Sports Med 2008; 38 (5): 369-386

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 1. Laboratory Measurement of Scapular Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 2. Clinical Measurement of Scapular Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372 3. The Scapula in Sports Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 3.1 Adaptive Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 3.2 Scapulothoracic Muscle Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 3.3 Pathological Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 3.3.1 Impingement Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 3.3.2 Unstable Shoulder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 4. Conservative Management of Scapular Malposition – Rehabilitation . . . . . . . . . . . . . . . . . . . . . . . . . . 379 4.1 Flexibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 4.2 Strengthening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 4.3 Scapular Taping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 Despite the essential role played by the scapula in shoulder function, current Abstract concepts in shoulder training and treatment regularly neglect its contribution. The ‘scapular dyskinesis’ is an alteration of the normal scapular kinematics as part of scapulohumeral rhythm, which has been shown to be a nonspecific response to a host of proximal and distal shoulder injuries. The dyskinesis can react in many ways with shoulder motion and function to increase the dysfunction. Thoracic kyphosis, acromio-clavicular joint disorders, subacromial or internal impingement, instability or labral pathology can alter scapular kinematics. Indeed, alteration of scapular stabilizing muscle activation, inflexibility of the muscles and capsule-ligamentous complex around the shoulder may affect the resting position and motion of the scapula. Given the interest in the scapular positioning and patterns of motion, this article aims to give a detailed overview of the literature focusing on the role of the scapula within the shoulder complex through the sports context. Such an examination of the role of the scapula requires the description of the normal pattern of scapula motion during shoulder movement; this also implies the study of possible scapular adaptations with sports practice and scapular dyskinesis concomitant to fatigue, impingement and instability. Different methods of scapular positioning evaluation are gathered from the literature in order to offer to the therapist the possibility of detecting scapular asymmetries through clinical examinations. Furthermore, current concepts of rehabilitation dealing 370 Forthomme et al. with relieving symptoms associated with inflexibility, weakness or activation imbalance of the muscles are described. Repeating clinical assessments throughout the rehabilitation process highlights improvements and allows the therapist to actualize rationally his or her intervention. The return to the field must be accompanied by a transitory phase, which is conducive to integrating new instructions during sports gestures. On the basis of the possible scapular disturbance entailed in sports practice, a preventive approach that could be incorporated into training management is encouraged. The shoulder complex is involved in a great shoulder by improving the concavity-compression effect.[1,6,11] many sports and athletic activities requiring specific gestures.[1-7] Shoulder function represents a focus of The ‘second’ role of the scapula is to provide interest both for many sports medicine specialists adapted motion along the thoracic wall because the and for trainers. An understanding of shoulder patterns of scapular motion are related to the type of biomechanics is of premium importance, even more task being performed. For example, for the shoulder so since athletes who participate in repeated overinvolved in physical work, scapular retraction crehead activities appear to be most specifically at risk ates a stable base for tasks that require reaching, of developing shoulder pain.[2] pushing or pulling.[3,4,10,11,16] The ‘third’ role of the scapula in shoulder funcThe scapula plays an important role in normal tion is the elevation of the acromion to clear the shoulder function.[8-12] In sports in which demands acromion from the moving rotator cuff, so as to placed on the shoulder are extremely high, the qualidecrease impingement and coraco-acromial ty of movements depends on the interaction between arch compression.[6,8,10,13] scapular and glenohumeral kinematics. Abnormal The ‘fourth’ role of the scapula in shoulder funcscapular kinematics and associated muscle dysfunction is that of being a link in the proximal to distal tion are assumed to contribute to shoulder pain sequencing of velocity, energy and forces.[6,8,16] The pathology.[5,6,13] largest proportion of kinetic energy and force in the However, up until recently, the role of the scapu‘kinetic chain’ is derived from the larger proximal la in sports gesture, as well as in the clinical evaluabody segments (the legs, back and trunk).[8] The tion or treatment of shoulder disorders has received scapula, providing a stable and controlled platform little attention from researchers and clinicians.[5] regulating the forces, is pivotal and transfers the With the aim of describing more precisely the strong forces and high energy to the distal body motion capacity of the shoulder, the kinematic intersegments: the arm and the hand.[6,8,12,16] action between the scapula and the humerus was The intricate role of the scapula into the shoulder introduced by Codman[14] and termed ‘scapulomovements oblige the therapists to consider the humeral rhythm’.[14,15] pattern of motion and position of the scapula in the Kibler et al.[8-10] have summarized several roles frame of shoulder dysfunction. Set apart from the for the scapula function into the shoulder complex scapula’s normal status, ‘scapular dyskinesis’ is de(figure 1). The ‘primary’ role indicates that the fined as an observable alteration in the position of scapula moves in coordination with the moving huthe scapula and the patterns of scapular motion in merus, so that the instant centre of rotation is conrelation to the thoracic cage.[10,17] Several factors strained within a physiological pattern throughout might create these abnormal patterns and this alterathe full range of the shoulder motion.[6,10,11] The tion in position: a resting posture of excessive thoproper alignment of the glenoid allows optimum racic kyphosis associated with an increased cervical function of both the bony constraints and the muslordosis, fractures of the clavicle and acromio-clacles of the rotator cuff. The intrinsic muscles of the vicular joint injuries or athrosis can alter scapular rotator cuff provide dynamic stabilization of the kinematics.[10] Likewise, subacromial impinge© 2008 Adis Data Information BV. All rights reserved. Sports Med 2008; 38 (5) Scapular Positioning in Athlete’s Shoulder 371 ment of the shoulder dysfunction with which the patient presents. 1. Laboratory Measurement of Scapular Kinematics Laboratory measurements of scapular displacements are typically capable of quantifying the scapular kinematics 3-dimensionally (3-D).[28,29] Parameters such as the type of instrumentation (electromagnetic tracking device,[4,28,29] magnetic resonance-based techniques,[21] Moiré topography,[17] reconstruction from radiographic assessment,[30,31] fresh frozen cadaver shoulder experimentation[1,32]), rotation matrix used, anatomical body landmarks, local reference system orientation, specific task requirements and planes of arm elevation (cardinal vs scapular) have differed widely across studies according to the goal pursued.[10,15,29,31-35] Recently, with the aim to facilitate and encourage communication among researchers or clinicians, the International Society of Biomechanics is recommending use of the standardized description of scapular motion, anatomical landmarks, local coordinate axes and Euler angle sequences for angle calculation.[34,36] The scapula moves simultaneously around the following three axes of motion (figure 2):[28,29,37,38] Efficiency of sport gesture