Specific kinematics and associated muscle activation in individuals with scapular dyskinesis

The latissimus dorsi creates a dynamic track for the inferior angle of the scapula during arm abduction in humans

BACKGROUND

The importance of several scapulothoracic muscles, including trapezius and serratus anterior, in maintaining physiological scapula kinematics has been highlighted in the past. However, the relationship between the scapula and the latissimus dorsi muscle remains unclear. Our clinical surgical observation is that the latissimus dorsi does not directly attach but rather runs superficial to the inferior angle of the scapula. Based on this observation, we hypothesise that the latissimus dorsi creates a dynamic track on which the scapula glides under the muscle belly during elevation of the arm, creating the latissimus-scapula overlap (LSO).

METHODS

All consecutive patients who had a whole-body computed tomography scan (CT) in case of polytrauma evaluation between 2018 and 2021, with complete depiction of the scapula and latissimus dorsi muscle, were analysed. 150 shoulders in 90 patients with arms up were matched according to their age (within five years), gender, and affected side with 150 shoulders in 88 patients with arms down. Patients with pathologies of the upper extremities or thorax that potentially could alter LSO measurements were excluded. LSO was calculated as a ratio of the measured area of the latissimus dorsi projection on the scapula and the total scapula area.

RESULTS

The mean age of the 178 patients (48 females; 13 males) was 60 years. The arms-up group showed a significantly higher LSO than the arms-down group (19.9 ± 6.3% vs. 2.7 ± 2.2%; p < 0.0001). In the arms-up group, approximately one fifth of the scapula was overlapped inferiorly by the muscle belly of the latissimus dorsi, contrary to the almost non-existing LSO in the arms-down group.

CONCLUSION

With arms up, humans show a significantly higher LSO in comparison to arms down indicating that the latissimus dorsi indeed creates a dynamic track on which the scapula is forced to travel during abduction of the arm. This finding of increased LSO during the elevation of the arm warrants further consideration of the role of the latissimus dorsi in scapula kinematics and potentially scapular dyskinesis.

LEVEL OF EVIDENCE

Level two diagnostic study.

Effect of scapular stabilization exercises on subacromial pain (impingement) syndrome: a systematic review and meta-analysis of randomized controlled trials

Objective

To evaluate the effectiveness of scapular stabilization exercises (SSE) in the treatment of subacromial pain syndrome (SAPS).

Methods

Clinical randomized controlled trials (RCTs) on SSE in the treatment of SAPS were searched electronically in PubMed, Science Direct, Cochrane Central Register of Controlled Trials (CENTRAL), EBSCOhost, Physiotherapy Evidence Database (PEDro), Web of Science, and other databases from 2000 to 2022, supplemented by manual search. Final RCTs were selected based on inclusion and exclusion criteria, and the Physiotherapy Evidence Database scale was used to evaluate the methodological quality of the study. A meta-analysis was conducted on data using the RevMan5.4 software.

Results

Eight RCTs involving 387 participants were included. The meta-analysis showed that the experimental group (SSE) had greater improvements in the Visual Analog Scale score [Weighted Mean Difference (WMD) = -0.94, 95% CI (-1.23, -0.65), p < 0.001] and the Shoulder Pain and Disability Index score [WMD = -10.10, 95% CI (-18.87, -1.33), p = 0.02] than the control group (conventional physical therapy). However, range of motion (ROM) was not found to be greater in the experimental group than in the control group.

Conclusion

Existing evidence moderately supports the efficacy of SSE for reducing pain and improving function in SAPS, without significant improvement in ROM. Future research should focus on larger, high-quality, standardized protocols to better understand SSE's effects across diverse SAPS populations, treatment, and outcome measures.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=307437, CRD42022307437.

Effects of slouched sitting posture on clavicular and scapular orientations and movements in individuals with neck pain with scapular dysfunction

BACKGROUND

It has been suggested that sitting posture affects clavicular, scapular and spinal kinematics, however its effects in people with neck pain and scapular dysfunction remain unknown. The study aimed to determine the clavicular and scapular kinematics in different sitting postures in patients with neck pain and scapular dysfunction.

METHODS

Thirty-four participants with neck pain and scapular dysfunction were recruited into the study. Kinematics of the clavicle and scapula were recorded using motion analysis at rest and during arm elevation (at 30, 60, 90, and 120 degrees) in a slouched and upright sitting posture.

RESULTS

Compared to the upright sitting posture, the slouched sitting posture had increased clavicular protraction and elevation as well as scapular internal rotation and anterior tilt at rest and during the arm raising and lowering phases (at 30, 60, 90, and 120 degrees) (p < 0.05). The slouched sitting also had increased scapular upward rotation in the lowering phase at all angles (p < 0.05).

SIGNIFICANCE

The slouched sitting posture has a significant influence on clavicular and scapular kinematics. Awareness of good sitting posture should be encouraged in patients with neck pain and scapular dysfunction.

Shoulder kinetic during pitching in baseball players with scapular dyskinesis

INTRODUCTION

Shoulder injuries in baseball players cause excessive shoulder load during pitching and scapular dyskinesis (SD). However, the characteristics of pitching kinetics in the shoulder joint with SD are unclear. This study aimed to investigate the effect of SD on pitching kinetics in the shoulder joint of baseball players.

METHOD

Seventy-two college and independent league baseball players participated in the study. The pitching motion was measured using an 18-camera motion-capture system. SD was classified into four types (I-IV) using the scapular dyskinesis test (SDT). The pitching kinetics data were analyzed.

RESULTS

The agreement of SD in this study was 56/72 (77.8%). SD were classified into 31 abnormal group (type I-Ⅲ) and 25 control group (type Ⅳ). Three participants with measurement failure during the pitching motion analysis were excluded from the analysis. The abnormal group showed a larger maximum value of the glenohumeral normalized anterior joint force than the control group.

CONCLUSIONS

These results suggest that an increase in GH anterior force during pitching causes an excessive increase in external rotation of the GH with an insufficient posterior tilt of the scapula with SD. Therefore, baseball pitching with SD may involve shoulder injuries owing to excessive shoulder load during pitching.

Comparison of the activation and mechanical properties of scapulothoracic muscles in young tennis players with and without scapular dyskinesis: an observational comparative study

BACKGROUND

In tennis athletes with scapular dyskinesis, the activation of the scapulothoracic muscles during serve is not known. Also, the mechanical properties (tone, elasticity, and stiffness) of the scapulothoracic muscles of the tennis athletes with scapular dyskinesis are likely to change. The study aimed to evaluate the activation of the scapulothoracic muscles while performing tennis serve and to determine the changes in the mechanical properties of the same muscles in young tennis athletes with scapular dyskinesis.

METHODS

Seventeen tennis athletes with scapular dyskinesis aged between 11 and 18 years (the scapular dyskinesis group) and age- and gender-matched 17 asymptomatic tennis athletes (the control group) were included in the study. Activation of scapulothoracic muscles (descending-transverse-ascending trapezius and serratus anterior) in the 3 phases (preparation, acceleration, and follow-through) of the serve was evaluated using surface electromyography, and the mechanical properties of the same muscles were measured at rest by myotonometry.

