Scapular positioning and movement in unimpaired shoulders, shoulder impingement syndrome, and glenohumeral instability

Prevalence of shoulder pain in Swedish flatwater kayakers and its relation to range of motion and scapula stability of the shoulder joint

Few studies have investigated the incidence of injuries in kayakers. The aim was to study the prevalence of shoulder pain in competitive flatwater kayakers and to evaluate any differences in range of motion or scapula stability of the shoulder joint among kayakers with or without the history of shoulder pain. Thirty-one kayakers were participated in the study, and a questionnaire including background data was used. Shoulder range of motion was measured with a goniometer, and the participants were observed for scapula dyskinesis in flexion and abduction. Of the participating kayakers, 54.8% (n = 17) had experienced shoulder pain. Kayakers who had experienced shoulder pain showed a significantly lower degree of internal rotational range of motion versus kayakers with no reported shoulder pain, with a mean degree of internal rotation in the right shoulder 49.3 vs. 60.0 (P = 0.017) and the left shoulder 51.9 vs. 66.0 (P = 0.000). Kayakers who had experienced shoulder pain were also observed with a scapular dyskinesis (n = 15 of 17 kayakers) to a significantly higher degree (P = 0.001) than kayakers with no reported shoulder pain. Findings suggest that screening for scapular dyskinesis and testing for rotational range of motion in the shoulder joint is essential in order to treat and maybe prevent shoulder pain in kayakers.

Glenoid version and inclination are risk factors for anterior shoulder dislocation

HYPOTHESIS

Although the contribution of the capsuloligamentous structures and dynamic muscle balance to shoulder stability has been well documented, the role of the osseous anatomy of the glenoid has not been thoroughly evaluated. This study investigated glenoid version and inclination in patients with a documented anterior shoulder dislocation and compared it with a control group. We hypothesized that patients with a prior anterior dislocation would have more anterior version and increased inferior inclination of the glenoid.

MATERIALS AND METHODS

Patients aged younger than 40 years who underwent arthroscopic shoulder stabilization (study group) were compared with patients (control group) who had previously undergone magnetic resonance imaging (MRI) for a different shoulder condition. Version was measured on axial images, and inclination was measured on coronal images of a T2-weighted spin-echo scan. The MRIs of 128 study group patients (mean age, 24.5 ± 8.6 years) with a confirmed traumatic anterior shoulder dislocation were compared with the MRIs of 130 control group patients (mean age, 30.9 ± 7 years).

RESULTS

The mean version in the study group was -1.7° ± 4.5° (retroversion); the mean inclination was 1.6° ± 5.9° (inferior). The mean version in the control group was -5.8° ± 4.6° (retroversion); the mean inclination was -4.0° ± 6.8° (superior). The between-group differences were significant for version (P = .00001) and inclination (P = .00001).

CONCLUSIONS

The results of this study strongly suggest that glenoid version and inclination are significantly increased in patients with established anterior shoulder instability compared with a matched control group.

The effect of trunk rotation during shoulder exercises on the activity of the scapular muscle and scapular kinematics

BACKGROUND

In patients with shoulder disease, kinetic chain exercises including hip or trunk movement are recommended. However, the actual muscle activation and scapular kinematics of these exercises are not known. The purpose of this study was to examine the effect of trunk rotation on shoulder exercises that are devised to improve scapular function.

METHODS

Thirteen healthy young men participated in this study. Scaption, external rotation in the first and second positions, and prone scapular retraction at 45°, 90°, and 145° of shoulder abduction were performed with and without trunk rotation. Electromyography was used to assess the scapular muscle activity of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA), and electromagnetic motion capture was used to assess scapular motion. The muscle activity ratio, which is the activity of the UT to the MT, LT, and SA, was calculated. These data were compared between 2 conditions (with and without trunk rotation) for each exercise.

RESULTS

Adding trunk rotation to scaption, the first external rotation, and the second external rotation significantly increased scapular external rotation and posterior tilt, and all 3 exercises increased LT activation. In addition, trunk rotation with scapular retraction at 90° and 145° of shoulder abduction significantly decreased the UT/LT ratio.

CONCLUSIONS

Our findings suggest that shoulder exercises with trunk rotation in this study may be effective in patients who have difficulty in enhancing LT activity and suppressing excessive activation of the UT or in cases in which a decreased scapular external rotation or posterior tilt is observed.

