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

Fatigue-related changes in intermuscular electromyographic coherence across rotator cuff and deltoid muscles in individuals with and without subacromial pain

Neuromuscular fatigue induces superior migration of the humeral head in individuals with subacromial pain. This has been attributed to weakness of rotator cuff muscles and overactive deltoid muscles. Investigation of common inputs to motoneuron pools of the rotator cuff and deltoid muscles offers valuable insight into the underlying mechanisms of neuromuscular control deficits associated with subacromial pain. This study aims to investigate intermuscular coherence across the rotator cuff and deltoid muscles during a sustained submaximal isometric fatiguing contraction in individuals with and without subacromial pain. Twenty symptomatic and 18 asymptomatic young adults participated in this study. Surface electromyogram (EMG) was recorded from the middle deltoid (MD) and infraspinatus (IS). Intramuscular EMG was recorded with fine-wire electrodes in the supraspinatus (SS). Participants performed an isometric fatiguing contraction of 30° scaption at 25% maximum voluntary contraction (MVC) until endurance limit. Pooled coherence of muscle pairs (SS-IS, SS-MD, IS-MD) in the 2-5 Hz (delta), 5-15 Hz (alpha), and 15-35 Hz (beta) frequency bands during the initial and final 30 s of the fatigue task were compared. SS-IS and SS-MD delta-band coherence increased with fatigue in the asymptomatic group but not the symptomatic group. In the alpha and beta bands, SS-IS and SS-MD coherence increased with fatigue in both groups. IS-MD beta-band coherence was greater in the symptomatic than the asymptomatic group. Individuals with subacromial pain failed to increase common drive across rotator cuff and deltoid muscles and have altered control strategies during neuromuscular fatigue. This may contribute to glenohumeral joint instability and subacromial pain experienced by these individuals.NEW & NOTEWORTHY Through the computation of shared neural drive across glenohumeral muscles, this study reveals that individuals with subacromial pain were unable to increase shared neural drive within the rotator cuff and across the supraspinatus and deltoid muscles during neuromuscular fatigue induced by sustained isometric contraction. These deficits in common drive across the shoulder muscles likely contribute to the joint instability and pain experienced by these individuals.

Efficacy of Targeted Scapular Stabilization Exercise Versus Conventional Exercise for Patients With Shoulder Pain: A Randomized Clinical Trial

OBJECTIVE

The aim of the study is to investigate the efficacy of targeted scapular stabilization exercise in shoulder pain.

DESIGN

This is an evaluator-blinded, multicenter, randomized controlled trial. The scapular stabilization exercise group ( n = 45) received scapular stabilization exercise based on the type of scapular dyskinesis for 6 wks; the conventional exercise group ( n = 45) received pendulum, wall climbing and stick exercises for 6 wks. Constant-Murley score, numerical rating scale, range of motion, type of scapular dyskinesis, lateral scapular sliding test, pectoralis minor index, scapular index, and satisfaction were assessed at baseline, 2-, 4-, and 6-wk treatment as well as a 6-wk follow-up.

RESULTS

After a 6-wk intervention, the improvement of Constant-Murley score was greater in the scapular stabilization exercise group than in the conventional exercise group, and improvement continued at the 6-wk follow-up ( F = 15.39, P < 0.001, partial η 2 = 0.17). The results were also significant for numerical rating scale during activity, lateral scapular sliding test, pectoralis minor index, type of scapular dyskinesis, and satisfaction in favor of the scapular stabilization exercise group ( P < 0.05).

CONCLUSIONS

Targeted scapular stabilization exercise is an effective intervention program that might be applied to the rehabilitation of shoulder pain.

Analysis of the three-dimensional scapular kinematics and associated scapular muscle activity during scapular muscle exercises

OBJECTIVE

To compare scapular kinematics and muscle activity among various scapular muscle exercises.

DESIGN

A cross-sectional study.

SETTING

A university research laboratory.

PARTICIPANTS

Eighteen healthy men participated in this study.

MAIN OUTCOME MEASURES

Three-dimensional scapular kinematics was measured with an electromagnetic motion capture system. Activities of the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) were measured by using surface electromyography (EMG). In addition, the ratio of LT to the UT (LT/UT) and SA to the UT (SA/UT) was calculated. A repeated one-way analysis of variance and Shaffer's post-hoc analysis were used to detect the differences in each outcome during five exercises.

RESULTS

The scapula was rotated upwardly during all exercises except push-up plus. The LT/UT ratio during side-lying external rotation and side-lying flexion were significantly higher than that for scapular plane elevation (P < .05), although the highest activity of the lower trapezius was produced during scapular plane elevation. The activities of the serratus anterior and SA/UT ratio during horizontal adducted elevation and push-up plus were significantly higher than that during scapular plane elevation (P < .05).

CONCLUSION

Horizontal adducted elevation might be more appropriate for increasing scapular upward rotation with high serratus anterior activity and SA/UT ratio than push-up plus.

Effects of manual therapy in addition to stretching and strengthening exercises to improve scapular range of motion, functional capacity and pain in patients with shoulder impingement syndrome: a randomized controlled trial

BACKGROUND

The current study aimed to measure the effectiveness of manual therapy in addition to stretching and strengthening exercises in patients with shoulder impingement syndrome to improve functional capacity, pain, and scapular range of motion.

METHODS

This is a single-blinded randomized controlled trial. Thirty-two participants with chronic shoulder impingement syndrome were randomly allocated into two groups. Both groups received stretching and strengthening exercises while the treatment group was given manual therapy additionally. Treatment was started after the patients signed an informed consent form. The data were collected from the University of Lahore Teaching Hospital between March 2022 and December 2022. The study aimed to measure pain using a numeric pain rating scale, functional capacity was assessed by the disability of the arm and shoulder, and goniometry was used for scapular ranges, i.e., scapular protraction and upward rotation. Each treatment session lasted 45 min for the treatment group and 30 min for the control group. The treatment comprised five days a week for four weeks, after which post-intervention measurements were taken.

RESULTS

Thirty-two participants were enrolled in the study, and 16 were divided into each group. The mean age of the participants in the treatment group was 38.19 ± 7.31 while the comparison group was 35.69 ± 7.98. An independent sample t-test was run on the data with a 95% confidence interval, statistically significant results were obtained, i.e., p-value < 0.05, post-intervention in the treatment group. Both groups have significantly improved functional capacity and scapular protraction (p < 0.005), however, pain and scapular upward rotation were not found statistically significant in the control group (p > 0.05).

CONCLUSION

The addition of manual therapy along with exercise therapy showed clinical and statistical significant results for pain, functional capacity, and scapular range of motion. It demonstrated superior effects than exercise therapy alone for the chronic condition of SIS.

TRIAL REGISTRATION

The trial was registered in the Iranian Registry of Clinical Trials ( https://www.irct.ir/ ) with the registration number: IRCT20230526058291N1, (Date: 12/08/2023).

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.

Exercises With Optimal Scapulothoracic Muscle Activation for Individuals With Paraplegia

Background

Individuals with paraplegia and coexisting trunk and postural control deficits rely on their upper extremities for function, which increases the risk of shoulder pain. A multifactorial etiology of shoulder pain includes "impingement" of the supraspinatus, infraspinatus, long head of the biceps tendons, and/or subacromial bursa resulting from anatomic abnormalities, intratendinous degeneration, and altered scapulothoracic kinematics and muscle activation. Targeting serratus anterior (SA) and lower trapezius (LT) activation during exercise, as part of a comprehensive plan, minimizes impingement risk by maintaining optimal shoulder alignment and kinematics during functional activities. To prevent excessive scapular upward translation, minimizing upper trapezius (UT) to SA and LT activation is also important.

Objectives

To determine which exercises (1) maximally activate SA and minimize UT:SA ratio and (2) maximally activate LT and minimize UT:LT ratio.