RESULTS

Ascending trapezius activation in the follow-through phase was lower in the scapular dyskinesis group compared with the control group (mean difference 95% confidence interval: -22.8 [-41.2 to -4.5]) (P = .017). The tone and stiffness of the transverse trapezius (P = .043 and P = .017, respectively) were higher, whereas the same parameters of the ascending trapezius were lower (P = .008 and P = .010, respectively) in the scapular dyskinesis group compared with the control group.

CONCLUSIONS

Activation of the ascending trapezius and the tone and stiffness of the transverse-ascending trapezius were altered in tennis athletes with scapular dyskinesis. Implementations to improve these changes can be included in the rehabilitation or training programs of young tennis athletes with scapular dyskinesis.

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.

Effects of core stability on shoulder and spine kinematics during upper limb elevation: A sex-specific analysis

BACKGROUND

Upper limb elevation begins with core stabilization, but the effects of core stability on shoulder and spine kinematics are unknown. Sex differences also exist in shoulder kinematics and core stability.

OBJECTIVE

To clarify the effects of core stability on shoulder and spine kinematics during upper limb elevation by taking sex into account.

DESIGN

Cross-sectional.

METHODS

The Sahrmann Core Stability Test, lumbar spine motor control test battery, and Y Balance Test (lower and upper quarters) were performed in 50 healthy young adults. For each test, a principal component (PC) analysis was conducted according to sex; the overall core stability score was calculated. The top and bottom third of the PC scores were defined as high and low score groups, respectively (each group: nine males and eight females). Shoulder and spine kinematics during upper limb elevation were compared separately for males and females.

RESULTS

Spinal extension was greater in the low score group by a maximum of 1.9° in males (P < .001; η² = 0.068) and 1.6° in females (P < .001; η² = 0.141). In the low score group of females, the scapular posterior tilt was a maximum of 5.6° smaller (P < .001; η² = 0.221) and glenohumeral elevation was a maximum of 4.5° larger (P < .001; η² = 0.113) than the high score group of females.

CONCLUSION

Core stability affected spine and female scapular and glenohumeral kinematics during upper limb elevation. Core stability may be one of the potential contributors to shoulder kinematics, particularly in females.

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.

Within-Subject Changes in Shoulder Girdle Muscle Activation After Soft Tissue Mobilization of the Upper Trapezius

Objective

The purpose of this study was to investigate the effect of the integrated neuromuscular inhibition technique (INIT) of the upper trapezius (UT) on shoulder muscle activity in chronic shoulder pain.

Methods

Twenty-two patients (mean age 42.5 ± 16.07) with chronic unilateral shoulder pain with UT myofascial trigger points (MTrPs) (n = 27) and scapular dyskinesis received a single session of INIT (∼15 minutes for each MTrP). The pain on the visual analog scale, along with surface electromyographic activity, maximum voluntary contraction in % (in arm raising and lowering in scapular plane), and pressure pain threshold (PPT) of 5 girdle muscles UT, lower trapezius, serratus anterior, middle deltoid, and infraspinatus were measured before and immediately after treatment. Wilcoxon signed-rank test was used for analysis (at α ≤ 0.05).

Results

Muscle activity of all the muscles, especially the lower trapezius, was reduced during arm raising in the scapular plane (76.69%-71.14% [p = 0.003]). UT activity decreased during arm lowering also (56.70%-45.99% [p ˂ 0.001]). The intensity of shoulder pain reduced (50.50 mm to 22 mm, [p ˂ 0.001]), and PPT values of all 5 muscles improved post-treatment.

Conclusion

The findings of this study provide preliminary evidence for the application of a single session of INIT on UT MTrPs in reducing activity in the scapular muscles, improving shoulder pain, and PPT in chronic unilateral shoulder pain.

Impairment of scapular control in individuals with chronic obstructive pulmonary disease (COPD): Systematic review and meta-analysis

BACKGROUND

Upper quadrant geometrical changes in individuals with chronic obstructive pulmonary disease (COPD) appear to have negative influences on geometrical arrangements of the thorax and scapula.

OBJECTIVE

The purpose of this systematic review was to assess the impairment of scapular control in individuals with COPD as compared with healthy controls.

METHODS

We systematically searched seven electronic databases from inception to June 2021 and updated the searches again in December 2021. Eligible studies included the participants with COPD and compared scapular control outcomes (scapular/shoulder kinematic or related muscle activity) with a control group. Two researchers independently searched for, screened, extracted data from, and evaluated the quality of all articles.

RESULTS

Seven studies met the inclusion criteria and only five studies with 190 subjects were included in the meta-analyses. Subgroup analyses showed that the control group exhibited more scapular anterior tilt (SMD: 0.46; 95% CI: 0.01 to 0.90) and shoulder flexion (SMD: -1.02; 95% CI: -1.79 to -0.26) as compared with the COPD group. Conversely, the COPD group exhibited more scapular elevation (SMD: -1.03; 95% CI: -1.69 to -0.37), internal rotation (SMD: -1.65; 95% CI: -3.19 to -0.10), and protraction (SMD: -0.75; 95% CI: -1.18 to -0.32) compared with the control group. All other outcomes revealed non-significant findings.

CONCLUSION

This review demonstrated scapular control impairments, such as scapular elevation, internal rotation, protraction, and anterior tilt in a static position in patients with COPD. To validate these findings, high-quality randomized control trials with large sample sizes and reliable outcome measures should be conducted.

Shoulder Kinesio Taping Does Not Change Biomechanical Deficits Associated With Scapular Dyskinesis

Observable scapular dyskinesis is associated with biomechanical deficits. Preventative interventions aimed at correcting these deficits may aid in preventing the development and resolution of shoulder pain. Our purpose was to investigate the effects of kinesio taping (KT) on common biomechanical deficits associated with scapular dyskinesis and shoulder pain. Participants (n = 51) with observable scapular dyskinesis, and without shoulder pain were randomized to KT, KT-placebo, or a no-treatment control group. Measurements taken before, immediately after taping, and 3 days later included pectoralis minor muscle length, lower trapezius muscle strength, scapular upward rotation angle at 0° to 120° in scapular plane humeral elevation and acromiohumeral distance. There were no changes in scapular upward rotation, lower trapezius strength, and acromiohumeral distance immediately after taping or 3 days later compared to baseline (P > .05). The pectoralis minor increased in length in the KT group on day 3 compared to directly after taping (P = .03), but no difference between groups or interaction between time and group were determined (P > .05). Scapular dyskinesis prevalence did not change over time in any group (P > .05). In people with scapular dyskinesis free from shoulder pain, KT applied to the shoulder cannot be recommended to ameliorate the biomechanical deficits associated with shoulder pain.