Multidirectional instability of the shoulder: biomechanics, clinical presentation, and treatment strategies

Multidirectional instability (MDI) of the shoulder is a condition where the dislocation occurs in more than one direction with minimal or no causative trauma. Its pathoanatomy is complex and characterized by a redundant capsule, resulting in increased glenohumeral joint volume. The fact that several further factors may contribute to symptom onset complicates the diagnosis and hampers the identification of a therapeutic approach suitable for all cases. There is general agreement that the initial treatment should be conservative and that surgery should be reserved for patients who have not responded to an ad hoc rehabilitation program. We review the biomechanics, clinical presentation, and treatment strategies of shoulder MDI.

Rehabilitation Exercises to Induce Balanced Scapular Muscle Activity in an Anti-gravity Posture

[Purpose] The purpose of this study was to compare the intramuscular balance ratios of the upper trapezius muscle (UT) and the lower trapezius muscle (LT), and the intermuscular balance ratios of the UT and the serratus anterior muscle (SA) among prone extension (ProExt), prone horizontal abduction with external rotation (ProHAbd), forward flexion in the side-lying position (SideFlex), side-lying external rotation (SideEr), shoulder flexion with glenohumeral horizontal abduction load (FlexBand), and shoulder flexion with glenohumeral horizontal adduction load (FlexBall) in the standing posture. [Methods] The electromyographic (EMG) activities of the UT, LT and SA were measured during the tasks. The percentage of maximum voluntary isometric contraction (%MVIC) was calculated for each muscle, and the UT/LT ratios and the UT/SA ratios were compared among the tasks. [Results] The UT/LT ratio with the FlexBand was not significantly different from those of the four exercises in the side-lying and prone postures. The UT/SA ratio with the FlexBall demonstrated appropriate balanced activity. [Conclusion] In an anti-gravity posture, we recommend the FlexBand and the FlexBall for inducing balanced UT/LT and UT/SA ratios, respectively.

Scapular dyskinesis is detrimental to shoulder tendon properties and joint mechanics in a rat model

Shoulder tendon injuries are frequently seen in the presence of abnormal scapular motion, termed scapular dyskinesis. The cause and effect relationship between scapular dyskinesis and shoulder injury has not been directly defined. We developed and used an animal model to examine the initiation and progression of pathological changes in the rotator cuff and biceps tendon. Sixty male Sprague-Dawley rats were randomized into two groups: nerve transection (to induce scapular dyskinesis, SD) or sham nerve transection (control). The animals were euthanized 4 and 8 weeks after surgery. Shoulder function and passive joint mechanics were evaluated over time. Tendon mechanical, histological, organizational, and compositional properties were evaluated at both time points. Gross observation demonstrated alterations in scapular motion, consistent with scapular "winging." Shoulder function, passive internal range of motion, and tendon mechanical properties were significantly altered. Histology results, consistent with tendon pathology (rounded cell shape and increased cell density), were observed, and protein expression of collagen III and decorin was altered. This study presents a new model of scapular dyskinesis that can rigorously evaluate cause and effect relationships in a controlled manner. Our results identify scapular dyskinesis as a causative mechanical mechanism for shoulder tendon pathology.

Overuse activity in the presence of scapular dyskinesis leads to shoulder tendon damage in a rat model

Shoulder tendon injuries are common clinical conditions and are a significant source of pain and dysfunction. These conditions are more common in individuals who perform repetitive overhead activities and in individuals who have abnormal scapular kinematics, termed scapular dyskinesis (SD). However, the long term consequences associated with overuse activity in the presence of SD are unknown. Therefore, the objective of this study was to determine the effect of overuse in combination with SD on joint mechanics and properties of the rotator cuff and biceps tendons. A rat model of scapular dyskinesis was used. Ninety adult male Sprague-Dawley rats (400-450 g) were randomized into three groups: nerve transection (SD), sham nerve transection + overuse (OV), or nerve transection + overuse (SD + OV). Rats were sacrificed at 2, 4, and 8 weeks after surgery. Shoulder function and passive joint mechanics were evaluated over time and tendon properties (mechanical, histological, organizational, and compositional) were measured. Results demonstrated that overuse activity and SD are each independently detrimental to tendon properties (e.g., diminished mechanical properties, disorganized collagen). However, tendon damage caused by the addition of overuse may be worse, with more parameters altered, than damage caused by the addition of SD. This study helps define the mechanical mechanisms leading to tendon damage and provides a framework for distinguishing treatment strategies for active patients and those with abnormal scapular mechanics.