Methods

Kinematic and muscle activation data were captured from 10 individuals with paraplegia during four exercises: "T," scaption (sitting), dynamic hug, and SA punch (supine). Means and ratios were normalized by percent maximum voluntary isometric contraction (MVIC) for each muscle. One-way repeated measures analysis of variance determined significant differences in muscle activation between exercises.

Results

Exercises were rank ordered: (1) maximum SA activation: SA punch, scaption, dynamic hug, "T"; (2) maximum LT activation: "T," scaption, dynamic hug, SA punch; 3) minimum UT:SA ratio: SA punch, dynamic hug, scaption, "T"; and (4) minimum UT:LT ratio: SA punch, dynamic hug, "T," scaption. Exercise elicited statistically significant changes in percent MVIC and ratios. Post hoc analyses revealed multiple significant differences between exercises (p < .05).

Conclusion

SA punch produced the greatest SA activation and lowest ratios. Dynamic hug also produced optimal ratios, suggesting supine exercises minimize UT activation more effectively. To isolate SA activation, individuals with impaired trunk control may want to initiate strengthening exercises in supine. Participants maximally activated the LT, but they were not able to minimize UT while upright.

Ischemic compression associated with joint mobilization does not promote additional clinical effects in individuals with rotator cuff related shoulder pain: A randomized clinical trial

OBJECTIVE

The objective of this study was to verify which are the additional effects of the ischemic compression (IC) technique associated with joint mobilization techniques on pain, morphological aspects of myofascial trigger points (MTrPs), function, and psychological aspects in individuals with rotator cuff-related shoulder pain (RCRSP).

METHODS

Sixty individuals with RCRSP were randomly allocated intervention sessions the Mobilization Group (MG, n = 20), only joint mobilizations of the shoulder complex; intervention sessions Compression Group (CG, n = 20), with the same mobilizations associated with the IC over MTrPs; and Placebo Group (PG, n = 20), with the same mobilizations associated with placebo of IC. All interventions performed 2 per week, for 6-weeks. Pain was assessed by Visual Analogue Scale and function by the Disabilities of the Arm, Shoulder and Hand questionnaire. The kinesiophobia, pain catastrophizing, perception of improvement, mobility, pain threshold and area the MTrPs were also evaluated at baseline (week-0), after 6-weeks and after 10-weeks.

RESULTS

There were no between-group difference in pain: CG-MG 0.8 (95% CI 0.4 to 1.2), CG-PG 0.5 (95% CI 0.0 to 0.9), MG-PG -0.3 (95% CI -0.8 to 0.1) after 6-weeks and CG-MG 0.1 (95% CI -0.2 to 0.5), CG-PG -0.7 (95% CI -0.9 to -0,4), MG-PG -0,8 (95% CI -1.07 to 0.5) at 10-weeks. Similar effects were observed on function, characteristics of MTrPs and psychological aspects.

CONCLUSION

The IC technique on the MTrPs of the upper trapezius muscle associated with joint mobilization techniques has no additional effect on pain in individuals with RCRSP.

TRIAL REGISTRATION

RBR-44v8y7.

Specific versus general exercise programme in adults with subacromial impingement syndrome: a randomised controlled trial

Objectives

Current evidence on the clinical effectiveness about the different types of exercises in the subacromial impingement syndrome (SIS) remains controversial. This study aims to compare the short-term (at 5 weeks) effects of a specific exercise programme with a general exercise programme on shoulder function in adults with SIS.

Methods

In total, 52 adults with SIS were randomly allocated to 5 weeks to perform specific exercises (experimental group, n=26) or general exercises (control group, n=26). The primary outcome was change in shoulder function, it was assessed using the Shoulder Pain and Disability Index (SPADI) from baseline to 5 weeks. Secondary end points included changes in upper limb function (Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire), pain intensity (Visual Analog Scale (VAS)) and kinesiophobia (Tampa Scale of Kinesiophobia (TSK)).

Results

All participants completed the trial. The between-group differences at 5 weeks were: SPADI, 13.5 points (95% CI: 4.3 to 15.6; ƞ2=0.22; p=0.001); DASH, 10.1 points (95% CI: 5.6 to 15.2; ƞ2=0.27; p<0.001); VAS at rest, 0.2 cm (95% CI: 0.1 to 0.3; ƞ2=0.07; p=0.553); VAS on movement, 1.7 cm (95% CI: 0.9 to 2.2; ƞ2=0.24; p<0.001); and TSK, 16.3 points (95% CI: 13.2 to 15.3; ƞ2=0.33; p<0.001). All differences favoured the experimental group and effect sizes were medium to large for most outcomes. Mediation analyses showed that the effect of the specific exercises on shoulder function was mediated by kinesiophobia (β=2.800; 95% CI: 1.063 to 4.907) and pain on movement (β= -0.690; 95% CI: -1.176 to -0.271).

Conclusion

In adults with SIS, specific exercises may have a larger effect than general exercises. However, most differences did not reach the minimum threshold to be considered clinically important and the evidence to support exercise as standard treatment warrant further study.

Trial registration number

Brazilian Registry of Clinical Trials UTN number U111-1245-7878. Registered on 17 January 2020 (https://ensaiosclinicos.gov.br/rg/RBR-4d5zcg).

Scapular movement training is not superior to standardized exercises in the treatment of individuals with chronic shoulder pain and scapular dyskinesis: randomized controlled trial

PURPOSE

To investigate whether scapular movement training (SMT) is superior to standardized exercises in improving scapular biomechanics, behavioral, and clinical aspects of individuals with shoulder pain.

METHODS AND METHODS

A total of 64 individuals with chronic shoulder pain were randomly assigned to receive 16 sessions of SMT or SE over 8 weeks. Outcome measures included three-dimensional scapular kinematics, muscle activity of scapulothoracic muscles, pain, disability, fear-avoidance, kinesiophobia, and self-perceived changes. Kinematics and muscle activity were assessed at baseline and after treatment, and self-reported measurements at baseline, 4, 8, and 12 weeks.

RESULTS

SMT significantly (p < 0.05) decreased scapular internal rotation during arm elevation and lowering at sagittal and scapular planes (mean difference [MD]: ranged from 2.8 to 4.1°), and at lower angles of arm elevation and lowering at the frontal plane (MD: 3.4° and 2.4°, respectively), increased upper trapezius (UT) activity (MD: 10.3%) and decreased middle trapezius (MT) (MD: 60.4%) and serratus anterior (MD: 9.9%) activity during arm lowering compared to SE. Both groups significantly improved pain, disability, fear-avoidance, kinesiophobia, and self-perceived changes over 4 weeks, which was sustained over the remaining 8 weeks.

CONCLUSIONS

SMT is not superior to standardized exercises in improving scapular biomechanics, behavioral, and clinical aspects of individuals with shoulder pain.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03528499Implications for rehabilitationScapular movement training (SMT) showed small and likely not clinically relevant changes in scapular kinematics and muscle activity compared to standardized exercises.SMT and standardized exercises presented similar improvements in pain, disability, fear-avoidance beliefs, kinesiophobia, and self-perceived change in health condition immediately following 4-weeks of treatment, which was sustained over the following 8 weeks.The changes in patient-reported outcome measures are unlikely to be associated with changes in scapular kinematics and electromyographic activity.Clinicians should consider other factors than scapular movement during the treatment of patients with shoulder pain.

Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

Effectiveness of scapular mobilization in people with subacromial impingement syndrome: A randomized controlled trial

BACKGROUND

Scapular mobilization is a manual therapy technique widely used in the management of musculoskeletal disorders of the shoulder.

OBJECTIVE

To determine the effects of scapular mobilization in addition to an exercise program in people with subacromial impingement syndrome (SIS).

