Purpose The purposes of this study were to (1) assess the inter-rater reliability and validity of 2 clinical assessment methods of categorizing scapular dyskinesis and (2) quantify the frequency of ...asymmetry of bilateral scapular motion in injured and uninjured shoulders by use of 3-dimensional (3D) kinematic analysis. Methods We evaluated 56 subjects, 35 with shoulder injury and 21 with no symptoms. Two blinded evaluators categorized the scapular motion of all subjects to determine inter-rater reliability using 2 observational methods (“yes/no” and “4 type”) to evaluate scapular dyskinesis. Subjects were also instrumented with electromagnetic receivers to assess bilateral 3D scapular kinematics to determine the presence of dyskinesis and establish criterion validity of the 2 methods. Results The inter-rater percent agreement and the degree of this agreement as measured by κ statistic showed that the yes/no method produced a higher inter-rater percent agreement (79%, κ = 0.40) than the 4-type method (61%, κ = 0.44). The yes/no method had a higher sensitivity (76%) and positive predictive value (74%) when compared with the 3D criterion. A χ2 analysis found significantly more multiple-plane asymmetries in symptomatic subjects (54%) in flexion compared with asymptomatic subjects (14%) ( P = .002). Conclusions The yes/no method allows multiple-plane asymmetries to be considered in clinical assessment and therefore renders this a good screening tool for the presence of scapular dyskinesis. Kinematic analysis shows that asymmetries are common in symptomatic and asymptomatic populations. Testing in flexion showed a higher frequency of multiple-plane scapular asymmetries in the symptomatic group. Clinical Relevance Identification of scapular dyskinesis is a key component of the shoulder examination. The clinician's ability to establish the presence or absence of scapular dyskinesis by observation is enhanced using a simple yes/no method especially when testing subjects in shoulder forward flexion. Although scapular asymmetries appear to be a prevalent finding, dyskinesis in the presence of shoulder symptoms should be considered a potential factor contributing to the dysfunction in the presence of shoulder symptoms should be considered a potential factor contributing to the dysfunction.
The second international consensus conference on the scapula was held in Lexington Kentucky. The purpose of the conference was to update, present and discuss the accumulated knowledge regarding ...scapular involvement in various shoulder injuries and highlight the clinical implications for the evaluation and treatment of shoulder injuries. The areas covered included the scapula and shoulder injury, the scapula and sports participation, clinical evaluation and interventions and known outcomes. Major conclusions were (1) scapular dyskinesis is present in a high percentage of most shoulder injuries; (2) the exact role of the dyskinesis in creating or exacerbating shoulder dysfunction is not clearly defined; (3) shoulder impingement symptoms are particularly affected by scapular dyskinesis; (4) scapular dyskinesis is most aptly viewed as a potential impairment to shoulder function; (5) treatment strategies for shoulder injury can be more effectively implemented by evaluation of the dyskinesis; (6) a reliable observational clinical evaluation method for dyskinesis is available and (7) rehabilitation programmes to restore scapular position and motion can be effective within a more comprehensive shoulder rehabilitation programme.
The importance of function of the central core of the body for stabilisation and force generation in all sports activities is being increasingly recognised. 'Core stability' is seen as being pivotal ...for efficient biomechanical function to maximise force generation and minimise joint loads in all types of activities ranging from running to throwing. However, there is less clarity about what exactly constitutes 'the core', either anatomically or physiologically, and physical evaluation of core function is also variable. 'Core stability' is defined as the ability to control the position and motion of the trunk over the pelvis to allow optimum production, transfer and control of force and motion to the terminal segment in integrated athletic activities. Core muscle activity is best understood as the pre-programmed integration of local, single-joint muscles and multi-joint muscles to provide stability and produce motion. This results in proximal stability for distal mobility, a proximal to distal patterning of generation of force, and the creation of interactive moments that move and protect distal joints. Evaluation of the core should be dynamic, and include evaluation of the specific functions (trunk control over the planted leg) and directions of motions (three-planar activity). Rehabilitation should include the restoring of the core itself, but also include the core as the base for extremity function.