Reliability and precision of 3D wireless measurement of scapular kinematics

To direct interventions aimed at improving scapular position and motion in shoulder pathologies, a clinically feasible, objective, sensitive and reliable assessment of scapular dyskinesis is needed. The aim of this study is to evaluate the intra- and inter-observer reliability and the precision of 3D scapula kinematics measurement using wireless sensors of an inertial and magnetic measurement system (IMMS). Scapular kinematics during humerus anteflexion and abduction of 20 subjects without shoulder pathologies were measured twice by two observers at two different days, using IMMS. Similar movement patterns and corresponding high intraclass correlation coefficients were found within (intra) and between (inter) observers, especially for scapular retraction/protraction (0.65-0.85) and medio/lateral rotation (0.56-0.91). Lowest reliability and highest difference in range of motion were observed for anterior/posterior tilt. Medio/lateral rotation and anterior/posterior tilt showed a high precision, with standard error of measurement being mostly below 5°. The inter-observer measurements of retraction/protraction showed lowest precision, reflected in systematic differences. This is caused by an offset in anatomical calibration of the sensors. IMMS enables easy and objective measurement of 3D scapula kinematics. Further research in a patient population should focus on clinical feasibility and validity for measurement of scapular dyskinesis. This would include the application of a scapula locator to enhance anatomical calibration.

Physiotherapy assessment of patients with rotator cuff pathology

Pathology of the rotator cuff and sub-acromial bursa are considered to be the main cause of shoulder pain and dysfunction. In the absence of trauma, conservative care, including physiotherapy is the primary treatment. This paper aims to present the key features of a physiotherapy assessment, excluding diagnostic tests for rotator cuff pathology. It describes and explores how assessment can be used to direct management options and develop a treatment plan.

Morphological Characteristics of the Repaired Labrum According to Glenoid Location and Its Clinical Relevance After Arthroscopic Bankart Repair: Postoperative Evaluation With Computed Tomography Arthrography

BACKGROUND

There have been no studies on the postoperative morphological characteristics of the restored labrum at different glenoid locations and its clinical relevance after arthroscopic Bankart repair with suture anchors.

PURPOSE

To analyze the morphological characteristics of the restored labrum at different locations of the glenoid and their relevance to clinical outcomes as well as affecting factors and to trace the inserted suture anchors after arthroscopic Bankart repair using computed tomography arthrography (CTA).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 46 patients (mean age, 26.5 ± 6.8 years) who underwent arthroscopic Bankart repair with absorbable suture anchors were enrolled in this study. Patients underwent CTA preoperatively and 6 months postoperatively as well as functional outcome evaluation preoperatively and at the last follow-up (>24 months) with the Rowe score and visual analog scale for pain. Labral height and width were measured on conventional axial CTA images at the 3-, 4-, and 5-o'clock positions twice by 2 raters. The postoperative measurements were also compared with those of the healthy anterior labrum, acquired from the same CTA examination of 32 consecutive patients (mean age, 26.5 ± 8.5 years) with superior labral lesions in the same study period. The postoperative difference in the measurements and between clock positions, and the relationship between the measurements and the clinical factors and functional outcomes, were evaluated. In addition, the locations of all suture anchors were traced on each CTA image, and outcomes according to the locations of the most inferior suture anchors were assessed.

RESULTS

The interobserver and intraobserver reliabilities of measurements at each location were excellent (Pearson correlation coefficient = 0.773-0.988). Of the 46 patients, 2 (4.35%) had redislocations after surgery. Postoperative labral height and width were significantly increased at all locations (all P < .001) up to a level similar to the healthy anterior labrum, with significantly larger values at the inferior location compared with the superior location (all P < .05). Patients who had a greater frequency of dislocations before surgery showed a lower postoperative labral height at the 5-o'clock position (P = .012), and this correlated with postoperative instability and poor functional outcomes by the Rowe score (P = .036). In most patients (41/46; 89.1%), the tips of the lowest suture anchors perforated the far cortex, and these anchors were mostly located below the 5-o'clock position (32/41; 78.0%). However, perforation of the far cortex did not affect functional outcomes.