METHODS

Seventy-two adults with SIS were randomly allocated to 1 of 2 groups. The control group (n=36) participated in a 6-week exercise program, and the intervention group (n = 36) participated in the same exercise program plus passive manual scapular mobilization. Both groups were assessed at baseline and 6 weeks (end of treatment). The primary outcome measure was upper limb function assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Secondary outcome measures were the Constant-Murley questionnaire, pain (visual analog scale [VAS]), and scapular upward rotation.

RESULTS

All participants completed the trial. The between-group difference in DASH was -1.1 points (Cohen d = 0.05; p = 0.911), Constant-Murley 2.1 points (Cohen d = 0.08; p = 0.841), VAS rating of pain at rest -0.1 cm (Cohen d = 0.05; p = 0.684), and VAS rating of pain during movement -0.2 cm (Cohen d = 0.09; p = 0.764); scapular upward rotation at rest (arm by the side) was 0.6° (Cohen d = 0.09; p = 0.237), at 45° shoulder abduction was 0.8° (Cohen d = 0.13; p = 0.096), at 90° was 0.1° (Cohen d = 0.04; p = 0.783), and at 135° was 0.1° (Cohen d = 0.07; p = 0.886). Most differences were in favor of the intervention group; however, the effect sizes were weak and not statistically significant.

CONCLUSIONS

In the short-term, the addition of scapular mobilization did not provide significant clinical benefits in terms of function, pain or scapular motion in participants with SIS.

TRIAL REGISTRATION

Brazilian registry of clinical trials UTN number U1111-1226-2081. Registered February 25, 2019.

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.

Reliability of the scapular dyskinesis test yes-no classification in asymptomatic individuals between students and expert physical therapists

BACKGROUND

Scapular dyskinesis is considered a risk factor for the shoulder pain that may warrant screening for prevention. Clinicians of all experience screen scapular dyskinesis using the scapular dyskinesis test yes-no classification (Y-N), yet its reliability in asymptomatic individuals is unknown. We aimed to establish Y-N's intra- and inter-reliability between students and expert physical therapists.

METHODS

We utilized a cross-sectional design using consecutive asymptomatic subjects. Six students and two experts rated 100 subjects using the Y-N. Cohen's kappa (κ) and Krippendorff's alpha (K-α) were calculated to determine intra- and inter-rater reliability.

RESULTS

Intra- and inter-rater values for experts were κ=0.92 (95% confidence interval [CI], 0.91-0.93) and 0.85 (95% CI, 0.84-0.87) respectively; students were κ=0.77 (95% CI, 0.75-0.78) and K-α=0.63 (95% CI, 0.58-0.67).

CONCLUSIONS

The Y-N is reliable in detecting scapular dyskinesis in asymptomatic individuals regardless of experience.

Evidence for increased neuromuscular drive following spinal manipulation in individuals with subacromial pain syndrome

BACKGROUND

Thoracic spinal manipulation can improve pain and function in individuals with shoulder pain; however, the mechanisms underlying these benefits remain unclear. Here, we evaluated the effects of thoracic spinal manipulation on muscle activity, as alteration in muscle activity is a key impairment for those with shoulder pain. We also evaluated the relationship between changes in muscle activity and clinical outcomes, to characterize the meaningful context of a change in neuromuscular drive.

METHODS

Participants with shoulder pain related to subacromial pain syndrome (n = 28) received thoracic manipulation of low amplitude high velocity thrusts to the lower, middle and upper thoracic spine. Electromyographic muscle activity (trapezius-upper, middle, lower; serratus anterior; deltoid; infraspinatus) and shoulder pain (11-point scale) was collected pre and post-manipulation during arm elevation, and normalized to a reference contraction. Clinical benefits were assessed using the Pennsylvania Shoulder Score (Penn) at baseline and 2-3 days post-intervention.

FINDINGS

A significant increase in muscle activity was observed during arm ascent (p = 0.002). Using backward stepwise regression analysis, a specific increase in the serratus anterior muscle activity during arm elevation explained improved Penn scores following post-manipulation (p < 0.05).

INTERPRETATION

Thoracic spinal manipulation immediately increases neuromuscular drive. In addition, increased serratus anterior muscle activity, a key muscle for scapular motion, is associated with short-term improvements in shoulder clinical outcomes.

Changes in shoulder outcomes using ultrasonographic assessment of breast cancer survivors: a prospective longitudinal study with 6-month follow-up

This study aimed to describe changes in supraspinatus tendon thickness, acromiohumeral distance, and the presence of fluid in the subacromial bursa as measured by ultrasound, as well as shoulder range of motion and strength, perceived shoulder disability, and health-related quality of life in women before and after breast cancer treatment. Women who underwent surgery for unilateral breast cancer who did not suffer from shoulder pain or difficulty performing activities of daily living in the 6 months prior to surgery were included. One pre-surgical (A0) and three post-surgical assessments at 7-10 days (A1), 3 months (A2), and 6 months (A3) after surgery were carried out. The thickness of the supraspinatus tendon on the affected side decreased between post-surgical (A1) and 6-month (A3) follow-up assessments (p = 0.029), although the minimal detectable change was not reached. The active range of motion of the affected shoulder decreased after surgery. Strength changes were observed in both shoulders after surgery. The intensity of shoulder pain increased between post-surgical and 6-month follow-up assessments. Shoulder function was decreased at the post-surgical assessment and increased throughout the follow-ups. Health-related quality of life declined after surgery. A trend of decreasing thickness of the supraspinatus tendon of the affected shoulder was observed. Detecting these possible structural changes early would allow for early or preventive treatment.

Rehabilitative ultrasound imaging of the levator scapula muscle at rest and during contraction: Technical description and reliability

BACKGROUND

Altered scapular muscle activity is associated with abnormal scapular motions and shoulder pain. Hence, quantification of these activities is a challenging issue.

OBJECTIVES

The purposes of this study were to establish the reliability of measuring levator scapula muscle thickness and to examine how thickness of this muscle changes with contraction.

METHODS

Twenty-one asymptomatic individuals (mean age 22.29 ± 2.17 years) participated in this study. Three separate ultrasound images of the levator scapula muscle were captured at the neck-shoulder junction at rest and during a loaded isometric contraction. The procedures were repeated twice, four to seven days apart to establish intra-rater test-retest reliability. Interclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine the reliability, and a paired t-test was performed to examine the difference in muscle thickness between two conditions.

RESULTS

The results demonstrated that intra-examiner reliability was good at rest (ICC = 0.88, SEM = 1.16 mm) and excellent during loaded isometric contraction (ICC = 0.95, SEM = 0.91 mm). Furthermore, the thickness of levator scapula muscle significantly increased from rest to the loaded isometric contraction (Effect size = 1.99, P < 0.001).

CONCLUSION

This study demonstrates that the thickness of the levator scapula muscle can be measured reliably at the neck-shoulder junction. Furthermore, ultrasound measures can reliably detect changes in muscle thickness from rest to a contracted state. Therefore, if the need exists to evaluate muscle morphology before and after any treatment strategy, thickness measurement of levator scapula can be determined reliably using ultrasound.

Overhead Shoulder Position Versus Scapular Retraction Position to Normalize the Electromyographic Signal of the Lower Trapezius Muscle

This study aimed to compare electromyographic response of the lower trapezius muscle during maximal voluntary isometric contractions under two conditions: overhead shoulder position versus scapular position, rating the pain after each condition. Twenty-six participants with shoulder pain (SP; n = 15; Shoulder Pain and Disability Index-Pain = 34 [range 6-66]) and without shoulder pain (nSP; n = 11; Shoulder Pain and Disability Index-Pain = 0 [range 0-14]) performed maximal voluntary isometric contractions in those 2 conditions while the lower trapezius was monitored using surface electromyography. Pain was rated using the visual analog scale. The nSP group experienced no pain, whereas the SP group reported pain in both conditions with higher pain during the overhead movement. No differences were observed for muscle excitation between conditions, but higher levels were observed for the nSP group compared with the SP group. The overhead condition was more painful for the SP group (visual analog scale: SP = 4 vs nSP = 1.09, P = .036). Scapular position showed the same levels of LT excitation than overhead position. The scapular position is preferable, compared with overhead positioning, to normalize the lower trapezius instead of overhead positioning.

