Critical and Theoretical Perspective on Scapular Stabilization: What Does It Really Mean, and Are We on the Right Track?

Strength and activity of the protractor and retractor muscles of the asymptomatic dyskinetic scapula

The role of scapular dyskinesis as a risk factor of shoulder injury has been largely discussed. However, most studies have focused on symptomatic patients and less is known on the asymptomatic dyskinetic scapula. Removing the confounding effects of the pathologies could contribute to better characterize the scapula dyskinesis. As muscle properties (strength, fatigue, nerve injury …) have been identified as causative factors of scapular dyskinesis, this study focuses specifically on characterizing the protractor and retractor muscles of the dyskinetic scapula. Thirteen asymptomatic dyskinetic volunteers were compared to eleven asymptomatic non-dyskinetic control volunteers. Muscle characteristics were evaluated in terms of maximal strength, fatigue resistance and electromyographic activity during a functional closed-chained task. The results did not identify kinematic or muscle activity significant differences between the dyskinetic and the control group even in fatigue conditions. However, the results demonstrated that protractors vs. retractors fatigue resistance ratios were imbalanced (<0.8) in the dyskinetic group and significantly lower than in the non-dyskinetic one. Our study suggests that that strength imbalances are not necessarily related to the presence of pain at the shoulder joint. These results demonstrated the importance to complete the clinical assessments of the scapula with strength evaluations even for asymptomatic sport practitioners.

Effects of scapulo-humeral training on ultrasonographic and clinical evaluations in stroke: a randomized controlled trial

BACKGROUND

After stroke, the effects of focused scapulo-humeral training with simultaneous assessment of the changes in shoulder subluxation, related muscle thicknesses and upper limb performance have not been studied in the literature.

OBJECTIVES

This study aimed to investigate the effects of an 8-week scapulo-humeral training program in addition to conventional rehabilitation on upper extremity/trunk functions, shoulder pain, and sonographic measurements of the shoulder joint and periscapular muscles.

METHODS

Thirty stroke individuals were randomly separated into two groups as Group I-scapulo-humeral training (5F/10 M) and Group II - control (5F/10 M). Conventional rehabilitation program was applied to both groups, and a scapulo-humeral training exercise protocol was added for the scapulo-humeral group. All the treatments were applied for 1 hour/day, 3 days/week, 8 weeks. Clinical evaluations were made using the Fugl Meyer Assessment-Upper Extremity(FMA-UE), Action Research Arm Test(ARAT), ABILHAND, Visual Analog Scale, and Trunk Impairment Scale(TIS). Ultrasound was used to measure serratus anterior/lower trapezius muscle thicknesses, and acromion-greater tubercule/acromio-humeral distances.

RESULTS

FMA-UE, ARAT, ABILHAND and TIS scores increased in both groups, with greater increases in most parameters in the scapulo-humeral training group. Shoulder pain decreased only in the scapulo-humeral training group. Subacromial distances were decreased on the paretic side, and muscle thicknesses increased on both sides in the scapulo-humeral training group, and in the control group, only serratus anterior muscle thickness increased on the paretic side (p < 0.05 for all).

CONCLUSIONS

Additional scapulo-humeral exercises to conventional rehabilitation was seen to improve upper extremity/trunk performance and shoulder pain, and to increase scapula stabilizer muscle thicknesses in stroke individuals with mild-moderate upper extremity disability.

The efficacy of exercise therapy for rotator cuff related shoulder pain according to the FITT principle: a systematic review with meta-analyses

OBJECTIVE: To evaluate the efficacy of exercise interventions with differing frequency, intensity, type and time (FITT) on shoulder pain and disability in people with rotator cuff related shoulder pain (RCRSP). DESIGN: Intervention systematic review with meta-analyses. LITERATURE SEARCH: Electronic searches were conducted up to May 2023. STUDY SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing the effects of exercise interventions differing in prescription according to the FITT principle, in people with RCRSP. DATA SYNTHESIS: Separate meta-analyses comparing exercise type (specific versus non-specific exercise) and intensity (high versus low) were conducted. GRADE was used to evaluate the certainty of evidence. RESULTS: Twenty-two RCTs (n=1281) were included. There was moderate certainty evidence that motor control exercise programs, when compared to non-specific exercise programs, significantly reduced disability in the short- (SMD: -0.29; 95%CI: -0.51 to -0.07; n=323; 7 RCTs) and medium-term (SMD: -0.33; 95%CI: -0.57 to -0.09; n=286; 5 RCTs), but not pain in the short-term (SMD: -0.19; 95%CI: -0.41 to 0.03; n=323; 7 RCTs). Uncertainties remained regarding other exercise types (eccentric and scapula-focused exercise programs) versus non-specific exercise programs, and exercise intensity due to low to very low certainty evidence. No trials were identified that compared different frequencies or times. CONCLUSION: For adults with RCRSP, motor control exercise programs were probably slightly superior to non-specific exercise programs. However, it is unclear if the effects were due to motor control exercise or to other program characteristics such as progression and tailoring.

Scapular motion during shoulder joint extension movement

A few reports on scapular motion during shoulder joint extension exist. Understanding the normal motion of shoulder joint extension may be useful in evaluating and treating patients with diminished or minimal shoulder joint extension. Therefore, this study aimed to identify scapular motion during shoulder joint extension movement in a sitting position. Shoulder joint extension movement in the sitting position were measured in 22 healthy adults (age, 25.8 ± 2.7 years). Shoulder joint extension, scapular upward rotation, anterior tilt, external rotation angles, and the acromion position were investigated using a three-dimensional motion analyzer. The difference from each value of 10° to 50° shoulder joint extension to each value of 0° shoulder joint extension were checked. The results were compared using multiple comparison method. In most participants, the scapula tilted posteriorly up to 30° of the shoulder joint extension and anteriorly after 30°. Scapular upward and external rotation continued to increase with shoulder extension. Furthermore, the acromion was displaced upward and backward. Thus, scapular posterior tilt is necessary for shoulder joint extension during the initial movement, followed by anterior tilt. The acromion may have been displaced posteriorly because of clavicular retraction, causing the scapula to tilt posteriorly. After 30° of shoulder joint extension, the scapular anterior tilt may have prevailed over the scapular posterior tilt.

Scapular muscle dynamic stiffness of asymptomatic subjects and subjects with chronic shoulder pain, at rest and isometric contraction conditions

Muscle stiffness had a crucial role in joint stability, particularly, at the shoulder complex. Although changes in upper trapezius muscle stiffness have been described for shoulder pain, contradictory findings have been obtained. Also, existing data regarding scapular muscles are, majorly, about trapezius. Myotonometry is a method used to assess stiffness; however, the reliability values of scapular muscle stiffness through this method have not been assessed in shoulder pain conditions. The present study aims to compare scapular muscles' stiffness (trapezius, serratus anterior, and levator scapulae) between subjects with and without chronic shoulder pain and to evaluate the related test-retest reliability. Twenty-two symptomatic and twenty-two asymptomatic subjects participated in a cross-sectional study. The dynamic muscular stiffness of scapular muscles, at rest and during an isometric contraction, was measured bilaterally with myotonometry, in two moments. The differences in bilateral averaged values between symptomatic and asymptomatic subjects and the effect of the group (group presenting pain in the dominant or non-dominant side, and asymptomatic group) and of the limb (unilateral painful or asymptomatic limb, and bilateral asymptomatic limbs) were investigated. Test-retest intra-rater reliability was determined. An effect of the group was observed at rest, for middle trapezius stiffness, and during contraction, for middle and lower trapezius stiffness. For middle trapezius, increased values were observed in the group presenting pain in non-dominant side comparing to both groups or to group presenting pain in dominant side. The intraclass correlation coefficient, majorly, ranged between 0.775 and 0.989. Participants with pain in the non-dominant side presented an increased middle trapezius' stiffness. Globally, high reliability was observed for scapular muscles dynamic stiffness.

Effects of Scapular Angular Deviations on Potential for Rotator Cuff Tendon Mechanical Compression

Background

One proposed mechanism of rotator cuff disease is scapular motion impairments contributing to rotator cuff compression and subsequent degeneration.

Purpose

To model the effects of scapular angular deviations on rotator cuff tendon proximity for subacromial and internal mechanical impingement risk during scapular plane abduction.

Study Design

Descriptive laboratory study.

Methods

Three-dimensional bone models were reconstructed from computed tomography scans obtained from 10 asymptomatic subjects and 9 symptomatic subjects with a clinical presentation of impingement syndrome. Models were rotated to average scapular orientations from a healthy dataset at higher (120°) and lower (subject-specific) humeral elevation angles to investigate internal and subacromial impingement risks, respectively. Incremental deviations in scapular upward/downward rotation, internal/external rotation, and anterior/posterior tilt were imposed on the models to simulate scapular movement impairments. The minimum distance between the rotator cuff insertions and potential impinging structures (eg, glenoid, acromion) was calculated. Two-way mixed-model analyses of variance assessed for effects of scapular deviation and group.

Results

At 120° of humerothoracic elevation, minimum distances from the supraspinatus and infraspinatus insertions to the glenoid increased with ≥5° changes in upward rotation (1.6-9.8 mm, P < .001) or external rotation (0.9-5.0 mm, P≤ .048), or with ≥10° changes in anterior tilt (1.1-3.2 mm, P < .001). At lower angles, ≥20° changes in most scapular orientations significantly increased the distance between the supraspinatus and infraspinatus insertions and the acromion or coracoacromial ligament.