Scapular dyskinesis type is associated with glenohumeral joint and scapular kinematic alteration during pitching motion in baseball players

INTRODUCTION

Scapular dyskinesis (SD) is associated with an increased risk of throwing-related shoulder injury onset, resulting in abnormalities in glenohumeral joint (GH) and scapular motions during pitching. The effects of SD on shoulder motion during pitching remain unknown. This study aimed to investigate kinematic alterations in GH and scapular motions during pitching in baseball players with type I SD.

METHODS

Sixty-seven university and independent-league baseball players with and without SD were included. Pitching motion was measured using an optical three-dimensional motion capture system, and a SD test was conducted to evaluate SD. SD was classified into types I-IV. The inter-rater reliability of SD assessment was calculated using kappa coefficients. Three-dimensional GH and scapular kinematics during pitching motion were analyzed.

RESULTS

The percentage of agreement representing the inter-rater reliability of SD assessment was 77.6% (52/67; kappa coefficient: 0.72). Overall, 24 and 27 participants were categorized into abnormal (type I SD) and normal group (type IV SD), respectively, with normal scapular motion; one individual with type III SD was excluded. The abnormal group exhibited a significantly increased GH external rotation angle (9°) and decreased scapular posterior tilt angle (6°) during the maximum external rotation period compared with the normal group.

CONCLUSIONS

Baseball players in the abnormal group showed increased GH motion and decreased scapular motion during pitching. The SD test for the evaluation of type I SD can help predict excessive GH external rotation and decreased scapular posterior tilt during pitching.

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.

Effects of Intended Scapular Posterior Tilt Motion on Trapezius Muscle Electromyography Activity

The intended scapular motion is a strategy to strengthen the lower trapezius (LT). However, few studies have explored the effects of the intended scapular posterior tilt motion on selective LT activation. Thus, the present study investigated the effect of the intended scapular posterior tilt on the electromyography (EMG) activity of trapezius muscles during prone shoulder horizontal abduction (PSHA). Eighteen asymptomatic men performed three types of PSHA: (1) preferred PSHA, (2) PSHA with the intended scapular posterior tilt, and (3) PSHA with the intended scapular posterior tilt and trunk extension. EMG activity of the upper trapezius (UT), middle trapezius (MT), and LT were measured during PSHAs. Scapular posterior tilt angle, with and without the intended scapular posterior tilt, were measured using inclinometer. The results indicated that LT muscle activity increased when scapular posterior tilt was applied with and without trunk extension (14-16%), compared to the preferred condition, during PSHA (p < 0.05). However, the addition of trunk extension to PSHA with the intended scapular posterior tilt increased the UT muscle activity (28%) and the UT/LT (29%) and UT/MT (31%) ratios (p < 0.05). The scapular posterior tilt angle was higher (15%) when applying the intended scapular posterior tilt (p = 0.020). These findings suggest that the intended scapular posterior tilt may be a useful strategy for selective LT muscle activation.

Scapulothoracic Dyskinesis: A Concept Review

PURPOSE OF REVIEW

Scapulothoracic dyskinesis (SD) occurs when there is a noticeable disruption in typical position and motion of the scapula, which can result in debilitating pain. The purpose of this review is to describe the current knowledge regarding the diagnosis and management of scapulothoracic dyskinesis by providing an evidence-based overview of clinical exams and treatment modalities available for orthopedic surgeons and provide insight into which treatment modalities require further investigation.

RECENT FINDINGS

SD is highly prevalent in athletes, particularly those participating in overhead activities (e.g., baseball, tennis, and swimming) and can coexist with several shoulder pathologies. A holistic approach in the diagnosis of SD has been supported in the literature; however, it is important to recognize that diagnosis is currently limited to the absence of a quantitative SD clinical assessment. The main goal of the treatment of SD is to regain proper scapular positioning and dynamics. The standard of care for the management of SD is conservative interventions aimed at optimizing scapular kinematics. Surgical intervention is only considered in the presence of concomitant pathology requiring surgery. Due to the complexity of coordinated movement of the shoulder girdle, recent literature has begun to move away from the use of traditional orthopedic tests, in favor of a more system-based approach for the diagnosis of SD. We present a concise review of clinical exams and treatment modalities available for orthopedic surgeons in the management of SD.

A computer tablet software can quantify the deviation of scapula medial border from the thoracic wall during clinical assessment of scapula dyskinesis

PURPOSE

Aim of this study is to establish an objective and easily applicable method that will allow clinicians to quantitatively assess scapular dyskinesis during clinical examination using a computer tablet software. Hypothesis is that dyskinetic scapulae present greater motion-deviation from the thoracic wall-compared to the non-dyskinetic ones and that the software will be able to record those differences.

METHODS

Twenty-five patients and 19 healthy individuals were clinically evaluated for the presence of dyskinesis or not. According to the clinical diagnosis, the observations were divided into three groups; A. Dyskinetic scapulae with symptoms (n = 25), B. Contralateral non-dyskinetic scapulae without symptoms (n = 25), C. Healthy control scapulae (n = 38). Then, all individuals were tested using a tablet with the PIVOT™ image-based analysis software (PIVOT, Impellia, Pittsburgh, PA, USA). The motion produced by the scapula medial border and inferior angle deviation from the thoracic wall was recorded.

RESULTS

The deviation of the medial border and inferior angle of the scapula from the thoracic wall was 24.6 ± 7.3 mm in Group A, 14.7 ± 4.9 mm in Group B, and 12.4 ± 5.2 mm in Group C. The motion recorded in the dyskinetic scapulae group was significantly greater than both the contralateral non-dyskinetic scapulae group (p < 0.01) and the healthy control scapulae group (p < 0.01).

CONCLUSION

The PIVOT™ software was efficient to detect significant differences in the motion between dyskinetic and non-dyskinetic scapulae. This system can support the clinical diagnosis of dyskinesis with a numeric value, which not only contributes to scapula dyskinesis grading but also to the evaluation of the progress and efficacy of the applied treatment, thus providing a feedback to the clinician and the patient.

LEVEL OF EVIDENCE

IV, laboratory study.

Clinical Factors Related to Improved Scapular Control After a Scapular Conscious Control Program in Symptomatic Overhead Athletes: Secondary Analysis of a Randomized Controlled Trial

Background:

Predictive variables associated with the effects of a scapular conscious control program should be identified and used to guide rehabilitation programs.

Purpose:

To determine whether potential factors are associated with the success of scapular muscle balance with an early control program in patients with subacromial pain and scapular dyskinesis.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 38 amateur overhead athletes with subacromial pain and medial border prominence were recruited. They performed progressive conscious control of scapular orientation during 45° and 90° of arm elevation. Stepwise logistic regression and receiver operating characteristic curve were used to determine the optimal cutoff point of related factors for success or failure of the program. Potential factors including pain level during activity, pain duration, anterior/posterior shoulder flexibility, forward shoulder posture, posterior displacement of root of spine and inferior angle, scapular kinematics, and muscle activation before conscious control program were recorded as independent variables. Successful control defined as decreases of the upper trapezius/serratus anterior ratio in 2 consecutive trials of the 90° program or failure in the program was used as a dependent variable.