Current concepts: scapular dyskinesis Kibler, W Ben; Sciascia, Aaron
British journal of sports medicine,
04/2010, Volume:
44, Issue:
5
Journal Article
Peer reviewed
The scapula serves many roles in order for proper shoulder function to occur. These roles include providing synchronous scapular rotation during humeral motion, serving as a stable base for rotator ...cuff activation and functioning as a link in the kinetic chain. Each role is vital to proper arm function and can only occur when the anatomy around the shoulder is uncompromised. The presence of bony and soft tissue injury as well as muscle weakness and inflexibility can alter the roles of the scapula and alter scapular resting position and/or dynamic motion. This altered scapular position/movement has been termed ‘scapular dyskinesis’. Although it occurs in a large number of shoulder injuries, it appears that scapular dyskinesis is a non-specific response to a painful condition in the shoulder rather than a specific response to certain glenohumeral pathology. The presence or absence of scapular dyskinesis needs to be determined during the clinical examination. An examination consisting of visual inspection of the scapular position at rest and during dynamic humeral movements, along with the performance of objective posture measurements and scapular corrective maneuvers, will help the clinician ascertain the extent to which the scapula is involved in the shoulder injury. Treatment of scapular dyskinesis should begin with optimised anatomy and then progress to the restoration of dynamic scapular stability by strengthening of the scapular stabilisers utilising kinetic chain-based rehabilitation protocols.
The overhead throwing motion is a complex activity that is achieved through activation of the kinetic chain. The kinetic chain refers to the linkage of multiple segments of the body that allows for ...transfer of forces and motion. The lower extremities and core provide a base of support, generating energy that is transferred eventually through the throwing arm and hand, resulting in release of the ball. The kinetic chain requires optimal anatomy, physiology, and mechanics and is involved in all 6 phases of overhead throwing: windup, stride, arm cocking, acceleration, deceleration, and follow-through. Breaks or deficits in the kinetic chain can lead to injury or decreased performance. Through an understanding of the mechanics and pathomechanics seen in each phase of throwing, the clinician can better evaluate and screen for potential kinetic chain deficits in the overhead throwing athlete. The purpose of this article is to review the biomechanics of the overhead throwing motion, the role of the kinetic chain in throwing, and the clinical evaluation and management of abnormal throwing mechanics and related injuries.
Optimal performance of the overhead throwing task requires precise mechanics that involve coordinated kinetic and kinematic chains to develop, transfer, and regulate the forces the body needs to ...withstand the inherent demands of the task and to allow optimal performance. These chains have been evaluated and the basic components, called nodes, have been identified. Impaired performance and/or injury, the DTS, is associated with alterations in the mechanics that are called pathomechanics. They can occur at multiple locations throughout the kinetic chain. They must be evaluated and treated as part of the overall problem. Observational analysis of the mechanics and pathomechanics using the node analysis method can be useful in highlighting areas of alteration that can be evaluated for anatomic injury or altered physiology. The comprehensive kinetic chain examination can evaluate sites of kinetic chain breakage, and a detailed shoulder examination can assess joint internal derangement of altered physiology that may contribute to the pathomechanics. Treatment of the DTS should be comprehensive, directed toward restoring physiology and mechanics and optimizing anatomy. This maximizes the body’s ability to develop normal mechanics to accomplish the overhead throwing task.
Purpose of Review
This review will outline scapular function in throwing, discuss scapular dyskinesis as an impairment of function that can be associated with throwing injuries and altered ...performance, and present an algorithm that encompasses guidelines for evaluation and can serve as a basis for treatment.
Recent Findings
Optimal scapular function is integral to optimal shoulder function. Multiple roles of the scapula in arm function and throwing have been identified while scapular dysfunction continues to be associated with various shoulder pathologies. Although scapular motion alterations may be common in overhead athletes, various reports have shown that identification and management of the alterations can result in improved rehabilitation and performance outcomes.
Summary
Baseball throwing occurs as the result of integrated, multisegmented, sequential joint motion, and muscle activation within the kinetic chain. The scapula is a key component link within the chain through its function to maximize the scapulohumeral rhythm and efficient throwing mechanics. Evaluation and management beginning with the scapula can produce improved outcomes related to shoulder pathology in overhead athletes.