Conclusion

A reduction in scapular upward rotation decreases the distance between the rotator cuff tendon insertions and glenoid at 120° humerothoracic elevation. Interpretation is complicated for lower angles because the humeral elevation angle was defined by the minimum distance.

Clinical Relevance

These results may assist clinical decision making regarding the effects of scapular movement deviations in patients with rotator cuff pathology and scapular dyskinesia and may help inform the selection of clinical interventions.

Normal values of scapular muscle activity ratio during arm elevation and the relationship to muscle strength and sex difference

BACKGROUND

The normal value of the scapular muscle activity ratio during arm elevation is not clear.

OBJECTIVE

To obtain normal values of the scapular muscle activity ratio during arm elevation in healthy individuals.

METHODS

This cross-sectional study enrolled 47 healthy people. The participants performed shoulder flexion and lowered task with 90-degree movements every 2 seconds. Muscle activities of scapular muscles were measured. For normalization, the maximum isometric contraction of the shoulder flexion was measured at 90∘ (reference contraction). The integrated electromyographic value (IEMG) obtained during the task was normalized by IEMG during the reference contraction and the relative IEMG value was calculated. Then, the scapular muscle activity ratio was computed. The relationship between muscle strength and other factors was also investigated.

RESULTS

The median values for upper trapezius/serratus anterior and upper trapezius/lower trapezius were often approximately 1, and that for upper trapezius/middle trapezius was often between 1 and 2. The shoulder flexion isometric strength and scapular muscle activity ratio showed significant negative correlations in multiple phases.

CONCLUSION

Normal values for upper trapezius/serratus anterior and upper trapezius/lower trapezius during arm elevation and lowering were generally 1. Low muscle strength may contribute to an abnormal scapular muscle activity balance.

Prevalence of positive modified scapular assistance test in patients with shoulder pain with and without scapular dyskinesis: a cross-sectional study

BACKGROUND

Scapular dyskinesis (SD) is defined as an altered position of the scapula or altered motion patterns and their relationship with shoulder pain (SP) is still under debate. The modified scapular assistance test (mSAT) modifies scapular kinematics and is used to determine the impact of scapular dyskinesis in shoulder pain. However, data about the relationship between SD and the result of mSAT is scarce.

PURPOSE

The aim of this study is to establish the frequency of positive mSAT in patients with SP and compare the prevalence in those with and without SD. As a secondary objective, we compare changes in pain intensity during the mSAT in patients with a positive test between those with and without SD.

STUDY DESIGN

Cross-sectional study.

METHODS

Adult patients with a diagnosis of SP and with pain ≥2 during anterior flexion were included. The mSAT, scapular dyskinesis test (SDT), and shoulder function were assessed.

RESULTS

The study was conducted between August 2018 and May 2022 and included 70 patients. The prevalence of SDT was 54.29%. No statistically significant associations were detected when assessing the relation between the presence of mSAT and SDT (p-value 0.83). When comparing pain response during the mSAT in patients with a positive test, no differences were seen between patients with SD and patients without SD (p-value 0.26).

CONCLUSIONS

The prevalence of positive mSAT results was equal between individuals with and without SD. These findings suggest that the presence or absence of SD in individuals with SP was independent of the mSAT result. The mSAT should not be used solely for the assessment of SD in clinical practice nor be influenced by the SDT result. More research is needed to determine if the result of this test could inform prognosis and guide treatment choices.

Is it Time to Normalize Scapular Dyskinesis? The Incidence of Scapular Dyskinesis in Those With and Without Symptoms: a Systematic Review of the Literature

Background

Up to 67% of adults experience shoulder pain in their lifetime. Numerous factors are related to the etiology of shoulder pain, one of which is thought to be scapular dyskinesis (SD). Given the prevalence of SD among the asymptomatic population a concern is that the condition is being medicalized (clinical findings suggested to require treatment but is ultimately a normal finding). Therefore, the purpose of this systematic review was to investigate the prevalence of SD among both symptomatic and asymptomatic populations.

Methods

A systematic review of the literature up to July of 2021. Relevant studies identified from PubMed, EMBASE, Cochrane and CINAHL were screened utilizing the following inclusion and exclusion criteria; inclusion: (a) individuals being assessed as having SD, including reliability and validity studies (b) subjects aged 18 or older; (c) sport and non-sport participants; (d) no date restriction; (e) symptomatic, asymptomatic, or both populations; (f) all study designs except case reports. Studies were excluded if: (a) they were not published in the English language; (b) they were a case report design; (c) the presence of SD was part of the studies inclusion criteria; (d) data were not present distinguishing the number of subjects with or without SD; (e) they did not define participants as having or not having SD. Methodological quality of the studies was assessed utilizing the Joanna Briggs Institute checklist.

Results

The search resulted in 11,619 after duplicates were removed with 34 studies ultimately retained for analysis after three were removed due to low quality. A total of 2,365 individuals were studied. Within the studies for the symptomatic athletic and general orthopedic population there were 81% and 57% individuals with SD, respectively, and a total of 60% among both symptomatic groups (sport and general orthopedic population). Within the studies for the asymptomatic athletic and general population there were 42% and 59% individuals with SD, respectively, and a total of 48% among both asymptomatic groups (sport and general orthopedic population).

Limitation

A strict inclusion and exclusion criteria was used to identify studies that provided the appropriate data for the purpose of this study. There was a lack of consistency for measuring SD across studies.

Conclusion

A considerable number of individuals with shoulder symptoms do not present with SD. More revealing is the number of asymptomatic individuals who do present with SD, suggesting that SD may be a normal finding among nearly half of the asymptomatic population.

Level of Evidence

2a.

Can specific virtual reality combined with conventional rehabilitation improve poststroke hand motor function? A randomized clinical trial

TRIAL OBJECTIVE

To verify whether conventional rehabilitation combined with specific virtual reality is more effective than conventional therapy alone in restoring hand motor function and muscle tone after stroke.

TRIAL DESIGN

This prospective single-blind randomized controlled trial compared conventional rehabilitation based on physiotherapy and occupational therapy (control group) with the combination of conventional rehabilitation and specific virtual reality technology (experimental group). Participants were allocated to these groups in a ratio of 1:1. The conventional rehabilitation therapists were blinded to the study, but neither the participants nor the therapist who applied the virtual reality-based therapy could be blinded to the intervention.

PARTICIPANTS

Forty-six patients (43 of whom completed the intervention period and follow-up evaluation) were recruited from the Neurology and Rehabilitation units of the Hospital General Universitario of Talavera de la Reina, Spain.

INTERVENTION

Each participant completed 15 treatment sessions lasting 150 min/session; the sessions took place five consecutive days/week over the course of three weeks. The experimental group received conventional upper-limb strength and motor training (100 min/session) combined with specific virtual reality technology devices (50 min/session); the control group received only conventional training (150 min/session).

RESULTS

As measured by the Ashworth Scale, a decrease in wrist muscle tone was observed in both groups (control and experimental), with a notably larger decrease in the experimental group (baseline mean/postintervention mean: 1.22/0.39; difference between baseline and follow-up: 0.78; 95% confidence interval: 0.38-1.18; effect size = 0.206). Fugl-Meyer Assessment scores were observed to increase in both groups, with a notably larger increase in the experimental group (total motor function: effect size = 0.300; mean: - 35.5; 95% confidence interval: - 38.9 to - 32.0; wrist: effect size = 0.290; mean: - 5.6; 95% confidence interval: - 6.4 to - 4.8; hand: effect size = 0.299; mean: - -8.9; 95% confidence interval: - 10.1 to - 7.6). On the Action Research Arm Test, the experimental group quadrupled its score after the combined intervention (effect size = 0.321; mean: - 32.8; 95% confidence interval: - 40.1 to - 25.5).

CONCLUSION

The outcomes of the study suggest that conventional rehabilitation combined with a specific virtual reality technology system can be more effective than conventional programs alone in improving hand motor function and voluntary movement and in normalizing muscle tone in subacute stroke patients. With combined treatment, hand and wrist functionality and motion increase; resistance to movement (spasticity) decreases and remains at a reduced level.

TRIALS REGISTRY

International Clinical Trials Registry Platform: ISRCTN27760662 (15/06/2020; retrospectively registered).

Prevalence of scapular dyskinesis in office workers with neck and scapular pain

Objectives. This study aimed to investigate the presence of scapular dyskinesis (SD) in office workers with neck and scapular complaints. The postural malalignment and related muscle adaptations were also explored. Methods. SD and its subtypes were determined. Postural deviations and the length of commonly reported muscle tightness were evaluated. Results. Among 99 participants, 90% of them had SD. Considering both sides or 198 scapula, 90.4% were identified as having painful scapula and 19% as having painless scapula. There was a difference in the proportion of SD on painful (93%) and painless (69%) sides. Postural deviations including rounded shoulder (100%), forward head (43.3%) and thoracic hyperkyphosis (54.5%) were prevalent. Persons with type III SD had a higher percentage of forward head than other types. There was also tightness of the pectoralis minor (100%), levator scapulae (93.0%) and upper trapezius (98.3%) muscles without different proportions among types of SD. The greatest proportion of persons with SD had tightness of the levator scapulae. Conclusions. There was a high prevalence of SD among office workers with neck and scapular complaints. SD was also associated with abnormal posture and muscle tightness. The proper management of SD and working posture is warranted.