CONCLUSION

Surgeons should be cautious of restoring labral height at the inferior glenoid location for successful arthroscopic Bankart repair. In addition, attention should be given to inserting the lowest suture anchor regardless of clinical significance.

Shoulder pain among high-level volleyball players and preseason features

PURPOSE

The main goal of this prospective study was to identify the most significant intrinsic risk factors for shoulder pain by measuring strength developed by shoulder rotators and by carrying out various morphostatic assessments.

METHODS

Sixty-six players (mean ± SD age = 24 ± 5 yr) were recruited from nine volleyball teams from the first and second divisions (34 men and 32 women) to participate in the study. Before the start of the volleyball season, all the participants completed a preseason questionnaire and underwent both a bilateral isokinetic evaluation of the shoulders and morphostatic measurements. During the subsequent 6 months of the competition period, the players reported through a weekly questionnaire any shoulder pain experienced.

RESULTS

During the ongoing season, 23% (15 of 66 players) of the volleyball players experienced dominant shoulder pain. Interestingly, participants who reported a history of dominant shoulder pain were found to have nine times higher risk of suffering further pain in their dominant shoulder. The eccentric maximal strength developed by the internal and external rotators was found to represent a protective factor in the volleyball players (respective odds ratios = 0.946, P = 0.01 and 0.94, P = 0.05). No risk factors were found among the shoulder morphostatic measurements.

CONCLUSION

In our study, the evaluation of shoulder rotator muscle strength through isokinetic assessment, especially eccentric mode, appeared to be the most contributing parameter to identify risk factors for shoulder pain. This evaluation should allow to better identify players at risk.

Measurement properties of existing clinical assessment methods evaluating scapular positioning and function. A systematic review

The aims were to compile a schematic overview of clinical scapular assessment methods and critically appraise the methodological quality of the involved studies. A systematic, computer-assisted literature search using Medline, CINAHL, SportDiscus and EMBASE was performed from inception to October 2013. Reference lists in articles were also screened for publications. From 50 articles, 54 method names were identified and categorized into three groups: (1) Static positioning assessment (n = 19); (2) Semi-dynamic (n = 13); and (3) Dynamic functional assessment (n = 22). Fifteen studies were excluded for evaluation due to no/few clinimetric results, leaving 35 studies for evaluation. Graded according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN checklist), the methodological quality in the reliability and validity domains was "fair" (57%) to "poor" (43%), with only one study rated as "good". The reliability domain was most often investigated. Few of the assessment methods in the included studies that had "fair" or "good" measurement property ratings demonstrated acceptable results for both reliability and validity. We found a substantially larger number of clinical scapular assessment methods than previously reported. Using the COSMIN checklist the methodological quality of the included measurement properties in the reliability and validity domains were in general "fair" to "poor". None were examined for all three domains: (1) reliability; (2) validity; and (3) responsiveness. Observational evaluation systems and assessment of scapular upward rotation seem suitably evidence-based for clinical use. Future studies should test and improve the clinimetric properties, and especially diagnostic accuracy and responsiveness, to increase utility for clinical practice.

Modifying a shrug exercise can facilitate the upward rotator muscles of the scapula

BACKGROUND

Scapular dyskinesis, characterised by drooping scapulae and reduced upward rotation, has been implicated in the presentation of a number of shoulder disorders. Traditionally, in shoulder rehabilitation programmes, the shrug exercise has been prescribed to facilitate upward rotation of the scapula by strengthening the upper trapezius muscle. The aim of this research was to compare muscle activation levels during the standard shrug and the upward rotation shrug in a normal and pathological population.

METHODS

Surface electrodes recorded electromyographical activity from upper trapezius, middle trapezius, lower trapezius and serratus anterior muscles in 23 normal participants and 14 participants with multi-directional shoulder instability. Participants completed 10 trials of the standard shrug exercise at 0° of shoulder abduction and the upward rotation shrug exercise at 30° of shoulder abduction in the coronal plane. Muscle activity was expressed as a percentage of maximum voluntary isometric contraction.

