The relationship between scapular position and glenohumeral joint range of motion has been studied with significant ramifications for clinicians who treat patients with shoulder range of motion loss and scapular dysfunction. Laudner et al. [10] reported an association between posterior shoulder tightness (horizontal adduction range of motion loss) and scapular dysfunction characterized by anterior scapular positioning in 40 professional baseball pitchers. Additionally, a review of the literature by Ludewig and Reynolds [11] described findings of changes in scapular upward rotation and posterior tilt in patients diagnosed with adhesive capsulitis and shoulder stiffness. Vermeulen et al. [12] did show improvements in scapular biomechanics with physical therapy improving glenohumeral range of motion and resultant scapular mechanics. Therefore, evaluating patients with scapular dysfunction as mentioned earlier in this chapter should include objective quantification of glenohumeral joint range of motion to determine its potential role in scapular dysfunction. This includes the use of a goniometer or inclinometer to assess shoulder external and internal range of motion in 90° of abduction with scapular stabilization [13] (Fig. 16.2). Additionally, the measurement of horizontal crossarm adduction is also important given its potential relationship to scapular dysfunction in the overhead athlete [10] (Fig. 16.3). A plethora of studies are present in the orthopedic and sports medicine literature profiling the normative range of motion patterns in elite overhead athletes [14–18]. These studies can provide important framework for clinicians regarding normal shoulder range of motion patterns to identify individuals who have range of motion deficiencies that may affect scapular mechanics.

Additional measurements have been used to measure flexibility of the pectoralis musculature [19]. Kluemper et al. [20] and Lynch et al. [21] have used a double square method in standing to quantify bilateral differences in the anterior shoulder and scapular position in swimmers. This clinical technique allows for rapid identification of anterior shoulder posture and can be done in the supine position as well. Ellenbecker et al. [22] have identified increased anterior shoulder posture in the dominant arm of elite tennis players using this method. Individuals presenting with increases in anterior shoulder posture receive specific interventions to improve pectoralis flexibility such as supine scapular retraction stretches on a foam roll (with and without therapist assistance) (Fig. 16.4a, b) as well as corner stretches [21, 23]. To address posterior shoulder tightness, research has shown the sleeper stretch to produce acute and longer-term improvements in shoulder internal rotation range of motion [24, 25] and is recommended for clinical use (Fig. 16.5). Use of the crossarm stretch (horizontal adduction) is also supported in the literature by McClure et al. [26], Moore et al. [27], and Ellenbecker et al. [28], with the later study showing up to 8° of internal rotation range of motion improvement following three, 30-s stretches using a contract-relax format and stretch strap (Fig. 16.6). Clinically, research has recently been published [29] highlighting the importance of scapular stabilization during the crossarm stretch performed by a physical therapist showing superior results with the addition of a medially directed stabilization force on the lateral border of the scapula and shoulder during the application of the crossarm adduction movement (Fig. 16.7).

In the early stage of scapular training, conscious muscle control of the scapular muscles may be necessary to improve proprioception and to normalize scapular resting position. A priority is first given toward the patient attaining active control of scapular orientation, facilitated by the therapist and then practiced by the patient. Depending on the dominant type of scapular dyskinesis, attention is given to correcting the scapula toward more posterior tilting, upward rotation, or external rotation. It was demonstrated in a three-dimensional scapular movement analysis study that it is possible to teach a normal subject to consistently reproduce movements of the scapula into posterior tilt and upward rotation [30]. In addition, De Mey et al. [31] showed higher electromyographical activity in the targeted muscles and in particular middle trapezius and lower trapezius during dynamic shoulder exercises when conscious correction of the scapular position was performed prior to the exercise. It is important to incorporate scapular orientation with spinal posture correction, especially in those patients who have a tendency to drift into a forward head posture, with an increasing thoracic kyphosis and protraction of the shoulder girdle. Patients are encouraged to perform this exercise repeatedly throughout the day, with the emphasis being on a change in postural habit. Memory joggers may be useful to ensure it becomes a habit [9].