Pitching Biomechanics and Shoulder Function in Baseball Pitchers with Scapular Dyskinesis

The primary purpose was to investigate the influence of scapular dyskinesis (SD) on pitching biomechanics and shoulder function in high school baseball pitchers. The secondary purpose was to identify possible factors associated with shoulder function in pitchers with SD. Thirty-eight pitchers were classified into the SD group (n=26) or the non-SD group (n=12). They were evaluated with the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) scale and clinical measurements of shoulder characteristics, and with measurements of scapular kinematics, muscle activation, and ball speed during fastball pitching. Compared to the controls, the pitchers with SD had less scapular external rotation (difference=11.3 degrees, ES=0.92, p=0.012) during overall pitching and less upper trapezius (UT) activation during the late cocking (difference=7.1%, ES=0.79, p=0.019) and acceleration phases (difference=12.5%, ES=0.75, p=0.035). Higher UT activation during the late cocking phase was significantly associated with higher KJOC scores (standardized β=0.415, p=0.039). In conclusion, deficits in scapular external rotation and decreased UT activation during pitching were found in pitchers with SD. Higher UT activation may be important for shoulder function in pitchers with SD.

The influence of shoulder position during multi-joint exercises in the relative scapular muscles activity in symptomatic and asymptomatic conditions

BACKGROUND

Scapular muscles changes, as increased upper trapezius activity and decreased middle and lower trapezius and serratus anterior muscle activity, have been demonstrated in shoulder pain specific or non-specific conditions. Shoulder external rotation exercises have been recommended to improve scapular activity in shoulder pain.

OBJECTIVE

To evaluate the relative scapular muscles activity during multi-joint exercises combining shoulder external rotation, trunk rotation and scapular squeeze.

METHODS

Forty-one participants with and without shoulder pain were assessed in a cross-sectional study. They performed isometric multi-joint exercises at 0∘ and 90∘ of shoulder abduction with and without support. The relative activity of upper, middle, and lower trapezius and serratus anterior (upper/middle and lower portions) was measured through electromyography. The scapular muscular balance was assessed by the ratio between relative activity of the upper trapezius and the other muscles.

The short-term effectiveness of scapular focused taping on scapular movement in tennis players with shoulder pain: A within-subject comparison

This study aimed to investigate the short-term effectiveness of scapular focused taping (SFT) on scapular position and kinematics during the tennis serve among professional players with and without shoulder pain. The cohort included 7 players who had no history of non-shoulder pain (NSP) and 6 players with shoulder pain (SP). All participants performed tennis flat serves while the Qualisys motion capture system recorded three-dimensional scapular kinematic data according to the International Society of Biomechanics recommendations. SFT was applied to the participants' torso aligned with the lower trapezius, and the same movements were repeated. In the SP group, the scapula was tilted more posteriorly after the application of SFT as compared to before at ball release and maximally externally rotated humerothoracic joint during tennis serve (t = -5.081, P = .004 and t = -2.623, P = .047, respectively). In the NSP group, the scapula was tilted more posteriorly with SFT as compared to without at first 75% timing of the cocking phase and maximally externally rotated humerothoracic joint (t = -3.733, P = .010 and t = -2.510, P = .046, respectively). And the SP group exhibited a more rotated scapula externally after the application of SFT as compared to before at Ball impact (t = 5.283, P = .003). SFT had a positive immediate effect on the scapular posterior tilting and external rotation during certain phases of the tennis serve among tennis athletes with and without shoulder pain. These findings may help clinicians and sports practitioners to prevent and rehabilitate shoulder injuries for overhead athletes. Level of evidence: Level III; Case-Control Design; Comparative Study.

Clavicular and scapular, but not spinal kinematics vary with scapular dyskinesis type during arm elevation and lowering in persons with neck pain

BACKGROUND

Scapular dyskinesis is often observed in patients with neck pain. However, it is unknown whether clavicular, scapular and spinal kinematics vary with different types of scapular dyskinesis during arm movement.

RESEARCH QUESTION

Are there differences in clavicular, scapular and spinal kinematics during unilateral arm elevation and lowering among neck pain patients presenting with (i) scapular winging, (ii) with dysrhythmia, (iii) with no scapular abnormality and (iv) healthy controls?

METHODS

Sixty participants with neck pain (20 in each group) and 20 asymptomatic controls were recruited. The 3D kinematic data were measured during unilateral arm elevation and lowering at 30°, 60°, 90°, and 120° in the scapular plane. A three-way mixed-effects ANOVA was used to determine the main effects (group, phase and angle) and the interactions between three independent variables on the kinematic data.

RESULTS

The neck pain group with scapular winging had decreased clavicular retraction and increased scapular internal rotation and anterior tilt compared to the other neck pain and control groups at all angles during both phases of arm movement (p < 0.01). The neck pain group with scapular dysrhythmia had decreased scapular upward rotation compared to all other groups (p < 0.01). Some alterations in the kinematics existed during the lowering phase compared to the raising phase for all groups (p < 0.05). Spinal kinematics were similar across all groups (p > 0.05).

SIGNIFICANCE

Specific patterns of clavicular and scapular kinematics were identified during arm movement relevant to the type of observed scapular dyskinesis in patients with neck pain. Such findings stand to inform more precise and relevant motor training in rehabilitation and improve understanding of the association between altered scapular kinematics and neck pain.

Association between changes in pain or function scores and changes in scapular rotations in patients with subacromial shoulder pain: a prospective cohort study

Background

Scapular dyskinesis is reported as one of the potential factors contributing to the presentation of pain in subacromial shoulder pain. In clinical practice, the evaluation and control of scapular dyskinesis is considered important for managing the subacromial shoulder pain. The aim is to determine the association between changes in pain or function and changes in scapular rotations in participants with subacromial shoulder pain.

Method

Pain, function and scapular rotations were measured in 25 participants with subacromial shoulder pain at baseline and after 8 weeks. Pain was measured with Numeric Pain Rating Scale (NPRS) and function was measured with Patient Specific Functional Scale (PSFS). Scapular rotations were measured with a scapular locator at 60°, 90° and 120° of scapular arm elevation. Spearman rank correlations (r_s) were used to assess the association between variables.

Findings

No association was observed between changes in pain or function scores with changes in scapular upward/downward rotations (r_s = 0.03 to 0.27 for pain and − 0.13 to 0.23 for function) and scapular anterior/posterior tilt (r_s = − 0.01 to 0.23 for pain and − 0.13 to 0.08 for function) of arm at 60°, 90° and 120° elevation. Data associated with scapular internal/external rotation was not reported due to low reliability.

Conclusion

These findings reject associations between changes in pain or function scores and scapular rotations. Future observational study is warranted using a multifactorial approach to understand potential factors that contribute to the presentation of subacromial shoulder pain.

Causal mechanisms of a scapular stabilization intervention for patients with subacromial pain syndrome: a secondary analysis of a randomized controlled trial

Background

Causal mediation analysis is one way to bridge this gap by exploring the causal pathways of a given intervention. The aim of this study was to assess whether scapular motion, position, and periscapular muscle strength are mediators for pain and shoulder disability outcomes following a scapular stabilization intervention for patients with subacromial pain syndrome.

Methods

Sixty patients were randomized into two groups: scapular stabilization or periscapular strengthening exercises. The intervention consisted of three sessions per week for 8 weeks. The primary outcome measures were pain and disability and the following outcome measures were considered as potential mediators: scapular motion, scapular position, periscapular muscle strength, age, duration of symptoms, and side of the complaint. A model-based inference approach with bootstrap simulations was used to estimate the average causal mediation effect, average direct effect, and the average total effect from the data of a randomized clinical trial that evaluated the effect of adding scapular stabilization exercises to a scapulothoracic strengthening program in people with subacromial pain syndrome.

Results

The results demonstrated that none of the putative mediators were influenced by the intervention. However, muscle strength of serratus anterior, upper, middle, and lower trapezius muscles was associated with shoulder disability.

Conclusion

Scapular kinematic and periscapular muscle strength did not mediate the effect of scapular stabilization exercises on shoulder pain or disability scores in subjects with subacromial pain syndrome. Muscle strength of serratus anterior, upper, middle and lower trapezius were associated with shoulder disability scores at 8-weeks follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40945-022-00138-1.

Comparing exercises with and without electromyographic biofeedback in subacromial pain syndrome: A randomized controlled trial

BACKGROUND

Deficits in movement and muscle activation of scapulohumeral joint are related to Subacromial Pain Syndrome. Electromyography biofeedback during exercise may enhance muscle activation and coordination, and consequently improve pain and shoulder function.

METHODS

This study compared the effects of an exercise protocol with and without using electromyographic biofeedback on pain, function and movement of the shoulder complex in subjects with Subacromial Pain Syndrome. A total of 24 patients with subacromial pain (mean age = 46.2 + 8.1;18 women) were randomized to either therapeutic exercise or exercise plus biofeedback to the trapezius and serratus muscles. Pain and shoulder function were evaluated as the primary outcome and range of motion, muscle strength, electromyographic activity and scapulohumeral kinematics as secondary outcomes. The subjects underwent eight weeks of intervention and comparisons were made between groups in baseline, at 4 weeks, 8 weeks, and at 4 weeks post intervention.

FINDINGS

There were differences between groups for pain [mean difference = 1.5 (CI 0.3, 3.2) p = 0.01] at 8 weeks in the Exercise group and scapular upward rotation at 60° of arm elevation [mean difference = 13.9 (CI 0.9, 9.3), p = 0.006] in the Biofeedback group. There was no difference for the other variables of scapular kinematics as well as for shoulder function (DASH), muscle strength, range of motion and electromyographic variables.

INTERPRETATION

The addition of Biofeedback to the exercise protocol increased upward rotation of the scapula. However, the volunteers who performed only the Exercises had a better response in reducing pain.