Bending the Elbow During Shoulder Flexion Facilitates Greater Scapular Upward Rotation and a More Favorable Scapular Muscle Activation Pattern

CONTEXT

Decreased scapular upward rotation (UR) and diminished activation of the serratus anterior (SA) and lower trapezius (LT) are often observed among patients with subacromial impingement syndrome. Maintaining the elbow fully flexed during shoulder flexion may limit glenohumeral motion due to passive insufficiency of the triceps brachii and therefore facilitate greater scapular UR and increased scapular muscle activation.

OBJECTIVES

To compare scapular UR, SA, upper trapezius (UT), middle trapezius, and LT activation levels between shoulder flexion with the elbow extended (Flexion-EE) to shoulder flexion with the elbow fully flexed (Flexion-EF). This study hypothesized that Flexion-EF would result in greater scapular UR, greater SA and LT activation, and a lower UT/SA and UT/LT activation ratio compared with Flexion-EE.

DESIGN

Cross-sectional study.

SETTING

A clinical biomechanics laboratory.

PARTICIPANTS

Twenty-two healthy individuals.

MAIN OUTCOME MEASURES

Scapular UR and electromyography signal of the SA, UT, middle trapezius, and LT, as well as UT/SA and UT/LT activation ratio were measured during Flexion-EE and Flexion-EF.

RESULTS

Flexion-EF resulted in greater scapular UR compared with Flexion-EE (P < .001). Flexion-EF resulted in greater SA activation, lower UT activation, and a lower UT/SA activation ratio compared with Flexion-EE (P < .001).

CONCLUSIONS

Fully flexing the elbow during shoulder flexion leads to increased scapular UR primarily through greater activation of the SA. This exercise may be of value in circumstances involving diminished scapular UR, decreased activation of the SA, and an overly active UT such as among patients with subacromial impingement syndrome.

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.

Scapular Retraction under Adduction Load: An Alternative to Overhead Exercises to Activate Infraspinatus, Upper, and Lower Trapezius in Subjects with and without Shoulder Pain

Exercises for lower trapezius (LT) often use overhead positions, causing compressive forces to the subacromial space. Scapular retraction would be an alternative to activate LT muscle. The present study aimed to assess the excitation levels of infraspinatus, upper trapezius, and lower trapezius muscles during a scapular retraction exercise under progressive adduction loads in subjects with and without painful shoulder. Electromyography of infraspinatus (IS), upper trapezius (UT), and LT was recorded during scapular retraction under progressive adduction loads of 42 participants, divided into two groups: with (SP, n = 26) and without shoulder pain (nSP, n = 16). The adduction loads of 20%, 30%, 40%, and 50% of the maximal voluntary contraction (MVC) were applied using a load cell. Normalized electromyography and the ratio between UT and LT (UT:LT) were used for statistical analysis. No differences were observed between groups, but a condition effect occurred for all muscles: UT showed higher values at 50% vs. 20% of MVC (p = 0.004); LT showed higher values on 40% and 50% of MVC (p = 0.001; 0.006). Higher values for IS were noted at 40% of MVC (vs. 20% of MVC; p = 0.04) and at 50% of MVC (vs. 20% of MVC; p = 0.001, vs. 30% of MVC, p = 0.001; vs. 40% of MVC; p = 0.001). UT:LT showed lower values at 50% of MVC (vs. 20% of MVC; p = 0.001 and vs. 30% of MVC; p = 0.016). Scapular retraction with adduction loads at 40-50% is an alternative to overhead exercises aiming to activate the LT and the IS muscles. The exercise ensures higher levels of LT and IS excitation without increasing UT excitation.

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.

Ischemic Pressure vs Postisometric Relaxation for Treatment of Rhomboid Latent Myofascial Trigger Points: A Randomized, Blinded Clinical Trial

OBJECTIVE

The purpose of this study was to investigate the effects of ischemic pressure (IP) vs postisometric relaxation (PIR) on rhomboid-muscle latent trigger points (LTrPs).

METHODS

Forty-five participants with rhomboid-muscle LTrPs were randomly assigned into 3 groups and received 3 weeks of treatment-group A: IP and traditional treatment (infrared radiation, ultrasonic therapy, and transcutaneous electrical nerve stimulation); group B: PIR and traditional treatment; and group C: traditional treatment. Shoulder pain and disability, neck pain and disability, and pressure pain threshold (PPT) of 3 points on each side were measured before and after treatment.

RESULTS

Multivariate analysis of variance indicated a statistically significant Group × Time interaction (P = .005). The PPT for the right lower point was increased in group A more than in groups B or C. Neck pain was reduced in group B more than in group C. Moreover, shoulder and neck disability were reduced in both groups A and B more than in group C. The PPTs of the left lower and middle points were increased in group B compared with groups A and C. The PPT of the left upper point was increased in group A more than in group C. There were significant changes in all outcomes in the 2 experimental groups (P < .05). No changes were found in the control group except in pain intensity, shoulder disability, and PPT of the left lower point.

CONCLUSION

This study found that IP may be more effective than PIR regarding PPT, but both techniques showed changes in the treatment of rhomboid-muscle LTrPs.

Short- and Long-Term Effects of a Scapular-Focused Exercise Protocol for Patients with Shoulder Dysfunctions-A Prospective Cohort

Current clinical practice lacks consistent evidence in the management of scapular dyskinesis. This study aims to determine the short- and long-term effects of a scapular-focused exercise protocol facilitated by real-time electromyographic biofeedback (EMGBF) on pain and function, in individuals with rotator cuff related pain syndrome (RCS) and anterior shoulder instability (ASI). One-hundred and eighty-three patients were divided into two groups (n = 117 RCS and n = 66 ASI) and guided through a structured exercise protocol, focusing on scapular dynamic control. Values of pain and function (shoulder pain and disability index (SPADI) questionnaire, complemented by the numeric pain rating scale (NPRS) and disabilities of the arm, shoulder, and hand (DASH) questionnaire) were assessed at the initial, 4-week, and 2-year follow-up and compared within and between. There were significant differences in pain and function improvement between the initial and 4-week assessments. There were no differences in the values of DASH 1st part and SPADI between the 4-week and 2-year follow-up. There were no differences between groups at the baseline and long-term, except for DASH 1st part and SPADI (p < 0.05). Only 29 patients (15.8%) had a recurrence episode at follow-up. These results provide valuable information on the positive results of the protocol in the short- and long-term.

EMG activity of the serratus anterior and trapezius muscles during elevation and PUSH UP exercises

BACKGROUND

Elevation and push up (Pu) exercises are considered to be beneficial for the rehabilitation of shoulder complex pathology. Despite their clinical utility, there is a lack of evidence comparing scapulothoracic muscles recruitment during these exercises.

OBJECTIVE

To evaluate the EMG activity of upper trapezius (UT), Lower Trapezius (LT), Upper Serratus anterior (USa) and Lower Serratus anterior (LSa) muscles during a variety of elevation and Pu exercises.

METHODS

Thirteen healthy participants (non, athlete, male, mean ± standard deviation; age: 21.1 ± 1.8 years; height: 1.80 m ± 0.04; weight: 79 ± 12 kg) were assessed. EMG data was collected during Scaption, wall slide and elevation with external rotation (EleEr) with and without load. Pu classic, Pu plus (PuP) on stable/unstable surfaces and Pu with shoulder internal rotation were also assessed.

