject’s head. The spine is maintained in neutral flexion/extension and rotation. Proper positioning of the subject is crucial to a reliable measure (Fig. 1). The medial epicondyle of the humerus is marked with a skin pencil.

The tester positions themselves facing the subject. The tested extremity is grasped just distal to the epicondyles of the elbow. The humerus is passively moved into the starting position of 90° of abduction with the humerus in neutral rotation. At this point the scapula is grasped at the lateral border and stabilized in the retracted position (Fig 2). While maintaining the position of the scapula, the humerus is then passively and gently lowered into a horizontally adducted position with neutral rotation. The humerus is lowered until the motion has ceased or there is rotation of the humerus. The test is aborted and restarted if the subject is unable to relax or if the scapula is unable to be stabilized effectively.

At the end of the posterior shoulder range of motion, a recorder places a 60cm carpenter’s square perpendicular to the table and next to the marked medial epicondyle. The level of the inferior border of the medial epicondyle is marked on the carpenter’s square by the recorder (Fig 3). This mark charts the distance from the plinth to the medial epicondyle. The distance from the bottom of the square to the mark identifying the medial epicondyle is then measured and recorded in centimeters by the recorder. This distance measured indicates the amount of flexibility to the posterior shoulder. A greater distance between the medial epicondyle and the plinth is indicative of less flexibility to the posterior shoulder. Conversely, the closer the medial epicondyle falls to the table (smaller distance), the more flexible the posterior shoulder is. This measurement is taken bilaterally.

Fig. 1 Fig. 2

Fig 3.

Presented at Sports Section of APTA Combined Sections Meeting in Seattle, Washington in Feb, 1999

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