Shoulder pain across more movements is not related to more rotator cuff tendon findings in people with chronic shoulder pain diagnosed with subacromial pain syndrome

Supplemental Digital Content is Available in the Text. Neither the number nor severity of rotator cuff tendons reported as abnormal was associated with the pain occurrence across clinically relevant arm movements.

Introduction:

People with chronic shoulder pain commonly report pain during arm movements in daily-life activities. Pain related to movement is commonly viewed as an accurate representation of tissue damage. Thus, when a person reports pain across a variety of movements, this is often understood as indicative of greater damage.

Objectives:

We aimed to investigate if movement-related pain that occurs across a wider variety of movements was associated with the number or severity of rotator cuff tendons reported as abnormal on a magnetic resonance imaging (MRI). To answer this question, this study was designed in 3 phases.

Methods:

We recruited 130 individuals with chronic shoulder pain diagnosed with subacromial pain syndrome. First, a list of daily functional activities commonly reported as painful by people with chronic shoulder pain was generated from 3 well-established outcome measures with 30 individuals and a measurement tool was developed with data from further 100 individuals, which demonstrated to have acceptable content validity, construct validity, internal consistency, interrater reliability, and structural validity. Multiple linear regression was then used to evaluate the hypotheses of the study. A direct acyclic graph was used to select variables for linear regression modelling.

Results:

There was no association between movement-related pain occurrence across movements and the MRI findings.

Conclusion:

Our study provides evidence that neither the number of rotator cuff tendons reported as abnormal nor the severity of each tendon imaging finding were associated with pain occurrence across movements and activities commonly perceived as painful by people with chronic shoulder pain.

Scapular stabilization exercise based on the type of scapular dyskinesis versus traditional rehabilitation training in the treatment of periarthritis of the shoulder: study protocol for a randomized controlled trial

Background

Periarthritis of the shoulder is a common disease leading to dysfunction of the shoulder joint and have a significant impact on patients’ daily life. Evidence shows that there is a close relationship between scapular dyskinesis (SD) and shoulder diseases. Scapular stabilization exercise has been proved to be efficacious in relieving pain and improving function. However, there is no targeted exercise based on the type of scapular dyskinesis. This study will investigate the potential of scapular stabilization exercise based on the type of scapular dyskinesis in treating periarthritis of the shoulder.

Methods

This study is a prospective, randomized controlled, parallel-group trial, intending to recruit 90 patients diagnosed with periarthritis of the shoulder. Patients will receive scapular stabilization exercise training based on the type of scapular dyskinesis or receive traditional rehabilitation training conducted for 30 min, once a day, for 6 weeks. The primary outcome is Constant-Murley score (CMS), and other outcomes include pain degree, range of motion (ROM), type of scapular dyskinesis, scapula position, and patients’ satisfaction with shoulder function. Assessments will be performed at baseline, 2-, 4- and 6-week treatment, and at the 6-week follow-up after the end of treatment.

Discussion

This study will be the first study to investigate the clinical efficacy of scapular stabilization exercise based on the type of scapular dyskinesis in patients with periarthritis of the shoulder. The results may provide evidence of the effect of targeted scapular stabilization exercise in improving shoulder function and correcting scapular dyskinesis, and provide valuable information for future research.

Trial registration

This study had been registered in the Chinese Clinical Trials Registry. Registration number: ChiCTR2100044332 at March 14, 2021.

Does scapular corrective taping alter periscapular muscle activity and 3-dimensional scapular kinematics? A systematic review

STUDY DESIGN

This is a systematic review.

INTRODUCTION

Scapular taping is widely used in the management of scapular dysfunction. However, its effects on the scapular kinematics and the electromyography (EMG) activity of the periscapular muscles are not clear.

PURPOSE OF THE STUDY

The purpose of the study was to systematically review the current literature to examine whether scapular corrective taping alters the EMG activity of the periscapular muscles and the 3-dimensional scapular kinematics.

METHOD

MEDLINE and Web of Science databases were searched using specific mesh terms up to April 2018. A hand search was also conducted on the reference list of the included articles. A total of 157 studies were identified, and they were further analyzed for the eligibility to the systematic review. Studies that investigated the effects of scapular corrective taping on the EMG activity of the periscapular muscles and on the 3-dimensional scapular kinematics on patients with shoulder problems or asymptomatic subjects were eligible for the systematic review. The Cochrane Effective Practice and Organization of Care criteria were modified and used for the risk-of-bias assessment.

RESULTS

Eleven articles met the inclusion criteria and were included in the systematic review. Five studies investigated the effects of corrective taping on the scapular kinematics and 8 studies reported the effects of corrective taping on the EMG activity of the periscapular muscles. There was an agreement among the studies that scapular upward rotation is increased with the corrective taping, while there are inconsistent results concerning the scapular external rotation and posterior tilt. In addition, studies mostly reported that corrective taping decreases the activity of the upper trapezius, while it has conflicting effects on the activity patterns of other periscapular muscles.

DISCUSSION

Scapular corrective taping was found to increase the scapular upward rotation; however, its effects on scapular external rotation and posterior tilt are controversial. It was also found that corrective taping might decrease the EMG activity of the upper trapezius, while it had no effects on the activity of lower trapezius, and its effects on other periscapular muscles were controversial.

CONCLUSION

The results of the studies indicated that scapular corrective taping might alter the 3-dimensional scapular kinematics, while there are controversies about the effects of corrective taping on the EMG activity of the periscapular muscles. Further studies are needed to clarify the conflicts.

Stepwise increase of upper limb muscle activity induced by progressive 4 positions of a handstand training

BACKGROUND: Handstand is the most important fundamental skill in gymnastics. A gradual and well-balanced increase in muscle loading in a manner is preferred for young beginners and/or recovering gymnasts to safely achieve the muscle strength required to perform a stable handstand. OBJECTIVE: To examine upper limb muscle activity during different levels of handstand training positions. METHODS: This study utilized four different positions for progressive handstand training; namely, the 90, 135, elbow stand, and handstand positions. The activities of eight upper limb muscles (upper, middle, and lower trapezius; serratus anterior; anterior and middle deltoid; infraspinatus; and latissimus dorsi were measured by surface electromyography (EMG) for each position. The percentages of EMG in each muscle compared to the values during maximum voluntary contraction were calculated and compared between the positions. RESULTS: Muscle activity around the shoulder increased gradually throughout the progression of the four handstand training positions. Furthermore, the muscles required for scapular stabilization, such as the upper and middle trapezius and serratus anterior muscles, were activated at levels similar to those for a handstand without performing this movement. CONCLUSIONS: A progressive handstand training program of four different positions resulted in gradual and well-balanced increases in muscle activity.

Scapular Dyskinesis Is Not an Isolated Risk Factor for Shoulder Injury in Athletes: A Systematic Review and Meta-analysis

BACKGROUND

Scapular dyskinesis has been considered a risk factor for athletic shoulder injury; however, findings in the prospective literature have demonstrated mixed results.

PURPOSE

To determine if scapular dyskinesis increases the risk of shoulder injury in athletes.

STUDY DESIGN

Meta-analysis.

METHODS

A systematic search was conducted on the MEDLINE, CINAHL Plus, SPORTDiscus, and Embase databases to identify prospective studies examining scapular dyskinesis and shoulder injury risk in athletes. Studies were included if they assessed participants using a dynamic scapular assessment at baseline and monitored for the development of shoulder injury. Data from the studies were subject to meta-analysis using the Mantel-Haenszel method to produce a pooled risk ratio.

RESULTS

Seven studies were eligible for inclusion, resulting in 212 shoulder injuries observed across 923 athletes. Scapular dyskinesis was present in 46% of participants, and these athletes had an injury rate of 25%. The presence of scapular dyskinesis displayed a trend to increase the risk of shoulder injury, but this was not statistically significant (risk ratio, 1.07; 95% CI, 0.85-1.34; P = .59).

CONCLUSION

Scapular dyskinesis was not significantly associated with the development of shoulder injury in athletes.

REGISTRATION

CRD42019133089 (PROSPERO).

A Comparison of Resting Scapular Posture and the Davies Closed Kinetic Chain Upper Extremity Stability Test

BACKGROUND

In orthopaedic practice, it is well established that weak scapular stabilizers and an unstable scapula is related to shoulder dysfunction. Faulty scapular position has been linked to decreased scapular stability and is thought to be a result of weak or unbalanced timing in the recruitment of scapulothoracic dynamic stabilizing muscles. Kibler has described a four-type classification of scapulothoracic dysfunction. Functional performance testing is used to objectively measure activities that simulate various desired activities. The reliability of assessing the four static scapular positions may be important in diagnosing shoulder dysfunction. An understanding of the scapular position and its relationship to functional performance testing is needed.

PURPOSE

The purpose of this study was to determine if a static scapular test, the Kibler scapula classification, in healthy participants affects the ability to perform a closed chain functional test that involves the use of the scapula and the upper extremity, the Davies Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST). A secondary analysis was performed to evaluate the reliability of a student physical therapist and an experienced physical therapist to identify scapular type by observation.

STUDY DESIGN

Multicenter, single session descriptive cohort.

METHODS

Sixty-one healthy participants (33 males, 28 females; mean age 24.19±2.61) completed testing across two locations in one testing session. Blood pressure and heart rate as well as height and weight were measured for each participant. Participants were classified by visual observation of Kibler scapular classification. The average number of CKUEST touches, a normalized score, and a power score were calculated for each participant. Three trials were performed and participants were required to take a 45-second rest break between each CKCUEST trial.