RESULTS

UT had a significant higher activity during 'Scaption load' (p < .05) and LT in 'EleEr load' and 'Scaption load' (p < .05). USa and LSa had a significant higher activity on 'PuP unstable surface' and 'PuP internal rotation' compared to elevation exercises (p < .05). Scaption had greater activity ratio compared to the other exercises on UT/LT (p < .05). Pu variations had lower results in UT/USa and UT/LSa ratios compared to shoulder elevation exercises (p < .05).

CONCLUSIONS

Elevation exercises produce significant effects on upper and lower trapezius activation while Pu exercises on Sa muscles. Wall slide exercise notes the lowest activation in all muscles. A descending order of muscle activity during different variations of elevation and Pu exercises is provided in order to guide exercise selection in everyday clinical practice.

The Addition of Real-time Ultrasound Visual Feedback to Manual Facilitation Increases Serratus Anterior Activation in Adults With Painful Shoulders: A Randomized Crossover Trial

OBJECTIVE

Serratus anterior (SA) muscle activation may be decreased with subacromial pain syndrome. The purpose of this study was to determine whether the addition of real-time ultrasound (RTUS) visual feedback increased activation of SA in adults with painful shoulders in comparison to manual facilitation alone.

METHODS

This assessor-blinded, 2-period, randomized cross-over trial was conducted in a university medical imaging laboratory. Adults with mild-moderate unilateral subacromial pain received both interventions in random order with at least 1-week washout between interventions. Fourteen participants were randomized to receive manual facilitation with RTUS first, and 13 were randomized to receive manual facilitation alone first. Fifteen repetitions of a supine ``serratus punch'' were facilitated by RTUS visual feedback with manual facilitation or by manual facilitation alone. Levels of SA activation via surface electromyography were normalized to a maximum voluntary isometric contraction.

RESULTS

A total of 25 participants completed the full trial of both interventions. Data from 25 participant periods for RTUS with manual facilitation and data from 26 participant periods for manual facilitation only were analyzed. The predicted marginal mean difference between interventions was 55.5% (95% CI = 13.9% to 97.1%) in favor of the addition of RTUS feedback. No adverse effects occurred.

CONCLUSION

RTUS visual feedback increases SA activation in adults with painful shoulders compared with manual facilitation alone.

IMPACT

Determining if RTUS can improve SA muscle activation may help clinicians improve physical therapist interventions for subacromial pain syndrome.

Scapular movement training versus standardized exercises for individuals with chronic shoulder pain: protocol for a randomized controlled trial

BACKGROUND

Scapular focused exercise interventions are frequently used to treat individuals with shoulder pain. However, evidence for changes in scapular motion after intervention is limited.

OBJECTIVE

To compare the effects of scapular movement training versus standardized exercises for individuals with shoulder pain.

METHODS

This will be a single-blinded randomized controlled trial. Sixty-four individuals with shoulder pain for at least 3 months, scapular dyskinesis, and a positive scapular assistance test will be randomly allocated to one of two groups: Scapular Movement Training (group 1) and Standardized Exercises (group 2). Group 1 will receive education about scapular position and movement, and be trained to modify the scapular movement pattern. Group 2 will perform stretching and strengthening exercises. Both groups will be treated twice a week for eight weeks. Three-dimensional scapular kinematics and muscle activity of the serratus anterior and upper, middle, and lower trapezius during elevation and lowering of the arm will be assessed at baseline and after 8 weeks of treatment. Pain intensity, function, fear avoidance beliefs, and kinesiophobia will be assessed at baseline and after 4 and 8 weeks of treatment, and 4 weeks after the end of treatment.

CONCLUSIONS

The results of this study may contribute to a better understanding of the efficacy of scapular focused treatments for individuals with shoulder pain.

CLINICAL TRIAL REGISTRATION

NCT03528499.

Effects of electromyographic biofeedback interventions for shoulder pain and function: Systematic review and meta-analysis

OBJECTIVE

To systematically review the effectiveness of electromyographic biofeedback interventions to improve pain and function of patients with shoulder pain.

DESIGN

Systematic review of controlled clinical trials.

LITERATURE SEARCH

Databases (Medline, EMBASE, CINAHL, PEDro, CENTRAL, Web of Science, and SCOPUS) were searched in December 2020.

STUDY SELECTION CRITERIA

Randomized clinical trials that investigated the effects of electromyographic biofeedback for individuals with shoulder pain. Patient-reported pain and functional outcomes were collected and synthesized.

DATA SYNTHESIS

The level of evidence was synthesized using GRADE and Standardized Mean Differences and 95% confidence interval were calculated using a random-effects inverse variance model for meta-analysis.

RESULTS

Five studies were included with a total sample of 272 individuals with shoulder pain. Very-low quality of evidence indicated that electromyographic biofeedback was not superior to control for reducing shoulder pain (standardized mean differences = -0.21, 95% confidence interval: -0.67 to 0.24, P = 0.36). Very-low quality of evidence indicated that electromyographic biofeedback interventions were not superior to control for improving shoulder function (standardized mean differences = -0.11, 95% confidence interval: -0.41 to 0.19, P = 0.48).

CONCLUSION

Electromyographic biofeedback may be not effective for improving shoulder pain and function. However, the limited number of included studies and very low quality of evidence does not support a definitive recommendation about the effectiveness of electromyographic biofeedback to treat individuals with shoulder pain.

Comparison between dry needling plus manual therapy with manual therapy alone on pain and function in overhead athletes with scapular dyskinesia: A randomized clinical trial

Muscles' trigger points can induce scapular dyskinesia (SD) which interferes with overhead athletes' professional training. We aimed to evaluate effects of dry needling (DN) alone and plus manual therapy (MT) on pain and function of overhead athletes with SD. 40 overhead athletes (15 male, 25 female) aged 18-45 with at least 3 points Numeric Rating Scale (NRS) pain intensity during training were recruited and randomly allocated to the treatment group: MT followed by DN on trigger points of Subscapularis, Pectoralis minor, Serratus anterior, upper and lower Trapezius muscles; or the control group: MT alone. The effect of shoulder trigger points DN plus MT with MT alone on pain, function, Pain Pressure Threshold (PPT) and SD in athletes with SD were compared. Both the examiner and the therapist were blinded to group assignment. Both groups were analyzed. Pain, disability and SD were improved in treatment group (P < .05). On the other hand, when only MT was applied, despite reduction in pain and disability (P < .001), scapular slide only improved in hands on waist position. Comparing the differences between groups showed a substantial reduction in pain (P < .001) and disability (P = .02) with significant improvement in scapular dyskinesia in treatment group (P = .02). Moreover, PPT significantly increased in the control group (P = .004). No adverse effects reported by the participants during this study. DN is an easy and applicable method that can synergistically reduce pain, disability and dyskinesia when it is combined with manual techniques to treat shoulder dysfunctions.

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.

An electromyographic and kinematic study of the scapular stabilisers

Background

The scapular stabilisers, especially the actions of the force couples around the scapula, have an impact on the biomechanics of the scapula and the orientation of the glenoid.

Objectives

The aim of our study was to determine both the muscle activity and the correlation between the muscle activity ratio of the lower force couple (the serratus anterior lower fibres and the lower trapezius).

Methods

This was a quantitative cross-sectional study. Muscle activity of the dominant serratus anterior lower fibres and the lower trapezius muscles was collected with surface electromyographic (EMG) sensors and an inertial motion capture system was used to measure the three-dimensional (3D) shoulder flexion in the sagittal plane and abduction in the frontal plane. Graph Pad 5 (Prism, San Diego, CA, USA) was used for the statistical analysis. The confidence level was set at 95% (p < 0.05).