Results:

Having a posterior displacement of the inferior angle of the scapula of ≤16.4 mm and scapular posterior tipping during arm elevation of ≤3.3° (collected before the control program) were associated with the success of the program (R² = 0.286; P < .05). Additionally, participants with each or both variables present at baseline had probabilities of success of 78% and 95%, respectively.

Conclusion:

The value of scapular posterior displacement and posterior tilt should be considered before early scapular control program. Other factors related to the success of the program should be found due to the limited variance explained in the regression model.

Improving the staging of neck injuries using a new index, the Neck Functional Holistic Analysis Score: Clustering approach to determine degrees of impairment

Background

Traumatic cervical spine injuries are amongst the traffic injuries that can cause most harm to a person. Classifying subtypes of clinical presentations has been a method used in other pathologies to diagnose more efficiently and to address the appropriate treatment and the prognosis. The management of patients suffering from cervical injuries could be improved by classifying the severity of the impairment. This will allow clinicians to propose better treatment modalities according to the severity of the injury.

Materials and methods

The present study is a retrospective cohort study performed with the clinical data from 772 patients stored at Fisi-(ON) Health Group. All the patients treated for cervical spine injuries are evaluated using the EBI-5^® system, which is based on inertial measurement unit (IMU) technology. The normalized range of motion of each patient was incorporated into a single index, the Neck Functional Holistic Analysis Score (NFHAS).

Results

Clustering analysis of the patients according to their NFHAS resulted in five groups. The Kruskal-Wallis H test showed that there were statistically relevant differences in the ROM values and NFHAS of the patients depending on the cluster they were assigned to: FE X²(4) = 551.59, p = 0.0005; LB ROM X²(4) = 484.58, p = 0.0005; RT ROM X²(4) = 557.14, p = 0.0005; NFHAS X²(4) = 737.41, p = 0.0005. Effect size with ηp² for the comparison of groups were: FE = 0.76, LB = 0.68, RT = 0.76 and NFHAS = 0.96.

Conclusion

The NFHAS is directly correlated to the available ROM of the patient. The NFHAS serves as a good tool for the classification of cervical injury patients. The degree of impairment shown by the cervical injury can now be staged correctly using this new classification.

Shoulder pain and scapular dyskinesis associated with lower trapezius dysplasia - A case report

BACKGROUND

Scapular dyskinesis (SD) has been associated with shoulder soft-tissue tightness as well scapular muscle strength and/or activation deficits. Inadequate development of the trapezius muscle (trapezius dysplasia) is a relatively rare condition inconsistently associated with shoulder dysfunction.

CASE DESCRIPTION

a 24-year old male complaining of left scapular area pain associated with SD and scapular muscle weakness was noted to present with a smaller ipsilateral lower trapezius (LT). Further inquiry including electromyography, rehabilitative ultrasound imaging (RUSI) and magnetic resonance imaging ruled out nerve palsy and demonstrated a hypoplastic left LT. This led to a greater emphasis on serratus anterior (SA) training along with the addition of neuromuscular electrical stimulation of the LT.

OUTCOMES

Following 12 sessions over a 5-month period the patient reported no pain or functional deficits, and was able to resume all recreational activities. The patient's subjective shoulder value increased from 55% to 80%, and LT strength was markedly improved.

DISCUSSION

Scapular muscle dysplasia may represent a less recognized cause of SD. A more thorough inspection of scapular muscle shape and orientation, possibly augmented by RUSI may be indicated in patients presenting with SD. Neuromuscular electrical stimulation is a potentially useful modality for addressing scapular muscle activation and strength deficits and future research into its efficacy under these circumstances may be warranted.

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 Dyskinesis: From Basic Science to Ultimate Treatment

Background: This study intends to summarize the causes, clinical examination, and treatments of scapular dyskinesis (SD) and to briefly investigate whether alteration can be managed by a precision rehabilitation protocol planned on the basis of features derived from clinical tests. Methods: We performed a comprehensive search of PubMed, Cochrane, CINAHL and EMBASE databases using various combinations of the keywords “Rotator cuff”, “Scapula”, “Scapular Dyskinesis”, “Shoulder”, “Biomechanics” and “Arthroscopy”. Results: SD incidence is growing in patients with shoulder pathologies, even if it is not a specific injury or directly related to a particular injury. SD can be caused by multiple factors or can be the trigger of shoulder-degenerative pathologies. In both cases, SD results in a protracted scapula with the arm at rest or in motion. Conclusions: A clinical evaluation of altered shoulder kinematics is still complicated. Limitations in observing scapular motion are mainly related to the anatomical position and function of the scapula itself and the absence of a tool for quantitative SD clinical assessment. High-quality clinical trials are needed to establish whether there is a possible correlation between SD patterns and the specific findings of shoulder pathologies with altered scapular kinematics.

Activation Profile of Scapular Stabilizing Muscles in Asymptomatic People: Does Scapular Dyskinesis Have an Impact on It?

OBJECTIVE

The aim of the study was to assess the activation profile of scapular stabilizing muscles in dyskinetic asymptomatic people.

DESIGN

This is a noninterventional observational study. Two groups of 20 people were included in the study. The first group involved asymptomatic athletes with scapular dyskinesis. The second one included athletes without scapular dysfunction. Muscle activation of upper trapezius, lower trapezius, and serratus anterior were recorded by a surface electromyography during shoulder flexion and shoulder abduction, in unloaded and loaded conditions.

RESULTS

A significant increase of the activity of the upper trapezius (between 23% and 31%) and a significant decrease of the activity of the lower trapezius (between 32% and 65%) were observed in the dyskinetic group in comparison with the nondyskinetic group in asymptomatic athletes. A significant increase between 17% and 31% of the activity of the serratus anterior was also observed in dyskinetic people. Likewise, a significant increase approximately 24%-61% and 23%-70% was noted respectively in upper trapezius/lower trapezius and upper trapezius/serratus anterior ratio's in the dyskinetic group.

CONCLUSIONS

An alteration of periscapular muscular activation exists in dyskinetic asymptomatic people. Future studies will be needed to know whether those alterations increase the risk of shoulder injuries.

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.

Effects of trapezius kinesio taping on scapular kinematics and associated muscular activation in subjects with scapular dyskinesis

STUDY DESIGN

Crossover repeated-measure design.

INTRODUCTION

Scapular dyskinesis rehabilitation programs that focus on inhibiting upper trapezius (UT) and activating the lower trapezius (LT) may assist in restoring scapular movements. We hypothesized that taping may be able to normalize scapular movements and associated muscular recruitment.

PURPOSE OF THE STUDY

The purpose of this study was to investigate the immediate effects of kinesio taping over trapezius on scapular kinematics and muscular activation in different dyskinesis patterns. We expected that taping can improve scapular kinematics and muscular activation in subjects with dyskinesis.

METHODS

Fifty-four participants with inferior angle prominence (pattern I), medial border prominence (pattern II), and mixed pattern (pattern I + II) were recruited. Kinesio taping was applied over 3 parts of trapezius muscles, including UT, middle trapezius (MT), and LT. The scapular kinematics and electromyographic data of trapezius and serratus anterior were collected during scapular plane elevation without taping and after each taping application.