RESULTS

One way analysis of variance (ANOVA) showed statistically significant differences in Type I and Type IV Kibler scapula classification for the CKCUEST power score, however when an ANCOVA controlled for body mass index, there was no statistically significant difference. A strong correlation r=.94 was observed between student and experienced physical therapist in evaluating all four types of Kibler scapular classification.

CONCLUSIONS

Visually observed Kibler scapular position does not affect the ability to perform the Davies CKCUEST in healthy young adults. The ability to identify Kibler scapular position was reliable between student and experienced physical therapists. Additional studies are required to identify the usefulness of the Kibler scapular position classification.

LEVEL OF EVIDENCE

2b: Individual Cohort Study.

Assessment of Upper-Extremity Joint Angles Using Harmony Exoskeleton

The biomechanical complexity of the human shoulder, while critical for functionality, poses a challenge for objective assessment during sensorimotor rehabilitation. With built-in sensing capabilities, robotic exoskeletons have the potential to serve as tools for both intervention and assessment. The bilateral upper-extremity Harmony exoskeleton is capable of full shoulder articulation, forearm flexion-extension, and wrist pronation-supination motions. The goal of this paper is to characterize Harmony's anatomical joint angle tracking accuracy towards its use as an assessment tool. We evaluated the agreement between anatomical joint angles estimated from the robot's sensor data and optical motion capture markers attached to the human user. In 9 healthy participants we examined 6 upper-extremity joint angles, including shoulder girdle angles, across 4 different motions, varying active/passive motion of the user and physical constraint of the trunk. We observed mostly good to excellent levels of agreement between measurement systems with for shoulder and distal joints, magnitudes of average discrepancies varying from 0.43° to 16.03° and width of LoAs ranging between 9.44° and 41.91°. Slopes were between 1.03 and 1.43 with r > 0.9 for shoulder and distal joints. Regression analysis suggested that discrepancies observed between measured robot and human motions were primarily due to relative motion associated with soft tissue deformation. The results suggest that the Harmony exoskeleton is capable of providing accurate measurements of arm and shoulder joint kinematics. These findings may lead to robot-assisted assessment and intervention of one of the most complex joint structures in the human body.

Can the Use of Unstable Surfaces and Instruction for Conscious Abdominal Contraction Increase the EMG Activity of the Periscapular Muscles During the Dynamic Push-Up?

CONTEXT

It is believed that conscious abdominal contraction (CAC) during exercise encourages greater periscapular activation through existing myofascial connections. On the other hand, it is postulated that the use of unstable surfaces would promote greater neuromuscular demand.

OBJECTIVE

To analyze the effect of CAC on periscapular muscle activity during push-up plus exercise on stable and unstable surfaces and to evaluate the correlation between electromyographic (EMG) activity of the serratus anterior (SA) and abdominal oblique muscles.

DESIGN

Repeated-measures design in a single group, pre-post CAC.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Twenty-three male volunteers without a history of lesions in the upper limbs participated in the study.

MAIN OUTCOME MEASURES

Five repetitions of push-ups on stable and unstable surfaces were performed with and without instruction for CAC. The normalized amplitude of the EMG activity was obtained from the muscles of the upper, middle, and lower trapezius, SA upper (SA_5th) and lower (SA_7th) portions, external oblique (EO), and internal oblique.

RESULTS

CAC increased the activity of the EO, internal oblique, middle trapezius, and SA (P < .05) in both surfaces. The use of the unstable surface increased the EMG activity of the EO, SA_7th, and middle trapezius and decreased the EMG activity of the SA_5th. However, all changes observed in EMG signals were of low magnitude, with effect sizes lower than 0.45. There was a weak correlation between the EMG activity of the EO and SA_5th (r = .24) and a strong correlation between the EO and SA_7th (r = .70).

CONCLUSION

The isolated use of CAC or unstable surface during push-up seems to present no practical relevance, but the combined use of these strategies may increase activation of the SA_7th and middle trapezius muscles.

Awake Proning as an Adjunctive Therapy for Refractory Hypoxemia in Non-Intubated Patients with COVID-19 Acute Respiratory Failure: Guidance from an International Group of Healthcare Workers

Non-intubated patients with acute respiratory failure due to COVID-19 could benefit from awake proning. Awake proning is an attractive intervention in settings with limited resources, as it comes with no additional costs. However, awake proning remains poorly used probably because of unfamiliarity and uncertainties regarding potential benefits and practical application. To summarize evidence for benefit and to develop a set of pragmatic recommendations for awake proning in patients with COVID-19 pneumonia, focusing on settings where resources are limited, international healthcare professionals from high and low- and middle-income countries (LMICs) with known expertise in awake proning were invited to contribute expert advice. A growing number of observational studies describe the effects of awake proning in patients with COVID-19 pneumonia in whom hypoxemia is refractory to simple measures of supplementary oxygen. Awake proning improves oxygenation in most patients, usually within minutes, and reduces dyspnea and work of breathing. The effects are maintained for up to 1 hour after turning back to supine, and mostly disappear after 6-12 hours. In available studies, awake proning was not associated with a reduction in the rate of intubation for invasive ventilation. Awake proning comes with little complications if properly implemented and monitored. Pragmatic recommendations including indications and contraindications were formulated and adjusted for resource-limited settings. Awake proning, an adjunctive treatment for hypoxemia refractory to supplemental oxygen, seems safe in non-intubated patients with COVID-19 acute respiratory failure. We provide pragmatic recommendations including indications and contraindications for the use of awake proning in LMICs.

Effect of conscious abdominal contraction on the activation of periscapular muscles in individuals with subacromial pain syndrome

BACKGROUND

Synergism between shoulder and trunk muscles seems to be effective to increase periscapular muscle activation in asymptomatic subjects. The influence of conscious contraction of the abdominal muscles has not yet been studied in non-athlete subjects with pain. The study aimed to investigate the effect of the instruction for conscious activation of the abdominal muscles on the activity of the scapulothoracic muscles during shoulder exercises in subjects with subacromial pain syndrome.

METHOD

Thirty subjects with unilateral pain (mean age 52 ± 11 years) participated in this study. Three isometric and five dynamic exercises for the scapulothoracic muscles were assessed. The group without instruction just repeated the exercises, while the instruction group was evaluated before and after conscious abdominal training. The linear mixed model analysis was used to compare the muscle activation between groups.

FINDINGS

Differences between groups after the conscious abdominal contraction for activation of middle and lower trapezius on the symptomatic side in the "Full can"(p = 0.03; effect size:0.92 middle trapezius); (p = 0.02; effect size:0.96 lower trapezius) and "Knee Push" (p = 0.01; effect size:0.75 lower trapezius). For asymptomatic side, the exercises "External Rotation Kneeling" (p = 0.04; effect size: 0.81 lower trapezius); (p = 0.00; effect size: 2.09 serratus anterior), "Knee Push" (p = 0.04; effect size:1.24 serratus anterior) and "Wall Slide" (p = 0.01; effect size: 1.03 serratus anterior).

INTERPRETATION

Conscious contraction of the abdominal muscle immediately alter the activation of the serratus anterior muscle during closed kinetic chain exercises on the asymptomatic side and increased activation of trapezius on the symptomatic side during shoulder open kinetic chain exercise.

Arm-Hand Boost Therapy During Inpatient Stroke Rehabilitation: A Pilot Randomized Controlled Trial

Objective: It was the aim to assess feasibility, safety, and potential efficacy of a new intensive, focused arm-hand BOOST program and to investigate whether there is a difference between early vs. late delivery of the program in the sub-acute phase post stroke. Methods: In this pilot RCT, patients with stroke were randomized to the immediate group (IG): 4 weeks (4 w) BOOST +4 w CONTROL or the delayed group (DG): 4 w CONTROL +4 w BOOST, on top of their usual inpatient care program. The focused arm-hand BOOST program (1 h/day, 5x/week, 4 weeks) consisted of group exercises with focus on scapula-setting, core-stability, manipulation and complex ADL tasks. Additionally, 1 h per week the Armeo®Power (Hocoma AG, Switzerland) was used. The CONTROL intervention comprised a dose-matched program (24 one-hour sessions in 4 w) of lower limb strengthening exercises and general reconditioning. At baseline, after 4 and 8 weeks of training, the Fugl-Meyer assessment upper extremity (FMA-UE), action research arm test (ARAT), and stroke upper limb capacity scale (SULCS) were administered. Results: Eighteen participants (IG: n = 10, DG: n = 8) were included, with a median (IQR) time post stroke of 8.6 weeks (5-12). No adverse events were experienced. After 4 weeks of training, significant between-group differences were found for FMA-UE (p = 0.003) and SULCS (p = 0.033) and a trend for ARAT (p = 0.075) with median (IQR) change scores for the IG of 9 (7-16), 2 (1-3), and 12.5 (1-18), respectively, and for the DG of 0.5 (-3 to 3), 1 (0-1), and 1.5 (-1 to 9), respectively. In the IG, 80% of patients improved beyond the minimal clinical important difference of FMA-UE after 4 weeks, compared to none of the DG patients. Between 4 and 8 weeks of training, patients in the DG tend to show larger improvements when compared to the IG, however, between-group comparisons did not reach significance. Conclusions: Results of this pilot RCT showed that an intensive, specific arm-hand BOOST program, on top of usual care, is feasible and safe in the sub-acute phase post stroke and suggests positive, clinical meaningful effects on upper limb function, especially when delivered in the early sub-acute phase post stroke. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT04584177.