Results

Sixteen men and women participated in our study, with a mean (standard deviation) age of 25.4 (± 4.6) years, weight of 80.2 (± 25.1) kg and height of 171.6 (± 10.3) cm. A strong negative correlation was found at the start of the abduction (r = −0.623; p = 0.01) between the muscle activity of the serratus anterior lower fibres and the lower trapezius.

Conclusions

The only significant increase in the mean EMG ratio of serratus anterior lower fibres versus the lower trapezius was present at 60% (from baseline) of abduction (p = 0.03).

Clinical implications

The EMG activity ratio of serratus anterior lower fibres and lower trapezius remains variable in different movement planes.

Scapular movement impairments in individuals with subacromial pain syndrome based on scapular assistance test and scapula reposition test outcomes

BACKGROUND

Individuals with subacromial pain present with a variety of contributing impairments related to the movement problem. The scapular assistance test (SAT) and scapula reposition test (SRT) are proposed to identify shoulder pain related to abnormal scapular movement or position. It remains unknown if scapular movement related impairments are present in those with positive tests.

OBJECTIVES

To determine if scapular motion related impairments differ based on the result of the SAT or SRT in individuals with subacromial pain syndrome.

DESIGN

Cross-sectional METHOD: Sixty individuals with subacromial pain syndrome were included. Prior to obtaining results of the SAT and SRT, a single examiner measured scapular upward rotation and posterior tilt active and passive motion, pectoralis minor length, and strength of the middle trapezius, lower trapezius, and serratus anterior. Dynamic scapular motion was qualitatively assessed with the Scapular Dyskinesis Test. The Mann-Whitney U test assessed for differences based on the outcome of the SAT and SRT.

RESULTS

There was a significant difference (P = .023) in pectoralis minor length for the SAT. Participants with a positive SAT had decreased muscle length compared to those who tested negative. There were no significant differences in scapular motion or strength based on the result of either the SAT or SRT.

CONCLUSIONS

A positive SAT was associated with greater pectoralis minor length impairment, but not muscle strength or mobility. The SRT did not identify greater impairments in any of the scapular movement related impairments assessed. Individuals may vary in contributing impairments related to SAT or SRT results.

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.

Motor control integrated into muscle strengthening exercises has more effects on scapular muscle activities and joint range of motion before initiation of radiotherapy in oral cancer survivors with neck dissection: A randomized controlled trial

Background

Accessory nerve shoulder dysfunction is common after neck dissection in oral cancer survivors. This study aimed to investigate the short-term effects of scapular muscle strengthening exercises with motor-control techniques on neck dissection-related shoulder dysfunction in oral cancer survivors before the initiation of radiotherapy.

Methods

Thirty-eight participants were randomly allocated into the motor-control and regular-exercise groups. Each group received conventional physical therapy and specific scapular muscle strengthening exercises for 1 month immediately after neck dissection. Motor control techniques were integrated with scapular strengthening exercises for the motor-control group. Shoulder pain, active range of motion (AROM) of shoulder abduction, and scapular muscle activities including upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) when performing maximal voluntary isometric contraction (MVIC) and scapular muscle exercises were evaluated at baseline and after 1 month of training.

Results

Both groups reduced shoulder pain and increased muscle activity of maximum voluntary isometric contraction (MVIC) of each muscle after the intervention. Increased AROM of shoulder abduction was only observed in the motor-control group (95% CI 3.80 to 20.51, p = 0.004). Relative to baseline evaluation, muscle activities of UT decreased in the motor-control group when performing shoulder shrug with 1-kg weight (95% CI -33.06 to -1.29, p = 0.034). Moreover, the SA activity decreased in the motor-control group (95% CI -29.73 to -27.68, p<0.001) but increased in the regular-exercise group (95% CI 28.16 to 30.05, p<0.001) when performing shoulder horizontal adduction and flexion.

Conclusion

Early strengthening exercise with motor control techniques has greater benefits for improving AROM of shoulder abduction, muscle economy, and reducing compensatory scapular muscle activities in patients with neck dissection-related shoulder dysfunction before the initiation of radiotherapy.

Electromyographic Analysis of Shoulder Neuromuscular Activity in Women Following Breast Cancer Treatment: A Cross-Sectional Descriptive Study

Certain secondary effects derived from medical treatment in breast cancer can favor the development of alterations in shoulder biomechanics. To the best of our knowledge, persistent peripheral pain as a key factor for the development of neuromuscular activity impairments has not been analyzed. A cross-sectional descriptive study was carried out. A total of 90 women were included and allocated to three groups: (i) 30 women with persistent peripheral pain after breast cancer treatment, (ii) 30 women without pain after breast cancer treatment, and (iii) 30 healthy women. Surface electromyography was employed to measure the onset and amplitude of the muscle activity of three shoulder movements. Statistically significant differences were found in the neuromuscular activity for all the muscles and shoulder movements among women with persistent pain versus healthy women (i.e., amplitude muscle activity variable p < 0.001). Statistically significant differences were also observed in the neuromuscular activity for certain muscles in shoulder movements among women with persistent pain versus women without pain, as well as between women without pain versus healthy women. Therefore, following breast cancer treatment, women showed alterations in their shoulder neuromuscular activity, which were more significant if persistent pain existed. These findings may contribute to developing a selective therapeutic exercise program that optimizes the shoulder neuromuscular activity in women after breast cancer treatment.

Electromyographic biofeedback improves upper extremity function: a randomized, single-blinded, controlled trial

OBJECTIVE

To examine the effects of a 6-week surface electromyographic biofeedback intervention on the re-learning of upper extremity motor function in subjects with paretic upper extremity after stroke.

DESIGN

A randomized controlled trial.

SETTING

State Centre of Attention to Brain Injury, Madrid, Spain.

PARTICIPANTS

Thirty-eight participants in the sub-acute post-stroke stage were recruited and randomly allocated into either the surface electromyographic biofeedback (sEMG-BFB) or sham biofeedback (BFB) groups.

INTERVENTIONS

The sEMG-BFB group (n=19) received the intervention focused on re-learning scapulothoracic control during arm-reaching tasks involving shoulder abduction. The sham BFB group (n=19) received a sham intervention.

OUTCOME MEASURES

Upper extremity motor function assessed using the Fugl-Meyer Assessment-Upper Extremity Scale (66 points), the glenohumeral active range of motion, and the electromyographic amplitude signal of the middle deltoid and upper trapezius muscles were collected at baseline, after the intervention, and at the one-month follow-up.

RESULTS

Compared with the sham BFB group, the sEMG-BFB group experienced significant increases in upper extremity motor function after the intervention. The mean differences between groups were as follows: 4.79 points (95% CI 2.92 to 6.66) after the intervention; 6.55 points (95% CI 3.75 to 9.34) at the one-month follow-up; improved active range of motion 15.75 points (95% CI 6 to 30) after the intervention and electromyographic activity in the upper trapezius muscle changed in favour of the sEMG-BFB.

CONCLUSIONS

In the short term, a 6-week sEMG-BFB intervention effectively improved paretic upper limb motor function. Future research is needed to determine if the sEMG-BFB intervention has any long-term effects. Clinical trial number registration: NCT02974465 (ClinicalTrials.gov).

The immediate effects of passive joint mobilisation on local muscle function. A systematic review of the literature

BACKGROUND

Passive joint mobilisation is popular among healthcare providers and their patients; however, its effectiveness for improving muscle function is not well researched and the mechanisms of action involved are unclear.

OBJECTIVES

To assess the effect of passive joint mobilisations on the function of muscles surrounding the targeted joints in symptomatic as well as asymptomatic individuals.

SELECTION CRITERIA

Controlled experimental trials assessing the immediate effect of passive joint mobilisation on outcomes associated with local muscle function.

