Scapular Dyskinesis: A Narrative Review of Biomechanics, Clinical Assessment, and Physiotherapy Interventions

The shoulder girdle relies on coordinated motion across multiple joints and muscles to enable efficient upper‑limb function [1]. The scapula anchors the arm to the trunk and, through the scapulohumeral rhythm, contributes critically to shoulder mobility and stability [2]. Scapular dyskinesis (SD) refers to deviations from normal scapular position or motion that commonly accompany other shoulder pathologies (e.g., rotator cuff disease, instability, impingement) [3,4]. SD more commonly presents not as a primary disorder but as a secondary manifestation of other shoulder pathologies, such as acromioclavicular joint trauma, rotator cuff tears, clavicular fractures, subacromial impingement, multidirectional shoulder instability, and labral lesions [5-11]. Accurate clinical assessment and treatment planning should target the underlying drivers of dyskinesis-whether motor control deficits, muscle weakness, or soft‑tissue restriction-rather than treating the scapula as an isolated problem [12,13].

This narrative review summarises recent literature on the biomechanics, clinical assessment and physiotherapy management of scapular dyskinesis; searches were performed in PubMed, Scopus, Google Scholar, Web of Science and additional papers were identified by screening reference lists, with studies selected purposively for relevance to clinical practice.

 Scapular Kinematics and Muscular Interactions

Scapular motion comprises elevation/depression, protraction/retraction and upward/downward rotation, produced by coordinated activity of periscapular muscles (trapezius, serratus anterior, rhomboids, levator scapulae, pectoralis minor). These muscles act in force couples to position the scapula and maintain a stable base for glenohumeral motion. Dysfunctional timing or relative weakness-commonly an overactive upper trapezius with reduced lower trapezius and serratus anterior activation-disrupts upward rotation and posterior tilt, predisposing to inefficient movement patterns and secondary shoulder pathology [14,15].

Scapular translational movements describe the scapula’s gliding across the thoracic wall in various combinations [16]. These glides may occur in a mediolateral direction or along the inferior–superior axis. Periscapular muscles responsible for producing these movements include the trapezius, serratus anterior, rhomboids, levator scapulae and pectoralis minor [17]. The trapezius is a primary scapular stabiliser and is conventionally divided into three parts: the upper, middle and lower fibres [18]. The scapular retraction and abduction necessary for arm elevation are largely dependent on trapezius activation [19]. While upper trapezius activation predominantly contributes to upward rotation, activity of the lower and middle‑medial fibres supports medial translation and external rotation. The lower trapezius assumes a stabilising role for the scapula during full arm elevation and throughout the subsequent lowering phase.

The serratus anterior is another key muscle for effective scapulothoracic motion. Like the trapezius, it is conventionally described as having upper, middle and lower portions. By maintaining the scapula closely opposed and aligned to the thoracic wall, it limits excessive internal rotation, particularly during forward‑reaching activities. From a biomechanical perspective, it contributes to external rotation of the shoulder girdle; activation of its lower fibres facilitates upward rotation. Thus, healthy scapular movement and stability in the coronal plane are largely dependent on serratus anterior performance. Indeed, the serratus anterior and trapezius act synchronously to produce scapular upward rotation and posterior tilt.

The rhomboid major and minor complement the actions of the trapezius, contributing significantly to the scapula’s mediolateral translation. The co‑activation of the rhomboids with the middle trapezius forms an important force couple that supports both scapular stability and mobility. Although a 2:1 humerus-to-scapula ratio is often cited, the scapulohumeral rhythm varies substantially with movement plane and phase. Contemporary studies using bone‑fixed markers and dynamic imaging show plane‑dependent ratios and underscore that scapular kinematics are dynamic and context‑sensitive rather than constant. Clinically, this means abnormal scapular motion should be interpreted relative to the movement tested, not by a single fixed ratio [20,21].

SD is defined as a deviation of the scapula from its normal position or movement. Common accompanying clinical features may include prominence of the scapula’s medial border and inferior angle, early scapular elevation due to inadequate upward rotation, and insufficient downward rotation during arm lowering. Periscapular muscle weakness is implicated in SD; commonly an overactive upper trapezius occurs alongside reduced activation of the lower trapezius and serratus anterior (Figure 1). Although a definitive direct correlation between shoulder pathologies and SD has not been established, studies have reported that approximately 68–100% of individuals with a recognised shoulder pathology also present with SD.

Epidemiology

Neck and shoulder pain are common in the general population, with reported prevalence estimates ranging from 6.7% to 66.7%. SD is commonly observed in patients presenting with these complaints and is frequently accompanied by periscapular muscle weakness and shoulder instability. SD has been associated with a variety of shoulder pathologies, including rotator cuff disorders, glenohumeral instability, subacromial impingement and labral lesions. Furthermore, SD is not limited to individuals with painful shoulders; it may also be encountered at a significant frequency in the general population [22]. Indeed, a study of 40 healthy, university‑aged volunteers reported the presence of SD in 68% of participants.