Offseason Workout Recommendations for Baseball Players

PURPOSE OF REVIEW

Offseason training programs are crucial for the baseball athlete. Preparation for the competitive season should be carefully planned to allow long-term athletic success. The two goals of the offseason training program are to optimize performance and reduce injury risk. These goals can only be accomplished with an understanding of the unique physical demands of the sport, and how these demands relate to performance and injury. The purpose of this article is to review the unique demands of baseball training along with current strength and conditioning principles to optimize offseason training for the baseball athlete.

RECENT FINDINGS

Traditional strength and conditioning programs used in other sports may not maximize the qualities necessary for optimal baseball performance. Traditional strength and conditioning exercises, such as squat and deadlift, primarily train sagittal plane movement while frontal and transverse plane movements are likely equally as important for baseball players. Biomechanical studies have shown that trunk rotation power has the largest influence on throwing velocity in pitchers. Programs should also be designed to reduce injury risk for common injuries. The most common injuries in baseball include hamstring strains, throwing arm injuries, paralumbar muscle strains, hip adductor strains, and oblique muscle strains. This review describes the typical periodization phases of the offseason and provides a sample program outlining an offseason program for a professional baseball player from September through February.

Scapular motion is accelerated in asymptomatic individuals with dyskinesis: An observational study

INTRODUCTION

Individuals with shoulder and upper extremity pathology often present with altered scapular motion. Few studies have looked at variations in scapular acceleration as a way of quantifying scapular motion. The purpose was to determine the effectiveness of wireless accelerometers for detecting changes in acceleration in individuals with scapular dyskinesis.

MATERIALS/METHODS

Twenty-seven asymptomatic college students (mean age 24 (SD ± 1.54), 65% female, 93% right handed) were visually screened for scapular dyskinesis using previously described criteria. Of the students recruited, fifteen students were determined to have scapular dyskinesis. After securing a wireless accelerometer (MyoResearch 3D DTS) on the dominate scapula, the participants performed five repetitions of standing scaption from 0 to 140°. Linear scapular accelerations along three orthogonal axes (frontal-y, transverse-z, and sagittal-x) were collected. Intraclass correlation coefficients (ICC_{3, k}) were used to determine the between day intra-rater reliability while a one-way analysis of variance was used to determine differences in acceleration between those with and without dyskinesis.

RESULTS

There was good between day intra-rater reliability for the average of all three axes (ICC = 0.79) and for the x and y axes (ICC > 0.78). Reliability was poor (ICC = 0.31) for the z-axis. There was a significant increase in overall acceleration of the scapula in those with dyskinesis (p = .039). There was also a significant increase in acceleration along the y-axis for those with dyskinesis (p = .003) but not for the other axes (p > .16).

CONCLUSION

Wireless accelerometers reliably quantify scapular acceleration in healthy individuals. In a healthy population with dyskinesis, the overall magnitude of scapular acceleration was greater when compared to a healthy group without dyskinesis.

Periscapular activity in subjects with scapular dyskinesis during push-ups on stable and unstable support surfaces

BACKGROUND: The scapular dyskinesis has been described as a sign of scapular instability due to weakness or imbalance of scapular muscles. OBJECTIVE: The aim of this study was to compare the EMG activity of the periscapular and abdominal muscles of asymptomatic subjects without and with scapular dyskinesis type II during a push-up exercise performed on different surface stability conditions. METHODS: Twenty-seven physically active men were allocated into two groups: the Control group (n= 14); and the Dyskinesis group (n= 13). All participants performed three variations of the push-up exercise: Stable, Push-up with hand instability, and Push-up with hand and feet instability. The EMG activity of serratus anterior, upper (UT), middle (MT) and lower (LT) trapezius, external oblique (EO) and rectus abdominis (RA) was recorded during each task. RESULTS: The control group showed an increase in MT activity (mean difference -3.46 to 8.66) under both instability conditions compared to stable push-ups (p< 0.001). The comparison between groups showed that the control group had higher MT activity (mean difference -10.07 to 13.82) compared to the dyskinesis group under unstable conditions (p< 0.012). CONCLUSION: The insertion of unstable surfaces increased MT activity in the control group only. The insertion of the unstable surface, either the hands or the footrest, did not provide significant effects for the other muscles.

Conservative management in an elderly woman with proximal humeral head fracture and massive rotator cuff tear who refused surgery: A case report

BACKGROUND

Proximal humerus fractures (PHFs) account for between 4% and 10% of all fractures in the elderly people and osteoporosis is frequently related to PHF. Furthermore, rotator cuff (RC) tears are also extremely common, affecting at least 10% of people aged over 60 in the United States. Among shoulder pathologies, the periarticular soft tissue disorders, including the RC, this is considered to be the most common. The incidence of full thickness RC tears increases with age. An aggressive surgical approach is often required for patients with massive RC tear and PHFs to restore the patients' functional daily living activities. To the best of the authors' knowledge, this is the first case report describing a successful conservative management in an elderly patient with a full thickness RC tear and PHF that refused surgery.

CASE DESCRIPTION

This report describes the case of a 90-year-old woman with a massive RC tear who fell over on the sidewalk and sustained a PHF. The patient refused surgery even though it was recommended and prescribed by an orthopaedic surgeon.

INTERVENTION

After having her shoulder immobilized with a brace as prescribed by the orthopaedic physician, the patient began a shoulder rehabilitation program with progressive work load exposure, functional movements and a pain and kinesiophobia education program.

OUTCOMES

After 3 and a half months, the patient achieved full recovery to her pre-injury level of function. Such outcome was assessed using the Numeric Pain Rating Scale (NPRS), the Disability of the Arm, Shoulder and Hand (DASH) scale, the Fear-Avoidance Beliefs Questionnaire (FABQ), the Pain Catastrophysing Scale (PCS), and the Global Rating of Change (GROC) scale.

DISCUSSION AND CONCLUSION

In an elderly patient with a massive RC tear and an undisplaced PHFs, patient education, pain reconceptualization and change of beliefs in combination with progressive work load exposure appeared to be an effective management strategy to achieve a return to the pre-injury level of function.

Validity of Clinical Measurement Instruments Assessing Scapular Function: Insufficient Evidence to Recommend Any Instrument for Assessing Scapular Posture, Movement, and Dysfunction-A Systematic Review

OBJECTIVE

To determine the construct validity, criterion validity, and responsiveness of measurement instruments evaluating scapular function.

DESIGN

Systematic review of measurement properties.

LITERATURE SEARCH

The MEDLINE, Embase, CINAHL, and SPORTDiscus databases were systematically searched from inception until March 2019.

STUDY SELECTION CRITERIA

Studies published in Dutch, English, or German were included when they evaluated at least 1 of the measurement properties of interest. No restrictions were made regarding participants' health status.

DATA SYNTHESIS

Two reviewers independently evaluated study quality using the COSMIN checklist and extracted and analyzed data. Quality of evidence was graded by measurement property for each distinctive type of measurement.

RESULTS

Thirty-one measurement instruments in 14 studies were categorized into instruments to measure scapular posture and movement, and to assess scapular dyskinesis. Quality of evidence was at most moderate for 4 instruments with respect to criterion validity. Of these, criterion validity for instruments measuring scapular protraction/retraction posture and rotation angles up to 120° of thoracohumeral elevation was sufficient. Criterion validity for instruments measuring asymmetrical scapular posture, range of motion, and the lateral scapular slide test was insufficient. Quality of evidence for measurement properties of all other instruments was graded lower.

CONCLUSION

There is currently insufficient evidence to recommend any instrument for the clinical examination of scapular function. Measurement instruments to assess scapular dyskinesis are prone to misinterpretation and should therefore not be used as such. J Orthop Sports Phys Ther 2020;50(11):632-641. doi:10.2519/jospt.2020.9265.

Mechanisms of Modulation of Automatic Scapulothoracic Muscle Contraction Timings

Erected posture provides humans a large shoulder mobility that requires complex automatic muscle synergies to accomplish joint stability needs. This is evident in shoulder abduction, wherein the voluntary activation of glenohumeral muscles is coupled with an automatic recruitment of scapulothoracic muscles. Here, we investigated whether volitional modification of the scapular position, and dynamic scapular elevation, modulate the contraction timing of five shoulder muscles (middle deltoid, upper, middle and lower fiber of the trapezius, serratus anterior) during shoulder abduction. The results show matched contraction timings of the deltoid and upper trapezius across the scapular positions, whereas the contraction timings of the middle and lower fibers of the trapezius change secondary to the scapular position. These results might reflect different central strategies to coordinate the automatic sequences of contraction of the scapulothoracic muscles. This suggest a flexible and adaptable predisposition of the motor control system in exploring alternative solutions to accomplish the functional movement needs, such as the fulfillment of unconstrained movements. Intriguingly, the shoulder abduction may represent a powerful, non-invasive, and straightforward tool to deepen the understanding of the neural basis underlying the voluntary motor command modulation of the out-of-volition automatic muscle contractions.

Effects of adding scapular stabilization exercises to a periscapular strengthening exercise program in patients with subacromial pain syndrome: A randomized controlled trial

BACKGROUND

Interventions focused on the scapula should be considered in treating subacromial pain syndrome (SAPS). However, the effect of adding scapular stabilization exercises to protocols of progressive strengthening of the shoulder complex muscles on a non-multimodal approach remains unclear.

OBJECTIVE

To investigate the effect of adding scapular stabilization exercises, emphasizing retraction, and depression of the scapula, to a progressive periscapular strengthening protocol on disability, pain, muscle strength, and ROM in patients with SAPS.

DESIGN

Randomized, controlled, superiority trial, prospectively registered, two-arms, parallel, blind assessor, blind patient, and allocation concealment.