DATA COLLECTION

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

A total of seventeen studies were included, of which ten studies reported data on asymptomatic individuals and seven studies reported data on symptomatic individuals with various conditions. There is a moderate level of evidence that joint mobilisation immediately decreases the activation of superficial muscles during low load conditions in symptomatic individuals. For asymptomatic individuals, there is a low level of evidence that passive joint mobilisation improves maximum muscle strength when compared to sham mobilisation, opposed to a very low level of evidence suggesting no effect in symptomatic individuals. The five studies reporting data on both, changes in muscle function as well as changes in pain, suggest that other, not pain-related mechanisms may play an important role regarding the reported improvement in muscle function.

CONCLUSION

Current best evidence suggests that passive joint mobilisation has the ability to immediately alter muscle function. The specific mechanisms of action involved require further basic science investigations. Registration number (PROSPERO): CRD42018117033.

Effect of the Triceps Brachii Facilitation Technique on Scapulohumeral Muscle Activation during Reach and Point in a Healthy Population

Purpose: Neurodevelopmental techniques are commonly used in upper limb rehabilitation, but little evidence supports the facilitation techniques associated with this concept. This exploratory study determined whether a facilitation technique at the triceps muscle affected scapulothoracic muscle activity during reach in healthy participants compared with self-selected posture and reach. The secondary aim was to determine whether muscle activation levels differed between the facilitation technique and the optimized posture or guided movement. We also hypothesized that activity in the scapular stabilizers (lower trapezius [LT] and serratus anterior [SA]) would be increased during the facilitated movement than in the other conditions. Methods: The study included 17 healthy participants (aged 20-70 y). Surface electromyography recorded muscle activity in the upper trapezius (UT), middle trapezius (MT), and LT muscles and in the SA, middle deltoid (MD), and triceps during five performance conditions. We used Friedman's test to explore differences in muscle activity across conditions and Bonferroni's post hoc test to explore the differences between conditions. Results: The facilitation technique produced decreased activity in the SA, MD, and triceps muscles (p < 0.01) compared with the self-executed control condition. Compared with optimized posture with independent reach, facilitated movement again produced similar reductions in MD and triceps activity, with decreased LT activity also noted (p < 0.01). Lower activity levels were noted during facilitation than during manual guidance, with or without optimized posture, in the UT, MT, (p < 0.01), SA, and MD muscles (p < 0.05). Conclusions: Triceps facilitation did not increase scapular stability activity, but the activity levels in several other muscle groups (SA, MD, and triceps) were reduced during triceps facilitation compared with optimized posture or guided movement. Detailed analysis of this technique, including co-registered kinematic data and timing of muscle onset, is needed.

The Comparative Effects of Upper Thoracic Spine Thrust Manipulation Techniques in Individuals With Subacromial Pain Syndrome: A Randomized Clinical Trial

BACKGROUND

Subacromial pain syndrome (SPS) accounts for as much as 44% of shoulder pain encountered by physical therapists. Thoracic spine thrust manipulation (TSTM) is effective in the short term for improving pain and function in individuals with SPS, but its mechanisms remain elusive. Furthermore, it is unknown whether individuals with SPS respond differently based on the TSTM technique received.

OBJECTIVES

To compare the immediate effects of a supine TSTM, seated TSTM, and sham manipulation on the primary outcomes of self-reported pain, function, and satisfaction and secondary biomechanical impairments examined in individuals with SPS.

METHODS

Participants in this randomized clinical trial were randomized to receive a seated TSTM (n = 20), supine TSTM (n = 20), or sham manipulation (n = 20). The primary outcomes of self-reported pain, function, and satisfaction were measured via the Penn Shoulder Score. Secondary outcomes were changes in scapular upward rotation and posterior tilt; peak force generated in tests for the middle trapezius, lower trapezius, and serratus anterior; and pectoralis minor muscle length. Impairment measures were immediately reassessed, and the Penn Shoulder Score was reassessed after 48 hours.

RESULTS

There were no significant between-group differences in immediate or short-term follow-up outcomes.

CONCLUSION

Two TSTM techniques resulted in no differences in pain, satisfaction, and function when compared to a sham manipulation. Thoracic spine thrust manipulation did not have an immediate effect on the scapular impairments examined.

LEVEL OF EVIDENCE

Therapy, level 1. J Orthop Sports Phys Ther 2019;49(10):716-724. Epub 12 Mar 2019. doi:10.2519/jospt.2019.8484.

Electromyographic analysis of shoulder girdle muscle activation while performing a forehand topspin in elite table tennis athletes with and without shoulder impingement syndrome

BACKGROUND

Shoulder impingement syndrome is considered to be associated with an altered muscular activity, which is related to strategy changes in the movement plan. The present study aimed to investigate the differences in timing and intensity of activity of shoulder girdle muscles while performing a forehand topspin loop between elite table tennis players with and without shoulder impingement syndrome. The timing and activity amplitude of these shoulder girdle muscles have not been evaluated in other studies in table tennis elite athletes.

METHODS

Activation timing and activity levels of the upper trapezius, lower trapezius, and serratus anterior, anterior deltoid, supraspinatus, and biceps brachii muscles were measured in 30 table tennis players (Premier League tournament level or higher) with shoulder impingement syndrome and compared with 30 same-level healthy players while performing the forehand topspin loop.

RESULTS

The results indicated that the activity levels of the serratus anterior (P = .007) and supraspinatus (P = .001) muscles significantly decreased; however, the activity level of the upper trapezius significantly increased in the impingement compared with the healthy group (P = .009). The serratus anterior (P = .001) was activated significantly later, but the upper trapezius (P = .004) was activated significantly earlier in the impingement group.

CONCLUSION

Results of the present study support the theory that the activation and sequence of recruiting of the shoulder muscles are altered in people with impingement symptoms, suggesting that impingement syndrome may be associated with disturbed timing and activity level of shoulder girdle muscles.

Influence of adiposity and fatigue on the scapular muscle recruitment order

Background

Several authors have indicated that excess body weight can modify the electromyographic (EMG) amplitude due to the accumulation of subcutaneous fat. This accumulation of adipose tissue around the muscle would affect the metabolic capacity during functional activities. On the other hand, some authors have not observed differences in the myoelectric manifestations of fatigue between normal weight and obese people. Furthermore, these manifestations have not been investigated regarding EMG onset latency, which indicates a pattern of muscle activation between different muscles. The objective of this study was to determine whether an increase in body weight, skinfolds, and muscle fatigue modify the trapezius and serratus anterior (SA) onset latencies and to determine the scapular muscle recruitment order in fatigue and excess body weight conditions.

Methods

This cross-sectional study was carried out in a university laboratory. The participants were randomly assigned to the no-fatigue group (17 participants) or the fatigue (17 participants) group. The body mass index, skinfold thickness (axillary, pectoral, and subscapular), and percentage of body fat were measured. In addition, the onset latency of the scapular muscles [lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), and SA] was assessed by surface EMG during the performance of a voluntary arm raise task. A multiple linear regression model was adjusted and analyzed for the additive combination of the variables, percentage body fat, skinfold thickness, and fatigue. The differences in onset latency between the scapular muscles were analyzed using a three-way repeated measure analysis of variance. In all the tests, an alpha level <0.05 was considered statistically significant.

Results

For the MT, LT, and SA onset latencies, the body mass index was associated with a delayed onset latency when it was adjusted for the additive combination of percentage of body fat, skinfold thickness, and fatigue. Of these adjustment factors, the subscapular skinfold thickness (R ² = 0.51; β = 10.7; p = 0.001) and fatigue (R ² = 0.86; β = 95.4; p = 0.001) primarily contributed to the increase in SA onset latency. A significant muscle ×body mass index ×fatigue interaction (F = 4.182; p = 0.008) was observed. In the fatigue/excess body weight condition, the UT was activated significantly earlier than the other three scapular muscles (p < 0.001) and SA activation was significantly delayed compared to LT (p < 0.001).