RESULTS

UT taping decreased UT activity (5%-7%; P = .001-.003) in 72% of participants with pattern II and pattern I + II dyskinesis, with increased posterior tipping (2.2°-2.5°; P = .003) in pattern II dyskinesis. MT taping increased UT activity (3%; P = .003) in 48% of participants with pattern II dyskinesis.

DISCUSSION

The taping over the trapezius muscle may help to restore coordinated scapular muscle balance and increased upward rotation of the scapula, especially in pattern II dyskinesis. Although no electromyography or kinematic difference was found with LT taping in each dyskinesis pattern, methods of applying LT taping need to be further investigated.

CONCLUSION

Reduced UT muscle activity and scapular posterior tipping are appropriate when applying taping over UT muscle in patterns II and I + II dyskinesis. Caution should be taken when applying taping over MT and LT muscles in terms of increased UT activity, especially in pattern II dyskinesis.

Exercise therapy may affect scapular position and motion in individuals with scapular dyskinesis: a systematic review of clinical trials

BACKGROUND

Therapeutic exercise for scapular muscles is suggested to be effective in reducing shoulder pain in patients with rotator cuff disorders, whereas its effectiveness on scapular position and motion has remained unclear. Therefore, the aim of this systematic review was to investigate whether exercise therapy improves scapular position and motion in individuals with scapular dyskinesis.

METHODS

This study is a wide systematic review including any type of clinical trial in which the effect of any type of therapeutic exercise, including scapular muscle strengthening, stretching, and scapular stabilization exercise, is investigated in adult participants.

RESULTS

Twenty studies were included in this systematic review. Studies were categorized on the basis of the techniques they used to measure scapular position and motion and the included participants. Methodologic quality of the studies was assessed by the Cochrane tool of assessing the risk of bias. Eight studies used 3-dimensional techniques for measuring scapular motions. Among them, 5 studies showed significant effects of exercise on scapular motion, of which 3 studies investigated individuals with subacromial impingement syndrome (SIS). The other 12 studies used 2-dimensional measurement techniques, of which 8 studies reported significant effects of exercise on scapular position and motion both in SIS patients and in asymptomatic individuals. However, their methodologic quality was debatable. Therefore, there was conflicting evidence for the effect of exercise on scapular dyskinesis.

CONCLUSION

There is a lack of evidence for beneficial effects of exercise in improving scapular position and motion in individuals with scapular dyskinesis. However, exercise is beneficial in reducing pain and disability in individuals with SIS.

Alterations in the 3-dimensional scapular orientation in patients with non-specific neck pain

BACKGROUND

Although it is thought that there is a relationship between neck pain and scapular dysfunction, there are controversial results and no clear information in the literature regarding this issue. This study aimed to investigate the alterations in the 3-Dimensional scapular orientation on patients with non-specific neck pain.

METHOD

Thirty-four patients with chronic non-specific neck pain [age, 29.1 (5) years; height, 165.3 (6.1) centimeters; weight, 62.1 (9.6) kilogram] and 29 healthy controls [age, 28.2 (3.3) years; height, 166.8 (8.1) centimeters; weight, 60.9 (8.5) kilogram] were included in the study. 3-Dimensional scapular kinematics were obtained during arm elevation and lowering trials in the sagittal, scapular, and frontal planes.

FINDINGS

Compared to healthy controls, the patients with neck pain demonstrated significantly reduced upward scapular rotation on both the dominant and non-dominant sides in all three planes. Patients with neck pain had increased internal rotation in the sagittal and frontal planes on the dominant side and increased external rotation in the frontal plane on the non-dominant side. No difference was observed between groups considering posterior scapular tilt.

INTERPRETATION

There are alterations in the 3-Dimensional scapular orientations in patients with chronic non-specific neck pain compared to healthy controls. Therefore, the scapular control may also be examined in patients with neck pain and it can be included in the rehabilitation program if needed.

Análise eletromiográfica de músculos do complexo do ombro durante exercícios de rotação externa com faixa elástica

RESUMO Na artrocinemática do ombro, o manguito rotador atua estabilizando a cabeça umeral em contato com a cavidade glenoidal, enquanto realiza a translação inferior para contrabalancear a força rotacional promovida principalmente pelo deltoide. Exercícios de rotação externa (RE) vêm sendo utilizados na reabilitação de pacientes com disfunções no complexo do ombro buscando restaurar a artrocinemática. Porém, poucos estudos abordam a utilização da faixa elástica e a avaliação dos músculos da cintura escapular, determinantes para uma cinemática adequada. O objetivo deste estudo é comparar a atividade eletromiográfica (EMG) de músculos do complexo do ombro durante exercícios de rotação externa com faixa elástica. Participaram 11 sujeitos do sexo masculino que foram avaliados durante os movimentos de (1) RE em ortostase; (2) RE com abdução de ombro; (3) RE em decúbito lateral (DL). Os músculos avaliados pela EMG foram: (1) trapézio superior (TS); (2) deltoide médio (DM); (3) deltoide posterior (DP); e (4) infraespinal (IN). A resistência foi determinada por uma faixa elástica cinza calibrada com carga de 5% do peso corporal. A análise dos dados foi realizada no software Biomec-SAS e as estatísticas foram calculadas por meio da Anova de medidas repetidas no software SPSS v20.0. Pôde-se constatar que os músculos TS e DM obtiveram maior atividade EMG durante o exercício de RE com abdução de ombro, o músculo DP durante a RE com abdução de ombro e RE em decúbito lateral, enquanto o IN a obteve durante a RE em ortostase e RE em decúbito lateral.

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.

Comparison of scapular position and upper extremity muscle strength in patients with and without lateral epicondylalgia: a case-control study

BACKGROUND

The symptoms of lateral epicondylalgia (LE) can be persistent, and recurrence is frequent. Recurrence can be related to proximal segment impairment of the kinetic chain. Knowledge of any relation in the kinetic chain in LE may help treatment. We aimed to investigate scapular position and upper extremity muscle strength in patients with LE and to compare them with controls.

METHODS

The study enrolled 51 patients with LE and 51 age-matched controls. We assessed scapular position asymmetry using the lateral scapular slide test and measured the strength of the upper trapezius (UT), middle trapezius (MT), lower trapezius, and serratus anterior muscles in addition to shoulder abduction, external rotation, and internal rotation and grip strength.

RESULTS

The percentage of participants with scapular asymmetry was greater in the patients than in the controls (P = .005). The involved side regarding shoulder external rotation among the patients was significantly weaker than in the controls (P = .016, P = .009). The involved side of the LE patients was significantly weaker than the uninvolved side in terms of shoulder abduction, external rotation, and internal rotation (P = .013, P = .048, P = .013). The UT/MT ratio on the nondominant side of the controls was significantly greater than that on the involved side of the LE patients (P = .016).

CONCLUSION

Upper extremity muscle strength, grip strength, UT/MT ratio, and scapular position are affected in patients with LE. In addition to the elbow, focusing on the upper segments is essential in the management of LE.