FINDINGS

The four muscles tested performed at a higher intensity during the modified shrug than the standard shrug. Upper trapezius and lower trapezius activity was significantly greater (P < 0.05) in both populations. Though for middle trapezius and serratus anterior muscles, the modified shrug was statistically significant only in the normal population, P = 0.031 and P = <0.001 respectively.

INTERPRETATION

The upward rotation shrug is a more effective exercise for eliciting muscle activity of the upper and lower trapezius than the standard shrug in a normal and multi-directional instability population. Clinically, the upward rotation shrug might be useful to address scapular dyskinesis involving drooping shoulders and reduced scapula upward rotation.

Prediction bands and intervals for the scapulo-humeral coordination based on the Bootstrap and two Gaussian methods

Quantitative motion analysis protocols have been developed to assess the coordination between scapula and humerus. However, the application of these protocols to test whether a subject's scapula resting position or pattern of coordination is "normal", is precluded by the unavailability of reference prediction intervals and bands, respectively. The aim of this study was to present such references for the "ISEO" protocol, by using the non-parametric Bootstrap approach and two parametric Gaussian methods (based on Student's T and Normal distributions). One hundred and eleven asymptomatic subjects were divided into three groups based on their age (18-30, 31-50, and 51-70). For each group, "monolateral" prediction bands and intervals were computed for the scapulo-humeral patterns and the scapula resting orientation, respectively. A fourth group included the 36 subjects (42 ± 13 year-old) for whom the scapulo-humeral coordination was measured bilaterally, and "differential" prediction bands and intervals were computed, which describe right-to-left side differences. Bootstrap and Gaussian methods were compared using cross-validation analyses, by evaluating the coverage probability in comparison to a 90% target. Results showed a mean coverage for Bootstrap from 86% to 90%, compared to 67-70% for parametric bands and 87-88% for parametric intervals. Bootstrap prediction bands showed a distinctive change in amplitude and mean pattern related to age, with an increase toward scapula retraction, lateral rotation and posterior tilt. In conclusion, Bootstrap ensures an optimal coverage and should be preferred over parametric methods. Moreover, the stratification of "monolateral" prediction bands and intervals by age appears relevant for the correct classification of patients.

Scapulothoracic muscle activity and recruitment timing in patients with shoulder impingement symptoms and glenohumeral instability

BACKGROUND

Various studies have investigated scapulothoracic muscle activity and recruitment patterns in relation to shoulder complaints in different populations, but a consensus review is lacking.

HYPOTHESIS/PURPOSE

To systematically review the state of the art regarding scapulothoracic muscle activity and recruitment timing in subjects with shoulder pain compared to pain free controls.

STUDY DESIGN

Systematic review.

METHODS

The search for relevant articles was performed in Pubmed and Web of Science, including Web of Knowledge, using key words related to shoulder pain, scapulothoracic muscle activity or recruitment timing. Articles were included till November 2012. Case-control studies concerning the scapulothoracic region and muscle recruitment using electromyography (EMG) were included. Articles regarding rotator cuff muscles or neck-shoulder pathologies or studies handling a treatment outcome, were excluded. The methodological quality of the articles was assessed using appropriate risk of bias criteria for case-control studies.

RESULTS

A total of 12 articles were included in the systematic review, containing patients with Shoulder Impingement Syndrome (SIS) or glenohumeral instability. In patients with SIS 3 out of 6 articles showed increased upper trapezius muscle (UT) activity, 3 out of 5 studies showed decreased lower trapezius muscle (LT) activity and 3 out of 5 articles showed decreased serratus anterior muscle (SA) activity. Patients with glenohumeral instability showed contradictory results on scapulothoracic muscle activity patterns. In both SIS and glenohumeral instability patients, no consensus was found on muscle recruitment timing.

CONCLUSION

Patients with SIS and glenohumeral instability display numerous variations in scapulothoracic muscle activity compared to healthy controls. In the SIS-group, the LT and SA muscle activity is decreased. In addition, the UT muscle activity is increased among the SIS patients, whereas no clear change is seen among patients with glenohumeral instability. Although the scapulothoracic muscle activity changed, no consensus could be made regarding muscle recruitment timing.

Interrater reliability of clinical tests to evaluate scapulothoracic motion

Background

Decreased scapulothoracic motion has been associated with various pathologies of the shoulder. Reliable and simple assessment methods of scapular mobility are, however lacking. The aim of this study was to evaluate the interrater reliability of four clinical tests to assess scapulothoracic motion in patients with a slightly restricted shoulder flexion.