Based on patient observation and the physical clinical exam, the clinician may decide to focus more on training of neuromuscular control (force-couple activation and co-contraction) during functional movements or on isolated muscle strength and balance training of the scapular muscles. The fundamental differences between both approaches might be the exercise selection. When focusing on motor control, low-load functional movement exercises should be chosen, mainly elevation exercises in variable planes, since the aim is to optimize neuromuscular control during daily functional activities. Moreover it has been suggested that high-load isolated training of individual muscles does not allow the nervous system to adapt to optimal movement strategies [2]. Motor control exercises should primarily focus on quality of movement and endurance, in more advanced stages of rehabilitation also on energy transfer and absorption [1, 2]. Scapular co-contraction may be trained in basic positions, movements, and exercises (e.g., simultaneous inferior glide, bilateral external rotation, and thoracic extension). As the shoulder girdle functions in both open- and closed-chain activities, the muscles should be trained to respond to both situations, by challenging the maintenance of the new scapular position under load, using weight-bearing and non-weight-bearing tasks of the upper limb. These should be consistent with the functional requirements of the patient. With respect to open-chain activities, Kibler et al. [32] described specific exercises for scapular control in the early phases of shoulder rehabilitation. The “low row,” “inferior glide,” “lawnmower,” and “robbery” exercises, as described in their paper, activate the key scapular-stabilizing muscles without putting high demands on the shoulder joint, making these exercises appropriate to use in early stages of nonoperative as well as in postoperative rehabilitation. Closed-chain exercises are believed to improve dynamic glenohumeral and scapulothoracic stability through stimulation of the intra- and periarticular proprioceptors and enhance co-contraction of the rotator cuff and scapular stabilizers. It should be noted, however, that closed-chain positions such as the “push-up” position or the “wall slide” exercise mainly activate the anterior scapular muscles such as serratus anterior and also pectoralis minor. These exercises should be selected with caution, to avoid activation of anterior muscles that might be shortened or hyperactive [33]. In these early stages of rehabilitation, the progression may benefit from additional taping and bracing; however literature is inconclusive regarding the effects of these interventions [34]. The use of neuromuscular electrical stimulation (NMES) may also be considered. NMES on the serratus anterior and lower trapezius has been shown to increase the acromiohumeral distance in healthy shoulders, suggesting a beneficial effect on scapular position for patients with subacromial pain syndrome [35].

If substantial deficits in muscle strength or muscle imbalances are identified, selective muscle training restoring strength and inter- and intramuscular balance may be warranted, performing high-load exercises isolating specific muscle groups. These exercises are often less functional (e.g., in prone- or side-lying positions) as a consequence of the specific goal of the exercise, particularly aiming at activating one specific muscle group [36, 37]. Functional exercises such as elevation will always activate more or less all scapular muscles and will never be able to isolate one muscle group. If weakness in one muscle is accompanied by hyperactivity in another one, restoring muscle balance is necessary with minimal activity of the hyperactive muscles. After muscle balance is restored, more general strengthening exercises for the scapular muscles may be used.

The selection of exercises may be based on many criteria, such as general guidelines from the literature, outcome studies showing evidence of specific exercise protocols, personal preference of the clinician, and functional relevance in view of the patient’s demands and expectations. Results from electromyographical studies on the activity of scapular muscles in healthy persons as well as in patients with upper quadrant pain and dysfunction have been a basis for recommendation for the choice of exercises during treatment of patients with shoulder or neck pain related to scapular dysfunction. Studies on patients illustrate specific scapular muscle dysfunctions in relation to shoulder or neck pain; studies on healthy persons justify the choice of exercises based on specific treatment goals. It is believed that performing exercises with the appropriate focus on specific muscle activation patterns may improve the quality of scapular motion and thus restore optimal movement patterns. Assuming the large variability in scapular dysfunction and abnormal scapular muscle recruitment patterns, exercises should always first focus on restoring the muscle balance. Based on current evidence and clinical experience, muscles that are often hyperactive are the upper trapezius, rhomboids, pectoralis minor, and levator scapulae, whereas a lack of activation has been found in the upper trapezius, rhomboids, middle trapezius, lower trapezius, and serratus anterior [38–40]. Indeed the role of upper trapezius and rhomboids in scapular dysfunction and shoulder pain is not clear yet, and it has been suggested that both hypercontracture and weakness might be present in a patient with upper quadrant pain and dysfunction [11, 41]. In view of these imbalances, exercises may be selected based on muscle balance ratios with lesser/more scapular muscle activity. Based on the available evidence [41, 42] and clinical experience, the clinically relevant balance ratios and most appropriate exercises are presented (Table 16.1).

From a clinical perspective, motor control deficits, muscle imbalances, and hyperactivity are not easy to examine or measure in an objective way, and often the clinician relies upon his visual observation skills to define normal versus abnormal scapular position and motion. Using the medial border of the scapula as the landmark for scapular orientation, three types of scapular malpositioning may be defined. Predominant inferior medial border prominence (type I) reflects a scapula that is too much anteriorly tilted. Underlying mechanisms may be flexibility deficits in the pectoralis minor and/or a dysfunction in the lower trapezius and/or serratus anterior, the force couple responsible for posterior tilt of the scapula. Exercises for type I should therefore focus on activating serratus anterior and lower trapezius. Exercises with a glenohumeral external rotation component have shown to increase activity in lower trapezius [36, 43]. In case the entire medial border is visible (type II), the scapula is positioned in too much internal rotation. Exercises should focus on external rotation of the scapula, activating the force couple trapezius/serratus anterior. Exercises performing retraction in the horizontal plane (with the arms elevated 90°) are most likely to enhance scapular external rotation and activating the three trapezius parts together with serratus anterior. These exercises may be performed in open (e.g., “horizontal abduction with ER”) as well as in closed (e.g., “from prone to side bridging”) kinetic chain. When scapular malpositioning is characterized by superior medial border prominence (type III), the scapula is too much downwardly rotated. Underlying mechanisms are contracture of levator or rhomboids and dysfunction in the upward rotation force couple including upper trapezius and serratus anterior with stabilizing components coming from middle and lower trapezius. There should be a focus on promoting upward rotation by performing exercises with the arms in higher elevation angles to put the scapula in a maximal upward rotation, like overhead shrugging and retraction [46].