Progressive conscious control of scapular orientation with video feedback has improvement in muscle balance ratio in patients with scapular dyskinesis: a randomized controlled trial

BACKGROUND

Video feedback (VF) can guide patients to consciously control scapular orientation without inappropriate substitution. This study investigated whether progressive conscious control with VF improves scapular muscle activation and movements during arm elevation in patients with subacromial impingement and scapular dyskinesis.

METHODS

The study recruited 38 amateur overhead athletes with subacromial impingement and scapular medial border prominence who were randomly assigned to the VF or control group. The participants in both groups controlled the scapular position and progressively practiced from 0° to 45° and from 0° to 90° of arm elevation. Participants in the VF group also controlled the scapular position with a video presentation of the scapula on a screen. We investigated the scapular kinematics, muscle activation, and balance ratio for outcome collection in the preintervention and postintervention conditions with and without VF conditions.

RESULTS

Decreased upper trapezius (UT) activation (3%-13%, P < .0083), increased lower trapezius (LT) activation (3%-17%, P < .0083), restored UT/LT ratios (0.67-3.13, P < .0083), and decreased scapular internal rotation (1.8°-6.1°, P < .003) relative to the preintervention condition were demonstrated in the 2 postintervention conditions in both groups. The VF group also demonstrated decreased UT/serratus anterior ratios (0.21-0.30, P < .0083) in 2 postintervention conditions relative to the preintervention condition.

CONCLUSIONS

The progressive control of scapular orientation with or without VF can be used to reduce the UT/LT ratio and improve scapular internal rotation during arm elevation. Control training with VF can further decrease the UT/serratus anterior ratio.

A preliminary exploration of plain-film radiography in scapular dyskinesis evaluation

BACKGROUND

Evaluation of scapular dyskinesis is of clinical interest because it is believed to be associated with pathologies of the shoulder. This study investigated the feasibility of plain-film radiography in evaluating scapular dyskinesis.

METHODS

Subjects with unilateral disorders of the shoulder (n = 186) who underwent plain-film radiography of bilateral scapulae were divided into 4 categories of scapular dyskinesis patterns according to the Kibler classification and analyzed. Coracoid upward shift distance (CUSD), length of the scapular spine line (LSS), and scapular upward rotation angle (SURA) were measured on the radiographs. Intrarater and inter-rater reliability were tested, and the characteristics of these parameters in each type were analyzed. The differences (d) between bilateral scapulae (d-CUSD, d-LSS, and d-SURA) among the 4 categories were compared.

RESULTS

Intrarater and inter-rater reliability were excellent for all parameters. Significant differences between the scapulae were observed in CUSD in type I and in LSS in type II categories. No significant difference in any of the parameters was found in type III. Compared with the other categories, d-CUSD in type I and d-LSS in type II were significantly larger. The cutoff values of d-CUSD and d-LSS were 1.1 mm and 1.2 mm, respectively. No significant difference in d-SURA was found among the 4 categories.

CONCLUSIONS

The measurement of CUSD, LSS, and SURA on plain-film radiography had excellent reliability. d-CUSD and d-LSS were characteristic parameters of type I and type II, respectively; however, type III had no distinguishing characteristics among the parameters.

Scapular kinematic and shoulder muscle activity alterations after serratus anterior muscle fatigue

BACKGROUND

Although the serratus anterior muscle has an important role in scapular movement, no study to date has investigated the effect of serratus anterior fatigue on scapular kinematics and shoulder muscle activity. The purpose of this study was to clarify the effect of serratus anterior fatigue on scapular movement and shoulder muscle activity.

METHODS

The study participants were 16 healthy men. Electrical muscle stimulation was used to fatigue the serratus anterior muscle. Shoulder muscle strength and endurance, scapular movement, and muscle activity were measured before and after the fatigue task. The muscle activity of the serratus anterior, upper and lower trapezius, anterior and middle deltoid, and infraspinatus muscles was recorded, and the median power frequency of these muscles was calculated to examine the degree of muscle fatigue.

RESULTS

The muscle endurance and median power frequency of the serratus anterior muscle decreased after the fatigue tasks, whereas the muscle activities of the serratus anterior, upper trapezius, and infraspinatus muscles increased. External rotation of the scapula at the shoulder elevated position increased after the fatigue task.

CONCLUSION

Selective serratus anterior fatigue due to electric muscle stimulation decreased the serratus anterior endurance at the flexed shoulder position. Furthermore, the muscle activities of the serratus anterior, upper trapezius, and infraspinatus increased and the scapular external rotation was greater after serratus anterior fatigue. These results suggest that the rotator cuff and scapular muscle compensated to avoid the increase in internal rotation of the scapula caused by the dysfunction of the serratus anterior muscle.

Analysis of the kinetic chain in asymptomatic individuals with and without scapular dyskinesis

BACKGROUND

This study measured strength of the trunk and hip, and compared Y Balance Test and Upper Quarter Y Balance Test in individuals without and with scapular dyskinesis. Strength and endurance of the scapulothoracic muscles were also assessed.

METHODS

Forty-four individuals without shoulder pain were divided in 2 groups: without scapular dyskinesis (age 26.00, SD 4.10 years) and scapular dyskinesis (age 23.68, SD 4.20 years). Scapular dyskinesis was assessed by clinical observation of the scapular motion during arm elevation, and was classified as present or absent. A handheld dynamometer was used to measure the isometric strength of the trunk flexors and lateral flexors, hip extensors and abductors, lower trapezius, serratus anterior, and latissimus dorsi. Y and Upper Quarter Y Balance Tests were performed with the individual in single-limb and 3-point plank position, respectively. Endurance of the scapulothoracic muscles was assessed with the individuals in prone with the arm at 135° abduction. Independent t-test and Mann-Witney test were used for comparison between groups. A P < 0.05 was considered significant. Effect sizes between groups were also calculated.

FINDINGS

No differences (P > 0.05) were demonstrated between groups for all variables. Moderate effect size (d ~ 0.40) was found for the trunk flexors and hip extensors, and endurance of the scapulothoracic muscles, whereas the scapular dyskinesis group showed less strength and endurance in relation to the group without dyskinesis.

INTERPRETATION

Strength of the trunk flexors and hip extensors, and endurance of the scapulothoracic muscles seem to have influence in scapular dyskinesis in non-athletes without shoulder pain.

Scapular muscle dysfunction associated with subacromial pain syndrome

STUDY DESIGN

Narrative Review.

INTRODUCTION

One of the shoulder pain disorders in which the function of the scapula is comprised is the subacromial pain syndrome. Several rehabilitation guidelines and exercises have been proposed to improve scapulothoracic muscle dysfunction. Consideration of muscle activation patterns may help to select the most appropriate rehabilitation exercise in these patients. To date, suggesting rehabilitation exercises is often based upon the knowledge of the superficial lying scapulothoracic muscles' activity. In the assumption that the deeper lying scapulothoracic muscles' activity may hinder normal scapular movement in case of tightness or hyperactivity, exercise protocols for patients with altered pattern in scapulothoracic muscles should also integrate knowledge on the deeper lying scapulothoracic muscle activity.