Athletes are at greater risk of sustaining shoulder injuries than the general population. Risk is markedly increased in athletes engaged in sports that involve frequent overhead activities (e.g. baseball, tennis, volleyball, handball, swimming) [23]. In Burn et al.'s systematic review assessing the prevalence of SD in athletes, the prevalence was reported as 54.5% in overhead athletes and 33.3% in non‑overhead sports. Moreover, athletes with SD have an approximately 43% higher risk of developing subsequent shoulder pain compared with those without SD [24]. Postural factors are also important: increased thoracic kyphosis and cervical lordosis can alter the scapula’s resting position, thereby increasing susceptibility to SD [25]. Specific training regimens employed in athletes may induce core‑muscle imbalances, thereby altering spinal curvatures and increasing soft‑tissue tension; this, in turn, creates a substrate that predisposes to SD.

Another at‑risk group for shoulder and neck disorders comprises individuals who use computers for prolonged periods [26]. It is thought that faulty sitting posture also contributes to this condition. Evidence indicates that the dominant upper limb is more frequently affected by SD and shoulder injuries; likely mechanisms include overuse, muscle imbalances and differences in range of motion (ROM) [27-29]. Furthermore, in a study by Picco et al. examining scapular kinematics, healthy females were reported to exhibit reduced posterior tilt compared with males at high elevation angles, which the authors suggested may increase the risk of SD and shoulder pathology in women [30]. Obesity and advanced age are additional risk factors for shoulder pain [31,32].

Scapular Dyskinesis: Biomechanical Foundations and Clinical Implications

SD, while commonly regarded as a non‑specific adaptive response rather than a phenomenon unique to shoulder pathology, disrupts the scapula’s normal kinematics and stability-both of which are critical for shoulder function. However, the scapula provides a synchronous, coordinated movement pattern with the glenohumeral joint during upper‑limb actions, both facilitating glenohumeral mobility and supplying the stable base required for that mobility. Disruption of this coordination adversely affects load distribution and movement efficiency within the shoulder complex, thereby contributing to the persistence of symptoms [33].

Pathologies commonly observed concomitantly with SD include subacromial impingement, glenohumeral instability and rotator‑cuff injuries, labral tears and acromioclavicular (AC) joint injuries, as well as clinical presentations such as back, neck and shoulder pain. Subacromial impingement is associated with a reduction of the subacromial space and causes pain and mechanical limitation during arm elevation; this condition can disrupt the scapulohumeral rhythm and precipitate SD. In the presence of impingement, increased scapular protraction, diminished upward rotation and increased anterior tilt are observed, typically alongside overactivity of the upper trapezius and insufficient activation of the lower trapezius and serratus anterior. These patterns further narrow the subacromial space, perpetuating a vicious cycle; they are consistent with Kibler Type III dyskinesis [34]. Rotator‑cuff pathologies are a leading cause of shoulder pain and functional impairment [35]. Weakness or tearing of the surrounding muscles may result from various causes, including direct trauma, disuse atrophy or pain‑related reflex inhibition. Excessive scapular protraction associated with SD may reduce rotator‑cuff strength. In clinical assessment, the Scapular Retraction Test (SRT) and the Scapular Assistance Test (SAT) are useful for identifying rotator‑cuff strength deficits and for determining whether manual support of the scapula increases that strength; notably, the SRT can aid in differentiating suspected full‑thickness tears. Visual appraisal of abnormal scapular position and movement may also demonstrate the typical SD patterns associated with rotator‑cuff pathology (for example, Type II). The labrum is a key structure that contributes to the stability of the glenohumeral joint [36]. Injuries to the labrum, particularly SLAP‑type tears, can compromise shoulder stability and disrupt the normal scapulohumeral rhythm. SLAP tears and other labral lesions have been reported to result in deficits of glenohumeral internal rotation, which in turn adversely affect scapulohumeral kinematics [37]. Ultimately, alterations in movement patterns and loss of stability present as an excessive tendency toward scapular protraction, thereby creating the substrate for the development of scapular dyskinesis. A study investigated the prevalence of SD in individuals with back, neck and shoulder pain and examined the relationship between SD, pain severity and muscle tightness. SD was identified in the clinical assessment using dynamic scapular observation and standardised tests, while pain intensity and the presence of muscle shortening/tension in periscapular structures (pectoralis minor, upper trapezius–levator scapulae complex and pectoral muscles) were additionally measured. The findings demonstrated a high prevalence of SD in this cohort; when SD was present, pain scores were higher and muscle tightness more pronounced. In particular, tendencies toward scapular protraction and anterior tilt were more frequently observed in association with pectoralis minor shortening and increased thoracic kyphosis. The authors reported a significant association between SD, pain severity and muscle tightness, emphasising that SD is a common and clinically relevant finding in patients presenting with back–neck–shoulder pain [38]. SD has also been reported to increase the future risk of shoulder pain by approximately 43% in asymptomatic athletes.