METHODS

Sixty patients with SAPS were randomly allocated into two groups: Periscapular Strengthening (PSG) or Scapular Stabilization (SSG) exercises. The interventions were performed three times a week for eight weeks. The primary outcome function and secondary outcomes (Pain, kinesiophobia, global perceived effect, satisfaction with treatment, the range of motion, scapula position and muscle strength) were measured in the baseline, four weeks, eight weeks (end of intervention) and 16 weeks after baseline. Shoulder pain and function were assessed by the Brazilian version of the Shoulder Pain and Disability Index (SPADI-Br).

RESULTS

A total of 60 patients were included and randomized to PSG (n = 30) or SSG (n = 30) from March 2016 to June 2017. There were no between group differences in primary and secondary outcomes at any time point.

CONCLUSION

The inclusion of the isolated scapular stabilization exercises, emphasizing retraction and depression of the scapula, to a progressive general periscapular strengthening protocol did not add benefits to self-reported shoulder pain and disability, muscle strength, and ROM in patients with SAPS.

TRIAL REGISTRATION

ClinicalTrials.gov.

Conservative management in a patient with massive rotator cuff tear and rheumatoid arthritis

BACKGROUND

Shoulder pain is one of the most common problems affecting people older than 60 years. Among the shoulder pathologies, the disorders of the periarticular soft tissue (e.g. rotator cuff) are considered to be the most common; moreover, these disorders are found in approximately 75% of patients with seropositive rheumatoid arthritis. The incidence of structural rotator cuff tendon pathology, including full-thickness rotator cuff tendon tears, increases with age. Recent researchers suggested that non-operative treatment of full-thickness rotator cuff tears could be successful in some patients; furthermore, in rheumatoid arthritis patients, there was a greater possibility of developing surgical complications compared with non-rheumatoid arthritis patients.

MATERIALS AND METHODS

A case report of a woman, 72 years old, with rheumatoid arthritis, shoulder pain and pseudo-paralytic arm presented with a massive tear of Supraspinatus and Infraspinatus tendon. In accordance with evidence, the case was managed using pain education and exercise therapy for 2.5 months. The shoulder pain, the function and the range of motion improved following a physiotherapy program.

CONCLUSION

Pain education in combination with exercise therapy was effective for improving pain and function in a full-thickness tear of Supraspinatus and Infraspinatus tendon in a patient also suffering from rheumatoid arthritis.

Measurement of scapular prominence in symptomatic dyskinesis using a novel scapulometer: reliability and the relationship to shoulder dysfunction

BACKGROUND

No previous studies have investigated whether the extent of scapular dyskinesis is associated with shoulder dysfunction. This study aimed (1) to establish the reliability of a scapulometer in patients with shoulder pain and (2) to investigate the related factors associated with shoulder dysfunction.

METHODS

One hundred participants with symptomatic scapular dyskinesis were recruited. Twenty-one participants were involved in the reliability study to test the intrarater and inter-rater reliabilities of the scapulometer in patients with shoulder pain. After demographic data and self-reported Flexilevel Scale of Shoulder Function (FLEX-SF) scores were recorded, all participants were measured with a scapulometer to determine the posterior displacement of the root of the spine (ROS) and the inferior angle (IFA) of the scapula from the thorax. Next, the participants performed 5 trials of bilateral scapular plane elevation for scapular kinematics and electromyographic (EMG) data collection. Stepwise multiple linear regressions were used to determine the relationships between self-reported FLEX-SF scores and potential factors. In addition to scapular displacement, pain level, scapular kinematics, and EMG data were included as independent variables.

RESULTS

The intrarater and inter-rater reliabilities of the scapulometer were excellent (intraclass correlation coefficient [ICC] = 0.93-0.97) and moderate to good (ICC = 0.74-0.81), respectively. The Bland-Altman plots showed no systematic bias between raters in the ROS and IFA measurements. Final stepwise multiple regression models showed that more ROS distance, higher serratus anterior activity, and lower pain level during arm elevation were associated with higher shoulder function (total R² = 0.253).

CONCLUSION

The reliability of the scapulometer in patients with shoulder pain is moderate to excellent. Scapular dyskinesis may be a compensatory strategy to avoid shoulder pain and improve shoulder function.

Scapular Kinematics in Athletes With and Without Rotator Cuff Tendinopathy: A Systematic Review

Context: Rotator cuff tendinopathy is one of the most frequently reported shoulder injuries in athletes of overhead sports. Abnormal scapular kinematics has been proposed as one of the contributing factors of rotator cuff tendinopathy in overhead athletes. Objectives: To review the literature on 3-dimensional scapular kinematics in overhead athletes with and without rotator cuff tendinopathy. Evidence Acquisition: Electronic databases (Cochrane Library, MEDLINE, Embase, and PubMed) were searched from inception to September 2017. In addition, the reference lists of the articles that met the inclusion criteria were also searched. We included studies that compared the changes in 3-dimensional scapular kinematics in athletes with and without rotator cuff tendinopathy. Two reviewers independently examined the quality of studies by using the modified Downs and Black checklist. Evidence Synthesis: A total of 9 studies (a total of 332 athletes, mean age 23.41 [2.62] y) were included in the final analysis. The methodological quality was low (modified Downs and Black checklist = 9/15). Our findings showed a consistent pattern of increased scapular anterior tilting and internal rotation in the dominant shoulders than the nondominant shoulders of athletes who participated in overhead sports. Athletes of overhead sports seem to demonstrate an increase in scapular upward rotation during arm elevation when compared with nonathlete individuals. However, there is no consensus on the scapular kinematics pattern in athletes with rotator cuff tendinopathy when compared with healthy controls. Conclusion: Findings demonstrated that changes in scapular kinematics were observed in overhead athletes. However, all the included studies were cross-sectional studies with small sample size and diverse sports participation, whether changes in scapular kinematics may contribute to rotator cuff tendinopathy in overhead athletes warrants more high-quality prospective studies.

Effect of scapular stabilization exercise program in patients with subacromial impingement syndrome: a systematic review

Scapular stabilization approaches have been a mainstay of therapeutic training programs in the recent past for patients with subacromial im-pingement syndrome, whereas its contributions solely in the clinical outcome of reducing shoulder pain and disability are largely unclear. This systematic review aims to evaluate and summarize the best evi-dence regarding the role of scapular stabilization interventions in allevi-ating shoulder dysfunction among subjects with subacromial impinge-ment syndrome. Six reviewers involved in this systematic review. Liter-ature was retrieved systematically through searching 5 electronic data-bases (PubMed, MEDLINE, CINAHL, Cochrane, and Google Scholar). Articles published from the year 2010 up to and including 2019 were in-cluded. The literature search included clinical trials those intervened subjects with scapular exercises or scapular stabilization exercises or scapular rehabilitation, as an intervention for subacromial impingement syndrome. Seven studies, totaling 228 participants were included in this systematic review. Articles included in this review were graded ac-cording to Lloyd-Smith hierarchy of evidence scale and critically ap-praised with a tool developed by National, Heart, Lung and Blood Insti-tute (United States), named as quality assessment of controlled inter-vention studies tool. There was a significant effect on the scapular sta-bilization exercise program on improving pain and disability among sub-jects with subacromial impingement syndrome. This systematic review provides sufficient evidence to suggest that scapular stabilization exer-cises offers effectiveness in reducing pain and disability among sub-jects with subacromial impingement syndrome. However, more trials with larger sample are needed to provide a more definitive evidence on the clinical outcomes of scapular stabilization exercises among pa-tients with impingement.

Altered Scapular Time Series in Individuals With Subacromial Pain Syndrome

Altered scapular movement in subacromial pain syndrome has been demonstrated using discrete data reduction approach. However, this approach does not consider the data collinearity and variability, and scapular translations are poorly investigated in symptomatic individuals. The purpose of this study was to investigate the scapular rotation and translation of asymptomatic individuals and those with subacromial pain syndrome during arm motions using principal component analysis. Scapulothoracic kinematics were evaluated in 47 participants with subacromial pain syndrome and 50 asymptomatic individuals. The symptomatic group had increased range of scapular anterior/posterior tilt during arm elevation (P = .01, effect size = .59) and arm lowering (P < .01, effect size = .61), and increased range of scapular forward/backward translation during arm lowering (P < .01, effect size = .60) compared with the asymptomatic group. In addition, the symptomatic group had a reduced difference in anterior tilt angular velocities between the early-arm and mid-arm lowering phases and between the mid- and late-arm lowering phases compared with the asymptomatic group (P = .03, effect size = .44). This study demonstrated that scapular anterior/posterior tilt motion and angular velocity and scapular forward/backward translation of symptomatic individuals were different from asymptomatic individuals when considering the entire arm movement.

Comparative study of the differences in shoulder muscle activation according to arm rotation angle

BACKGROUND

Scapular muscle exercise is important for patients with shoulder disorders. Distal variance leads to changes in shoulder muscle activation. Here, we aimed to determine whether scapular muscle activation is affected by different arm rotation angles.

METHODS

Overall, 30 healthy men participated in this study. The subjects were asked to keep their arms at 120 degrees of shoulder flexion while holding a 1.0-kg dumbbell in palms down (pronation) and palms up (supination) positions. Electromyography was used to measure anterior, middle, posterior deltoid, serratus anterior, upper, and lower trapezius muscle activation during the task. The muscle activations of each shoulder were compared between the pronation and supination positions.

RESULTS

Anterior deltoid and serratus anterior activations were significantly higher in supination than in pronation (p < .05). Alternatively, posterior deltoid and lower trapezius muscles were significantly more activated in pronation than in supination (p < .05).