Abstract In the 10 years since the current concept series entitled “The Disabled Throwing Shoulder: Spectrum of Pathology” was conceived and written, many studies have been reported that add much ...more information to the understanding of the disabled throwing shoulder (DTS). The editors of Arthroscopy and the authors of the original series believed that an update to the original series would be beneficial to provide an organized overview of current knowledge that could update the thought process regarding this problem, provide better assessment and treatment guidelines, and guide further research. A dedicated meeting, including current published researchers and experienced clinicians in this subject, was organized by the Shoulder Center of Kentucky. The meeting was organized around 5 areas of the DTS that were highlighted in the original series and appear to be key in creating the DTS spectrum and to understanding and treating the DTS: (1) the role of the kinetic chain; (2) the role and clinical evaluation of the scapula; (3) the role of deficits in glenohumeral rotation, glenohumeral internal rotation deficit, and total range-of-motion deficit in the causation of labral injury and DTS; (4) the role of superior labral (SLAP) injuries and rotator cuff injuries; and (5) the composition and progression of rehabilitation protocols for functional restoration of the DTS. The meeting consisted of presentations within each area, followed by discussions, and resulted in summaries regarding what is known in each area, what is not known but thought to be important, and strategies to implement and enlarge the knowledge base.
Purpose To analyze current literature reporting surgical treatment of SLAP lesions to examine the consistency of reported surgical details (surgical indications, surgical technique, and postoperative ...rehabilitation) that are deemed important for best treatment outcomes and to try to establish a consensus regarding treatment. Methods A systematic review of papers reporting surgical treatment of a SLAP lesion was performed. Each paper was analyzed for the description of (1) the arthroscopic indications for surgery; (2) surgical aspects including type, location, and number of anchors and sutures; (3) description of criteria for determination of completeness of the repair; and (4) postoperative rehabilitation details. These findings were also analyzed to determine whether a consensus could be developed regarding surgical treatment. Results Twenty-six papers were included, with 12 focused on isolated SLAP repair and 14 focused on combined SLAP repair with other lesions; 54% did not report indications for surgery. Reporting of the anchor/suture details was not consistent, with 35% reporting some variation of 12:00 placement but 31% not reporting the position of placement; 89% of papers did not report the criteria for determining completeness of the repair; 85% reported general postoperative rehabilitation guidelines, but only 4% reported in-depth details. Conclusions This review demonstrated a wide variability in the reported surgical aspects and that a relatively high percentage of papers did not report many of the details. This lack of precision and consistency makes analysis of individual papers and comparison between papers and their outcomes difficult and does not allow a consensus regarding current practice to be developed. These findings may be some of the factors responsible for the variability in treatment outcomes and suggest that efforts could be directed toward consistency in documenting and reporting surgical indications, surgical techniques, surgical endpoints, and efficacious rehabilitation programs. Level of Evidence Level IV, systematic review of level III-IV studies.
Background: Restoration of control of dynamic scapular motion by specific activation of the serratus anterior and lower trapezius muscles
is an important part of functional rehabilitation. This study ...evaluated activation of those muscles in specific exercises.
Hypothesis: Specific exercises will activate key scapular-stabilizing muscles in clinically significant amplitudes and patterns.
Study Design: Controlled laboratory study.
Methods: Muscle activation amplitudes and patterns were evaluated in the serratus anterior, upper trapezius, lower trapezius, anterior
deltoid, and posterior deltoid muscles with electromyography in symptomatic (n = 18) and asymptomatic (n = 21) subjects as
they executed the low row, inferior glide, lawnmower, and robbery exercises.
Results: There were no significant differences in muscle activation amplitude between groups. Muscle activation was moderate across
all of the exercises and varied slightly with the specific exercise. The serratus anterior and lower trapezius were activated
between 15% and 30% in all exercises. Upper trapezius activation was high (21%â36%) in the dynamic exercises (lawnmower and
robbery). Serratus anterior was activated first in the low row and last in the lawnmower and robbery. The upper trapezius
and lower trapezius were activated first in the lawnmower and robbery.
Conclusion: These specific exercises activate key scapular-stabilizing muscles at amplitudes that are known to increase muscle strength.
Clinical Relevance: These exercises can be used as part of a comprehensive rehabilitation program for restoration of shoulder function. They
activate the serratus anterior and lower trapeziusâkey muscles in dynamic shoulder controlâwhile variably activating the upper
trapezius. Activation patterns depended on scapular position resulting in variability of amplitude and activation sequencing
between exercises. Inferior glide and low row can be performed early in rehabilitation because of their limited range of motion,
while lawnmower and robbery, which require larger movements, can be instituted later in the sequence.
Keywords:
scapula
EMG
rehabilitation
muscle activation
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