PURPOSE OF THE STUDY

To help clinicians choosing the most appropriate exercise in patients with subacromial pain syndrome related to scapulothoracic muscle dysfunction.

METHODS

First, a summary of key alterations in scapulothoracic (muscle) function in patients with subacromial pain was accomplished. Second, promising practical rehabilitation strategies toward restoring scapulothoracic muscle dysfunction (with a focus on scapulothoracic exercises) were developed, integrating current new research evidence (including information about the deeper lying scapulothoracic muscles) with clinical practice.

CONCLUSION

This review details clinical exercises and their muscular activity to guide clinicians to optimize individualized scapulothoracic training and treatment programs by selecting the most appropriate exercise, based on knowledge from the clinical examination.

LEVEL OF EVIDENCE

Level 5.

Scapular Kinematics by Sex Across Elevation Planes

Scapular kinematics are important indicators of dyskinesis, often suggesting underlying shoulder pathology, but the influence of sex is unknown. This study's objective was to examine scapular kinematics in healthy males and females. Positions of surface-mounted reflective markers were tracked during arm elevation movements in 0°/30°/40°/60°/90°/120° planes. Scapulothoracic rotations (protraction/retraction, medial/lateral rotation, posterior/anterior tilt) were calculated. ANOVA analysis evaluated main and interaction effects of sex, plane, phase, and elevation angle. Males and females had similar protraction/retraction and medial/lateral rotation kinematics; mean sex-related peak angle differences were 2.5°, 1.8° (raise [concentric]), respectively, and 2.9°, 2.7° (lower [eccentric]), respectively. Largest sex differences for mean peak angle occurred for posterior/anterior tilt at higher elevation angles (raise, 8.4°; lower, 8.5°). Elevation, plane, and phase were main effects for all scapular rotations (P < .001). Sex was not a main effect for any rotations. Sex × elevation interactions influenced protraction/retraction (P < .001) and posterior/anterior tilt (P < .001). Sex × plane (P ≤ .01) and sex × phase (P ≤ .002) interactions influenced all rotations. Lower posterior tilt for females compared to males at higher elevation angles could relate to higher female shoulder pathology incidence. Sex, plane, and phase are necessary components of uninjured scapular kinematics. Sex-specific differences provide insight into potential shoulder pathology etiology. These data provide a benchmark to assess pathological populations.

Biomechanical analysis of the shoulder of swimmers after a maximal effort test

OBJECTIVES

To compare the kinematics and electromyography of the periscapular muscles in swimmers before and after a 3-min maximal effort test.

PARTICIPANTS

16 competitive swimmers.

MAIN OUTCOME MEASUREMENTS

Infrared cameras were used to record kinematics in the scapular plane in synchronization with the electromyography system.

RESULTS

There was an increase in internal rotation in all angles (p < 0.05), an increase of the anterior tilt, with 120° of elevation (p = 0.04). The serratus anterior showed a decrease in the intervals of 120-90° and 60-30° (p = 0.04; p = 0.02). There was a linear relationship between the variation before and after the maximal effort of the anterior tilt in relation to the variation of muscular activation of the transverse trapezius (p = 0.01) and the lower trapezius (42%, p = 0.01); an internal rotation in 120° and 90° of elevation in relation to the transverse trapezius (p = 0.01); and an internal rotation in 60° and 30° of elevation in relation to the serratus anterior (p = 0.04, p = 0.03).

CONCLUSION

A maximal 3-min effort test resulted in altered scapular biomechanics. More studies are needed to verify if the changes correspond to a risk factor for injuries.

Muscle activity of upper and lower trapezius and serratus anterior during unloaded and maximal loaded shoulder flexion and extension

Altered scapular muscle activity is mostly described under unloaded and submaximal loaded conditions in impingement patients. However, there is no clear evidence on muscle activity with respect to movement phases under maximum load in healthy subjects. Therefore, this study aimed to investigate scapular muscle activity under unloaded and maximum loaded isokinetic shoulder flexion and extension in regard to the movement phase. Fourteen adults performed unloaded (continuous passive motion [CPM]) as well as maximum loaded (concentric [CON], eccentric [ECC]) isokinetic shoulder flexion (Flex) and extension (Ext). Simultaneously, scapular muscle activity was measured by EMG. Root mean square was calculated for the whole ROM and four movement phases. Data were analyzed descriptively and by two-way repeated measures ANOVA. CPM_Flex resulted in a linear increase of muscle activity for all muscles. Muscle activity during CON_Flex and ECC_Flex resulted in either constant activity levels or in an initial increase followed by a plateau in the second half of movement. CPM_Ext decreased with the progression of movement, whereas CON_Ext and ECC_Ext initially decreased and either levelled off or increased in the second half of movement. Scapular muscle activity of unloaded shoulder flexion and extension changed under maximum load showing increased activity levels and an altered pattern over the course of movement.

The Effectiveness of Exercise Therapy on Scapular Position and Motion in Individuals With Scapular Dyskinesis: Systematic Review Protocol

Background

Scapular dyskinesis is an alteration in normal scapular position and motion. Some researchers believe that altered kinematics of the scapula subsequent to dysfunction or weakness of scapular stabilizing muscles contributes to impingement syndrome. Scapular muscle exercises are included in the rehabilitation of patients with subacromial impingement syndrome and scapular dyskinesis because the muscular system is one of the major contributors of scapular positioning both at rest and during shoulder movement, but there is considerable uncertainty relating to the relative effectiveness of such approaches on changing scapular position and motion.

Objective

The aim of this systematic review protocol is to evaluate the effectiveness of exercise therapy on scapular position and motion in individuals with scapular dyskinesis.

Methods

A systematic review will be conducted using PubMed, Scopus, Web of Science, Elsevier, Ovid, ProQuest, Physiotherapy Evidence Database, and Cochrane Library. The reference lists of articles, other reviews, gray literature, and key journals will be searched for relevant articles. Clinical trials reporting the effect of therapeutic exercises (scapular strengthening exercise, scapular stabilization exercise, scapular muscle stretching) with the aims of changing scapular position and motion in individuals with scapular dyskinesis will be included. Two independent reviewers will select studies, extract data, and assess the quality of primary studies. Any disagreement during the selection of studies will be discussed and decided by the whole team.

Results

This systematic review began in December 2016 and is currently in progress. The findings will be synthesized to determine the effectiveness of recommended therapeutic exercise on scapular position and motion in individuals with scapular dyskinesis.

Conclusions

This is the first systematic review protocol aiming to assess the effectiveness of exercise therapy in individuals with scapular dyskinesis. The systematic review doesn’t require ethics approval because all data used will be provided from published documents. The results of this study will be published in a peer-reviewed journal.