Methods

A total of nineteen patients with a symptomatic slight restriction of shoulder flexion and twenty asymptomatic subjects were evaluated. The investigation consisted of four palpatory tests to assess scapulothoracic motion. A two-level rating scale (positive, negative) was utilised. Interrater reliability was evaluated using kappa coefficients.

Results

We found substantial to almost perfect (Kappa = 0.63-0.4) interrater reliability for the four tests.

Conclusion

Our study demonstrates that the four mobility tests of the shoulder are a reliable and simple instrument to assess patients with a slightly restricted shoulder flexion. Future studies should be conducted to evaluate the validity of these tests and to establish their clinical usefulness.

The painful shoulder: shoulder impingement syndrome

Rotator cuff disorders are considered to be among the most common causes of shoulder pain and disability encountered in both primary and secondary care.

The general pathology of subacromial impingment generally relates to a chronic repetitive process in which the conjoint tendon of the rotator cuff undergoes repetitive compression and micro trauma as it passes under the coracoacromial arch. However acute traumatic injuries may also lead to this condition.

Diagnosis remains a clinical one, however advances in imaging modalities have enabled clinicians to have an increased understanding of the pathological process. Ultrasound scanning appears to be a justifiable and cost effective assessment tool following plain radiographs in the assessment of shoulder impingment, with MRI scans being reserved for more complex cases.

A period of observed conservative management including the use of NSAIDs, physiotherapy with or without the use of subacromial steroid injections is a well-established and accepted practice. However, in young patients or following any traumatic injury to the rotator cuff, surgery should be considered early. If surgery is to be performed this should be done arthroscopically and in the case of complete rotator cuff rupture the tendon should be repaired where possible.

Clinical implications of scapular dyskinesis in shoulder injury: the 2013 consensus statement from the 'Scapular Summit'

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.

Conscious correction of scapular orientation in overhead athletes performing selected shoulder rehabilitation exercises: the effect on trapezius muscle activation measured by surface electromyography

STUDY DESIGN

Controlled laboratory study.

OBJECTIVES

To assess the effect of conscious correction of scapular orientation on the activation of the 3 sections of the trapezius muscle during shoulder exercises in overhead athletes with scapular dyskinesis.

BACKGROUND

Previous research has led to the recommendation of 4 exercises for training of the trapezius muscle: prone extension, sidelying external rotation, sidelying forward flexion, and prone horizontal abduction with external rotation. However, the extent to which conscious correction of scapular orientation impacts trapezius muscle activation levels during these exercises is unknown.

METHODS

Absolute (upper trapezius [UT], middle trapezius [MT], lower trapezius [LT]) and relative (UT/MT and UT/LT) muscle activation levels were determined with surface electromyography in 30 asymptomatic overhead athletes with scapular dyskinesis, during 4 selected exercises performed with and without conscious correction of scapular orientation. Repeated-measures analyses of variance were used to determine if a voluntary scapular orientation correction strategy influenced the activation levels of the different sections of the trapezius during each exercise.

RESULTS

With conscious correction of scapular orientation, activation levels of the 3 sections of the trapezius muscle significantly increased during prone extension (mean ± SD difference: UT, 5.9% ± 8.6% maximal voluntary isometric contraction [MVIC]; MT, 13.8% ± 11.0% MVIC; LT, 9.8% ± 10.8% MVIC; P<.05) and sidelying external rotation (UT, 2.2% ± 4.4% MVIC; MT, 6.7% ± 10.6% MVIC; LT, 13.3% ± 24.4% MVIC; P<.05). There was no difference between conditions for sidelying forward flexion and prone horizontal abduction with external rotation. The UT/MT and UT/LT ratios were similar between conditions for all 4 exercises.

CONCLUSION

Conscious correction of scapular orientation during the prone extension and sidelying external rotation exercises can be used to increase the activation level in the 3 sections of the trapezius in overhead athletes with scapular dyskinesis. Although lack of kinematic data limits the interpretation of the results, this study suggests that conscious correction of scapular orientation can be performed without altering the favorable UT/MT and UT/LT ratios that have been previously reported for these exercises.