CONCLUSION

Scapular muscle activation changed with arm rotation angle. Arm rotation angle should be assessed to estimate scapular muscle activation during exercise and motion analysis in clinical practice.

Scapular Dyskinesia, the forgotten culprit of shoulder pain and how to rehabilitate

The improper movement of the scapula during shoulder movement is termed scapular dyskinesis and is an often-forgotten cause of pain and dysfunction. The scapula is a key part of the upper limb kinematic chain and is a vital component of the glenohumeral rhythm; which is a major determinant of the efficiency and efficacy of the upper limb. We provide an overview of the complex regional anatomy of the shoulder girdle and how this allows the scapula to act as a both a dynamic and static stabilizer to the upper limb. We explore the normal biomechanics and the aetiology, epidemiology and pathological occurrences which can disrupt the normal function and lead to scapula dyskinesis. Scapula dyskinesis is a poorly understood condition and provides a challenge for the clinician in both diagnosis and management. We provide a summary of the clinical assessment which is most likely to identify the source of the pathology and guides the treatment which is largely rehabilitation of the musculature with focused and specialized physiotherapy.

Superficial Shoulder Muscle Synergy Analysis in Facioscapulohumeral Dystrophy During Humeral Elevation Tasks

Facioscapulohumeral dystrophy (FSHD) is a progressive muscle-wasting disease which leads to a decline in upper extremity functionality. Although the scapulohumeral joint's stability and functionality are affected, evidence on the synergetic control of the shoulder muscles in FSHD individuals is still lacking. The aim of this paper is to understand the neuromuscular changes in shoulder muscle control in people with FSHD. Upper arm kinematics and electromyograms (EMG) of eight upper extremity muscles were recorded during shoulder abduction-adduction and flexion-extension tasks in eleven participants with FSHD and 11 healthy participants. Normalized muscle activities were extracted from EMG signals. Non-negative matrix factorization was used to compute muscle synergies. Maximum muscle activities were compared using non-parametric analysis of variance. Similarities between synergies were also calculated using correlation. The Biceps Brachii was significantly more active in the FSHD group (25±2%) while Trapezius Ascendens and Serratus Anterior were less active (32±7% and 39±4%, respectively). Muscle synergy weights were altered in FSHD individuals and showed greater diversity while controls mostly used one synergy for both tasks. The decreased activity by selected scapula rotator muscles and muscle synergy weight alterations show that neuromuscular control of the scapulohumeral joint is less consistent in people with FSHD compared to healthy participants. Assessments of muscle coordination strategies can be used to evaluate motor output variability and assist in management of the disease.

Clinical assessment methods for scapular position and function. An inter-rater reliability study

Introduction: The aim of this study was to assess the inter-rater reliability of selected static, semi-dynamic, and dynamic test assessment methods for evaluation of scapular positioning and function. Methods: A standardized three-phase (i.e. training, overall agreement, and actual study) protocol for reliability studies was applied on 41 overhead sports participants, aged 18-56 (22 with obvious scapular winging, classified as visibility of the medial or inferior angle border of scapula). Ten scapular test assessment methods (two static, three semi-dynamic, and five dynamic) were evaluated. Results: Bland-Altman plots showed no funnel effects, although systematic bias and significant differences between raters were present in three of the methods. ICC values ranged from 0.71 to 0.80 for the static test assessment methods and from 0.25-0.92 for the semi-dynamic test assessment methods. Three of the five dynamic test assessment methods had ICCs of 0.47-0.68. For the two remaining dynamic test assessment methods, kappa varied between -0.034 and 0.71. Using PABAK, kappa increased to 0.54-0.86. Conclusion: Four scapular test assessment methods (Upper horizontal distance, Lower horizontal distance at max shoulder flexion, Acromial distance, and Winging scapula) showed satisfactory inter-rater reliability. Simple visual observational methods and quantitative distance measurements have better reliability between clinicians than more complex measurements and may be better suited for use in clinical practice.

Therapeutic Interventions for Scapular Kinematics and Disability in Patients With Subacromial Impingement: A Systematic Review

CONTEXT

Impaired scapular kinematics are commonly reported in patients with subacromial impingement syndrome (SIS). Various therapeutic interventions designed to improve scapular kinematics and minimize pain and disability have been described in the literature. However, the short- and long-term benefits of these interventions are unclear.

OBJECTIVE

To determine the effects of specific short- and long-term therapeutic interventions on scapular kinematics and disability in patients with SIS.

DATA SOURCES

We searched PubMed, CINAHL, and SPORTDiscus databases from their origins to January 2018 using a combination of the key words scapular kinematics AND (shoulder dysfunction OR subacromial impingement) and conducted a manual search by reviewing the references of the identified papers.

STUDY SELECTION

Studies were included if (1) preintervention and postintervention measures were available; (2) patient-reported outcomes were reported; (3) scapular kinematics measures at 90° of ascending limb elevation in the scapular plane were included; (4) SIS was diagnosed in participants or participants self-reported symptoms of SIS; (5) they were original clinical studies published in English; and (6) the sample sizes, means, and measure of variability for each group were reported.

DATA EXTRACTION

Seven studies were found. Sample sizes, means, and standard deviations of scapular upward rotation, posterior tilt, and internal rotation at 90° of ascending limb elevation on the scapular plane and the Disabilities of the Arm, Shoulder and Hand scores were extracted.

DATA SYNTHESIS

Standardized mean differences between preintervention and postintervention measures with 95% confidence intervals (CIs) were calculated. We observed that the Disabilities of the Arm, Shoulder and Hand scores improved (mean difference = 0.85; 95% CI = 0.54, 1.16) but did not observe changes in scapular upward rotation (mean difference = -0.04; 95% CI = -0.31, 0.22), posterior tilt (mean difference = -0.09; 95% CI = -0.32, 0.15), or internal rotation (mean difference = 0.06; 95% CI = -0.19, 0.31).

CONCLUSIONS

The short- and long-term therapeutic interventions for SIS improved patient-reported outcomes but not scapular kinematics. The identified improvements in shoulder pain and function were not likely explained by changes in scapular kinematics.

The Impact of Decreased Scapulothoracic Upward Rotation on Subacromial Proximities

BACKGROUND

Decreased scapulothoracic upward rotation has been theorized to increase an individual's risk for rotator cuff compression by reducing the clearance for the tendons in the subacromial space (ie, subacromial proximities). However, the impact of decreased scapulothoracic upward rotation on subacromial proximities has not been tested during dynamic in vivo shoulder motion.

OBJECTIVE

To determine the impact of decreased scapulothoracic upward rotation on subacromial proximities.

METHODS

Shoulder kinematics were quantified in 40 participants, classified as having high or low scapulothoracic upward rotation, during scapular plane abduction using single-plane fluoroscopy and 2-D/3-D shape-matching. Subacromial proximities were calculated as (1) the normalized minimum distance between the coracoacromial arch and humeral rotator cuff insertion, and (2) the surface area of the humeral rotator cuff insertion in immediate proximity to the coracoacromial arch. The effect of decreased scapulothoracic upward rotation on subacromial proximities was assessed using 2-factor mixed-model analyses of variance. The prevalence of contact between the coracoacromial arch and rotator cuff was also quantified.

RESULTS

Subacromial distances were generally smallest below 70° of humerothoracic elevation. With the arm at the side, the normalized minimum distance for participants in the low scapulothoracic upward rotation group was 34.8% smaller compared to those in the high upward rotation group (P = .049). Contact between the coracoacromial arch and rotator cuff tendon occurred in 45% of participants.

CONCLUSION

Decreased scapulothoracic upward rotation shifts the range of risk for subacromial rotator cuff compression to lower angles. However, the low prevalence of contact suggests that subacromial rotator cuff compression may be less common than traditionally presumed. J Orthop Sports Phys Ther 2019;49(3):180-191. Epub 18 Jan 2019. doi:10.2519/jospt.2019.8590.

Alternative scapular stabilization exercises to target strength, endurance and function of shoulders in tetraplegia: A prospective non-controlled intervention study

OBJECTIVE

Scapular stabilization exercises (SSE) are well-established for the able-bodies. The aim of the current study is to access the potential benefits of SSE on isometric internal and external rotator strength, endurance and function of the shoulder in persons with tetraplegia, throughout a 12-week exercise program consisting of five resisted movements with elastic bands.

DESIGN

Prospective non-controlled intervention study.

SETTING/PARTICIPANTS/INTERVENTIONS

A convenience sample of 17 subjects (age, 40.0±10.0 years old) with SCI was recruited from the University Hospital at the State University of Campinas (UNICAMP) from March 2015 to February 2016. They performed 5-resisted-SSE for 12 weeks, using Thera-band® elastic bands. Four evaluations were required: Baseline1, Baseline2, 6W and 12W.

OUTCOME MEASURES

The dependent variables were isometric internal and external rotation strength, flexion and abduction endurance and the Disabilities of the Arm, Shoulder and Hand (DASH) score.

RESULTS

Isometric external rotation strength and flexion endurance increased after SSE and were classified as "clinically relevant" using minimal importance difference (MID). Abduction endurance increased but it was classified as "not clinically relevant". DASH score reported no significant differences but it was classified as "potentially clinically relevant". Correlations were observed among time since injury and endurance improvements.

CONCLUSION

This study demonstrated that specific training of the scapula muscles shows a benefit for shoulder strength, endurance and function of the shoulder in subjects with tetraplegia and should be part of the rehabilitation program. Besides, the SSE can be performed by subjects with tetraplegia themselves on a regular basis.