Trial Registration

PROSPERO CRD42017053923; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=53923 (Archived by WebCite at http://www.webcitation.org/6uzq32T02)

Measurement of scapular medial border and inferior angle prominence using a novel scapulometer: A reliability and validity study

BACKGROUND

Previous studies have proposed various ways to assess scapular dyskinesis. In clinic, assessment tools designed to measure the posterior displacement of the inferior angle of the scapula with reference to the posterior thoracic cage are needed.

OBJECTIVES

A novel scapulometer was developed to measure scapular medial border and inferior angle prominence.

METHODS

A novel scapulometer was designed to measure the distance from the root of the spine (ROS) and the inferior angle (INF) of the scapula to the thorax wall in 29 participants with scapular dyskinesis bilaterally. Two raters measured the ROS and INF distance of the scapula 3 times bilaterally. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were calculated to determine the inter-rater and intra-rater reliability. Validity was based on correlations (convergent: ROS and internal/external rotation, and INF and tilt; divergent: ROS/INF and upward rotation of the scapula) using a FASTRAK Polhemus 3-D motion tracking system assessing scapular tilt, internal/external rotation, and upward/downward rotation.

RESULTS

The average ROS and INF displacements were 13.7 ± 5.0 mm and 12.5 ± 6.3 mm, respectively. The results showed excellent intra-rater and inter-rater reliability, with ICC = 0.88-0.99 and 0.95-0.99 (SEM = 0.7-0.8 mm), respectively. Correlations were 0.35/0.19 (convergent validity) and 0.07/0.09 (divergent validity).

CONCLUSIONS

The novel scapulometer has excellent reliability and fair validity to quantify medial border and inferior angle prominence of the scapula. Further research utilizing this instrument is recommended.

The Effect of Shoulder Muscle Fatigue on Acromiohumeral Distance and Scapular Dyskinesis in Women With Generalized Joint Hypermobility

Muscle fatigue is considered to be one cause of shoulder pain, and subjects with generalized joint hypermobility (GJH) are affected more by shoulder pain. The purpose of this study was to examine the effects of muscle fatigue on acromiohumeral distance (AHD) and scapular dyskinesis in women with GJH. Thirty-six asymptomatic participants were assigned to either a GJH (n = 20) or control group (n = 16) using the Beighton scale. Before and after elevation fatigue trials, AHD was measured with ultrasonography at rest and when the arm was in 90° active elevation. A scapular dyskinesis test was used to visually observe alterations in scapular movement. Our results showed that in both groups, the fatigue reduced AHD in the 90° elevation position and increased the presence of scapular dyskinesis; however, no differences were found between the two groups. Although GJH has been identified as a factor for developing musculoskeletal disorders, generalized joint hypermobility did not result in changes to scapular dyskinesis or AHD, even after an elevation fatigue task. More studies are needed to evaluate the effects of muscle fatigue in subjects with GJH and a history of shoulder instability.

Intrarater and interrater reliability of three classifications for scapular dyskinesis in athletes

Clinical evaluation of scapular dyskinesis (SD) aims to identify abnormal scapulothoracic movement, underlying causal factors, and the potential relationship with shoulder symptoms. The literature proposes different methods of dynamic clinical evaluation of SD, but improved reliability and agreement values are needed. The present study aimed to evaluate the intrarater and interrater agreement and reliability of three SD classifications: 1) 4-type classification, 2) Yes/No classification, and 3) scapular dyskinesis test (SDT). Seventy-five young athletes, including 45 men and 30 women, were evaluated. Raters evaluated the SD based on the three methods during one series of 8-10 cycles (at least eight and maximum of ten) of forward flexion and abduction with an external load under the observation of two raters trained to diagnose SD. The evaluation protocol was repeated after 3 h for intrarater analysis. The agreement percentage was calculated by dividing the observed agreement by the total number of observations. Reliability was calculated using Cohen Kappa coefficient, with a 95% confidence interval (CI), defined by Kappa coefficient ±1.96 multiplied by the measurement standard error. The interrater analyses showed an agreement percentage between 80% and 95.9% and an almost perfect reliability (k>0.81) for the three classification methods in all the test conditions, except the 4-type and SDT classification methods, which had substantial reliability (k<0.80) in shoulder abduction. Intrarater analyses showed agreement percentages between 80.7% and 89.3% and substantial reliability (0.67 to 0.81) for both raters in the three classifications. CIs ranged from moderate to almost perfect categories. This indicates that the three SD classification methods investigated in this study showed high reliability values for both intrarater and interrater evaluation throughout a protocol that provided SD evaluation training of raters and included several repetitions of arm movements with external load during a live assessment.

Movement Pattern of Scapular Dyskinesis in Symptomatic Overhead Athletes

This study investigated the characteristics of arm elevation via principal component analysis in symptomatic overhead athletes with scapular dyskinesis. One hundred-thirty-four overhead athletes with scapular dyskinesis [24: inferior angle prominence (pattern I); 46: medial border prominence (pattern II), 64: pattern I + II] were evaluated by three-dimensional electromagnetic motion and electromyography to record the scapular kinematics (upward rotation/posterior tipping/exterior rotation) and muscle activation (upper trapezius: UT; middle trapezius: MT; lower trapezius: LT; serratus anterior: SA) during lowering phase of arm elevation. The results showed: (1) for pattern I and II, the first 3 principal component (PCs) explained 41.4% and 42.6% of total variance of movement; (2) the first PCs were correlated with MT, LT activity (r = 0.41~0.61) and upward rotation, posterior tipping (r = −0.59~−0.33) in pattern I, and UT, MT, SA (r = 0.30~0.70) activity in pattern II; (3) contour plots of muscle activity demonstrated that muscle activities varied with dyskinesis patterns. In summary, for the pattern I, the major characteristics are coactivation of MT and LT and corresponding scapular posterior tipping and upward rotation. For the pattern II, the major characteristics are coactivation of UT, MT and SA without corresponding scapular external rotation.

The scapula backward tipping test: An inter-rater reliability study

BACKGROUND & PURPOSE

The purpose of this study was to determine the reliability of the scapula backward tipping test (SBTT) in detecting the presence of pectoralis minor (PM) tightness and subsequently scapula forward tipping, in a symptomatic population. PM tightness with scapula forward tipping has been described to cause pain and dysfunction in the shoulder region.

METHODS

30 patients with a diagnosis of shoulder pain were randomly assigned and examined by 2 musculoskeletal physical therapists at a time. The procedure consisted of having the individual lay on the stomach in a neutral head position with palms in the anatomical position. The examiner firmly stabilized the inferior angle of the scapula with one hand and the fingers of the other hand hooked the under surface of the coracoid process. A gentle yet firm pull was imparted in an upward direction to sense tightness and to observe movement of the acromion up to the tragus of the ear. A comparison was made with the other side to sense restriction. Inter-rater reliability was determined using the kappa statistic.

RESULTS

The SBTT was found to be reproducible between examiners (Kappa = 0.735, SE of kappa = 0.123, 95% confidence interval), with a percentage agreement of 86.67%.

CONCLUSION

The SBTT may be incorporated as a simple yet effective test to determine the presence of PM tightness and subsequently scapula forward tipping.