Discussion

Excess body weight, adjusted for skinfold thickness (axillary and subscapular) and fatigue, increases the onset latency of the MT, LT, and SA muscles and modifies the recruitment order of scapular muscles. In fact, the scapular stabilizing muscles (MT, LT, and SA) increase their onset latency in comparison to the UT muscle. These results were not observed when excess body weight was considered as an individual variable or when adjusted by the percentage body fat.

Rationale and methods of a randomized clinical trial to compare specific exercise programs versus home exercises in patients with subacromial impingement syndrome

BACKGROUND

Subacromial impingement syndrome (SIS) is a common clinical condition with a multifactorial etiology. Currently, there is a great variety of therapeutic exercise modalities aimed at treating SIS. Based on alterations of the glenohumeral and/or dysfunctional scapular kinematics associated with SIS, we hypothesize that the implementation of a specific exercise program with special focus on the correction of muscle deficits should be more effective than nonspecific exercises performed at home. This article describes the rationale and methods of study aimed at testing the effectiveness of specific exercise programs versus home exercises in patients with SIS.

METHOD/DESIGN

Ninety-four patients between the ages of 18 and 50 years referred to the Physical Therapy department of the Clinical Hospital San Borja Arriaran in Chile will be randomized to 2 treatment arms. The intervention group will receive a program of specific exercises with a duration of 12 weeks, taking as a reference the algorithm of clinical decision proposed by a panel of experts. The control group will receive a program of nonspecific exercises to perform at home. Three evaluations will be performed: before the initiation of treatment, and at the 12-week and 1-year follow-up. The primary outcome measure will be the shoulder function by the Constant-Murley questionnaire, and the secondary outcome measures will be the upper extremity function by the Disabilities of the Arm, Shoulder and Hand questionnaire, and pain by the visual analog scale.

DISCUSSION

This article reports the design of a randomized clinical trial aimed at assessing the effectiveness of a specific exercise program versus home exercises in patients with SIS.

TRIAL REGISTRATION

Brazilian registry of clinical trials UTN number U1111-1204-0268. Registered 27 September 2017.

The three-dimensional shoulder pain alignment (3D-SPA) mobilization improves pain-free shoulder range, functional reach and sleep following stroke: a pilot randomized control trial

Background and purpose: Following a stroke, three-dimensional clavicular/scapular/humeral joint rotations may become restricted and contribute to post-stroke shoulder pain. This study examined whether a treatment group provided with current standard treatment plus the proposed "Three-dimensional Shoulder Pain Alignment" mobilization protocol demonstrated improved pain-free shoulder range, functional reach and sleep compared to a control group provided with standard treatment alone.Methods: In this double-blinded parallel-group randomized control trial, treatment and control subjects with moderate/severe post-stroke upper extremity impairment and shoulder pain were treated 3x/week for 4 weeks. Outcome measures included changes in pain-free three-dimensional clavicular/scapular/humeral range (using computerized digitization), pain during sleep and functional reach (using the Pain Intensity-Numerical Rating Scale), and pain location/prognostic indicators (using the Chedoke-McMaster Stroke Assessment-Shoulder Pain Inventory).Results: Compared to controls (n = 10) the treatment group (n = 10) demonstrated significantly improved three-dimensional clavicular/scapular/humeral pain-free range during shoulder flexion and abduction (p < 0.05; Hedges g > 0.80), large effect sizes for decreased pain during sleep and functional reach to the head and back (OR range: 5.44-21.00), and moderate effect size for improved pain/prognostic indicators (OR = 3.86).Conclusions: The Three-Dimensional Shoulder Pain Alignment mobilization protocol significantly improved pain-free range of motion, functional reach and pain during sleep in shoulders with moderate/severe post-stroke upper-extremity impairment.Implications for rehabilitationAlthough three-dimensional clavicular/scapular/humeral rotations are an essential component of normal pain-free shoulder range of motion, current guidelines for treatment of post-stroke shoulder pain only includes uni-dimensional mobilizations for joint alignment and pain management.The Three-Dimensional Shoulder Pain Alignment (3D-SPA) mobilization protocol incorporates multi-dimensional mobilizations in various planes of shoulder movement.The current study results demonstrate proof-of-concept regarding the 3D-SPA mobilization, and this approach should be considered as an alternative to the uni-dimensional mobilizations currently used in clinical treatment guidelines for post-stroke shoulder pain.

Evaluation of Shoulder Strength and Kinematics as Risk Factors for Shoulder Injury in United States Special Forces Personnel

Background

Musculoskeletal injuries at the shoulder are highly prevalent and place a large burden on United States Special Forces personnel. Literature is lacking regarding the risk factors for these types of injuries.

Purpose/Hypothesis

The purpose of this study was to evaluate the association of shoulder strength and kinematic characteristics, which have shown retrospective associations with shoulder conditions/injuries, with prospectively collected shoulder injuries. We hypothesized that lower strength and abnormal kinematics would be predictive of future shoulder injury.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 140 male Special Forces operators underwent a musculoskeletal evaluation of the shoulder that included a scapular kinematic assessment during a humeral elevation task and isokinetic strength testing of the scapular protractors/retractors, external/internal rotators, and elevators of the shoulder. From strength assessments, ipsilateral strength ratios and bilateral strength asymmetries were also calculated. Musculoskeletal injuries of the shoulder were collected prospectively by use of medical chart reviews at 365 days following the evaluation. Separate generalized estimating equations (GEEs) and simple logistic regressions were used to analyze the association between baseline predictors and development of shoulder injury.

Results

Results of the GEEs showed no significant prediction of shoulder injury by shoulder strength (odds ratio [OR], 1.00-1.03), ipsilateral strength ratios (OR, 0.43-2.12), or scapular kinematics (OR, 0.99-1.01). Logistic regression indicated that none of the bilateral asymmetries were significantly predictive of shoulder injury (OR, 1.00-1.04).

Conclusion

The results indicate that shoulder strength and kinematic characteristics are not risk factors for shoulder injury in the Special Forces population. These findings are in opposition to the general findings of previous research using a retrospective analysis.

Comparison of Shoulder Protraction Strength and Electromyography Activity of Serratus Anterior and Pectoralis Major in Subjects With or Without a Winged Scapula

CONTEXT

A winged scapula (WS) is associated with faulty posture caused by weakness of the serratus anterior (SA), which mainly acts as a scapular stabilizer muscle. It is important to accurately assess and train the SA muscle with a focus on scapula stabilizers during musculoskeletal rehabilitation of individuals with a WS.

OBJECTIVE

The authors examined muscle activity in the SA and pectoralis major (PM), upper trapezius (UT), and anterior deltoid (AD) as well as shoulder protraction strength during isometric shoulder protraction in individuals with and without a WS.

DESIGN

Cross-sectional study.

SETTING

A clinical biomechanics laboratory.

PARTICIPANTS

In total, 27 males with no shoulder, neck, or upper-extremity pain participated.

MAIN OUTCOME MEASURES

Isometric shoulder protraction strength was collected and surface electromyography used to measure the activity of the SA, PM, UT, and AD muscles and selective SA activity ratio to other shoulder muscles.

RESULTS

Electromyography activity of the SA muscle and shoulder protraction strength were significantly lower in individuals with a WS compared with the non-WS group (P < .05). In contrast, PM muscle activity and the PM-to-SA, UT-to-SA, and AD-to-SA ratios were significantly greater in individuals with a WS than in individuals without winging (P < .05).

CONCLUSIONS

Isometric shoulder protraction for measuring SA strength in individuals with a WS should focus on isolated muscle activity of the SA, and SA strengthening exercises are important for individuals with a WS.