Current Physiotherapy Approaches

Treatment is centred on restoring normal scapular kinematics through targeted exercise and manual‑therapy techniques. The primary goal of SD treatment is to restore appropriate scapular position and dynamics. Standard care comprises conservative interventions aimed at optimising scapular kinematics; surgical intervention is reserved only for concomitant pathologies that require operative management.

Conservative treatment can broadly be divided into two categories: (1) interventions aimed at increasing flexibility/mobility, and (2) exercises focused on improving scapular stabilisation and motor control. The combined application of these two approaches helps to optimise scapular kinematics by reducing unnecessary traction forces acting on the scapula. To devise an effective management plan, it is essential to distinguish whether the primary driver of SD is impaired muscle performance and motor control or loss of flexibility in the surrounding periscapular soft tissues. If the problem lies in muscle control/performance, strengthening and motor‑control‑focused interventions are recommended; these enhance proprioception and muscle force, thereby supporting scapular stability [39].

In strengthening programmes, the principal targets are the trapezius-particularly its lower fibres-and the serratus anterior. The lower trapezius aids positional stabilisation of the scapula, while the serratus anterior is pivotal for external rotation and posterior tilt. Push‑up variations performed on a stable surface, which have been shown to enhance serratus anterior activation and control, are therefore beneficial. Shoulder‑shrug exercises incorporating an upward‑rotation component are recommended to activate both the upper and lower fibres of the trapezius. For optimal gains, it is important that the patient develops active control of the periscapular musculature before progressing to loaded exercises. Once control of the target muscles has been achieved, emphasis may shift to strength training while maintaining correct technique.

A randomised controlled trial involving 44 patients with subacromial impingement syndrome (SIS) and SD demonstrated that adding scapular stabilisation exercises (SSE) to a standard physiotherapy programme significantly improved outcome. After four weeks, the SSE group showed superior results (p<0.05), with 95% resolution of dyskinesis (compared to 50% in the control group), significant gains in periscapular muscle strength, and greater reductions in pain and disability scores. These findings support SSE as an effective complementary approach to standard physiotherapy for improving scapular control, muscle performance, and overall function in this patient population [40].

Shire [41] conducted a systematic review and meta‑analysis of six randomised controlled trials - four comparing specific scapular exercise strategies with general shoulder exercises, and two evaluating a proprioceptive‑focused strategy. They reported no consistent differences between treatment groups in terms of pain or function. Five trials were judged to provide moderate‑quality evidence and one to provide low‑quality evidence. Consequently, the authors concluded that there is insufficient evidence to either support or refute the efficacy of specific resisted scapular exercise strategies in the rehabilitation of SIS. Based on these findings, our clinical approach is to avoid overemphasising scapular kinematics and instead focus on strengthening the rotator‑cuff and scapulothoracic muscle systems.

A systematic review and meta‑analysis of 11 randomized controlled trials (n=594), published up to July 2021, evaluated scapula‑focused interventions (mobilisation, muscle re‑training, stretching, strengthening and stabilisation). The pooled results demonstrated significant reductions in shoulder pain (p=0.008) and improvements in shoulder function (p=0.008) for groups receiving scapula‑focused exercises. However, there was no significant change in measured scapular position at 0°, 45° or 90° (p>0.05). The authors conclude that scapula‑focused exercise programmes improve pain and function in individuals with scapular dyskinesis, but did not alter static scapular position; the authors recommend larger, longer‑term, high‑quality trials to confirm these findings [42].

Another systematic review and meta‑analysis of eight randomised and crossover trials (n=346) published since 2000 investigated the efficacy of scapular therapeutic exercises in patients with shoulder pain. The findings indicated a significant improvement in shoulder function (p=0.03) compared with other interventions, particularly when exercise programmes lasted at least six weeks and involved no more than 30 repetitions per exercise. However, no significant difference was found in pain reduction (p=0.13). The authors concluded that scapular exercises are effective for enhancing shoulder function, with optimal results achieved through appropriate duration and repetition, but their impact on pain relief is limited [43].

In a study of women aged 40–65 examined the relationship between scapular stabiliser strength and scapular position using the Lateral Scapular Slide Test at three humeral positions. These findings underscore significant positive correlations between muscle strength and scapular alignment across all tested muscles, with position‑dependent dominance of specific stabilisers - the serratus anterior and upper trapezius exerted greatest influence on the inferior scapular region, the lower trapezius most strongly determined mediolateral scapular position in neutral, the middle trapezius was most influential at 45° abduction, and the serratus anterior predominated at 90° abduction — findings that underscore the clinical importance of designing rehabilitation programmes that target the specific periscapular muscles most relevant to the patient’s problematic functional range [44].