Throughout the exercise program, proximal and distal links of the kinetic chain should be implemented. Creating diagonal patterns in open and closed chain by standing on the contralateral leg or extending one leg in the four-point kneeling position has shown to positively influence serratus anterior and middle and lower trapezius activity [47, 48]. Adding trunk rotation to exercises also promotes proper scapular alignment into posterior tilt and external rotation and increases lower trapezius activity and decreases upper/lower trapezius ratio [49]. Implementing upper limb functional patterns into the exercises allows focus on elbow, forearm, wrist, and hand movements during scapula-focused exercises.

Although the relevance of the scapula in normal shoulder function is well documented and therefore any rehabilitation program for the upper quadrant should include scapula-focused interventions, there are still many uncertainties and questions, and therefore clinicians as well as researchers should remain critical in their interpretation of research and clinical guidelines. Firstly, the cause-consequence between shoulder pain and scapular dyskinesis remains unclear. It is unclear whether the alterations found in scapular kinematics are compensatory or contributory to neck/shoulder pathology. Results from prospective studies investigating scapular dyskinesis as a possible risk factor show conflicting results [50–52]. According to a recent theory of pain adaptation, it is suggested that during episodes of pain, there is a redistribution of activity within and between muscles, which may have some benefit in the short term (protection from further pain or injury), but there is the potential for adverse long-term mechanical consequences to pain-sensitive tissues [53]. In view of this theory, scapular muscle dysfunction might be secondary to painful shoulder or neck conditions. Secondly, since scapular dyskinesis seems to be present also in a large proportion of a healthy population [54] and scapular asymmetry is considered to be “normal” in overhead athletes [1], the observed “abnormal” position and motion of the scapula may represent normal kinematic variability, reflecting the individual variety of coordination patterns to complete a task [2]. Therefore, it is imperative to put possible scapular dysfunction into the right perspective, linking the dyskinesis to the presence of symptoms [6]. Thirdly, when prescribing exercises “focusing on the scapula,” we should take into account that scapular exercises always include glenohumeral components. In most exercises with target on the scapula, the rotator cuff muscles are highly activated as a result of an external or internal rotation component during the exercise. It is therefore nearly impossible but also not desirable to markedly differentiate between “scapular” and “glenohumeral” exercises, but rather to focus on the integration of both links in the upper limb kinetic chain in a coordinated manner in the exercise program.

Evidence of scapular dysfunction in the overhead athlete is present in the literature. Oyama et al. [55] studied overhead athletes and found the dominant extremity to have greater amounts of scapular upward rotation, anterior tilt, and internal rotation. Additionally, the dominant side shoulder girdle was consistently more protracted. Cools et al. [56] similarly found significant scapular position and scapular muscle strength differences or asymmetries between the dominant and non-dominant extremity in elite junior tennis players. Significant muscular demands have been profiled in electromyographical studies for the tennis serve and ground strokes [57, 58], as well as for the overhead throwing motion [59]. These studies show the inherent demands on the scapular musculature needed for optimal stabilization and positioning particularly during the phases of late cocking and deceleration. Exercises that specifically focus on the positions of 90° shoulder external rotation and abduction (late cocking) as well as during late acceleration and follow-through are recommended. Ellenbecker et al. [60] provided a descriptive study of two commonly used plyometric exercises that recruit the serratus anterior, posterior rotator cuff, and lower trapezius at moderate to high levels and utilize biomechanical movement patterns that simulate those utilized by overhead athletes. Figures 16.8 and 16.9a–d profile those exercises for rotator cuff and scapular stabilization. A low-resistance/high-repetition base for these exercises is again emphasized. Carter et al. [61] have demonstrated increases in shoulder strength and throwing velocity after an 8-week program of rotator cuff and scapular exercises using both elastic- and plyometric-based exercises. Figure 16.10 shows a follow-through specific exercise using both elastic resistance and rhythmic stabilization applied to the dominant extremity in a throwing athlete that can be utilized. Further research is needed in this area to better understand the effects of scapular stabilization exercise on both performance enhancement and injury prevention.