Role of scapular stabilizers in etiology and treatment of impingement syndrome

Shoulder Internal Rotator Strength as Risk Factor for Shoulder Pain in Volleyball Players

The aim of this study was to identify the intrinsic factors that could increase risk of shoulder pain in adolescent volleyball players. Twenty-eight young male volleyball players (between 14 and 18 years old) participated in this study. Athletes were submitted to: isokinetic muscle strength assessment of shoulder rotator muscles, ball service speed assessment, anterior and posterior drawer test, apprehension test, groove sign and scapular dyskinesia test. Athletes were followed for 16 weeks to monitor the presence of shoulder pain. All athletes were submitted to the same training protocol. During the 16 weeks, 28.5% of the athletes (n=8) experienced shoulder pain in the dominant limb higher than 3 according to Numerical Rating Scale criteria; 71.5% of the athletes (n=20) did not experience pain, or pain equal or lower than 3. The main result of our study was that the odds of feeling pain higher than 3 was significantly higher among players who presented higher values for internal rotation peak torque (OR=1.113, CI 95%=1.006 to 1.232 and p=0.038). The odds of feeling pain increased by 11% for every N·m of the internal rotator muscles. Pre-season isokinetic rotator strength assessments can help identify adolescent volleyball players at increased risk of a shoulder injury.

Does the Activity in Scapular Muscles During Plyometric Exercises Change When the Kinetic Chain Is Challenged?-An EMG Study

Werin, MB, Maenhout, AG, Icket, J, Jacxsens, N, Kempkes, E, and Cools, AM. Does the activity in scapular muscles during plyometric exercises change when the kinetic chain is challenged?-An EMG study. J Strength Cond Res XX(X): 000-000, 2020-Plyometric exercises for the shoulder are used in rehabilitation and in workout regime when the sport demands high speed power training. The aim of this clinical laboratory electromyography (EMG) study was to determine whether scapular muscle performance differs during plyometric shoulder exercises when changing the demand on the kinetic chain. Thirty healthy overhead athletes, with a mean age of 22.7 years (±2.2), performed 6 exercises, with both a low and a high demand on the kinetic chain, in prone, side and standing in positions. The EMG activity of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) on the tested side and bilateral of gluteus maximus (GM) and abdominal oblique externus (OE) was registered with wireless surface EMG. Intermuscular muscle ratios UT/SA, UT/MT, and UT/LT were also calculated. The level of significance set for the study was alpha = 0.05. The muscle ratio UT/SA was significantly lower (p < 0.05) when high demand on the kinetic chain compared with low. SA muscle activity showed significantly (<0.001) higher values in the prone position with high demand on the kinetic chain compared with low. All 3 trapezius muscle parts had significantly higher values (p < 0.001) in the prone compared with side and standing positions. The GM and OE showed significantly higher (p ≤ 0.01) activity in positions more demanding for the kinetic chain. When composing a strengthening or a rehabilitation program for athletes, the knowledge of how scapular and trunk muscles interact can be used to amplify the strengthening effect.

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

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

Regarding the Necessity of Functional Assessment Including Motor Control Assessment of Post-Mastectomy Patients Qualified for Latissimus Dorsi Breast Reconstruction Procedure-Pilot Study

The purpose of the paper is a functional assessment of post-mastectomy patients who underwent latissimus dorsi breast reconstruction (LDBR), and of healthy women, through an analysis of selected muscle function parameters, including motor control assessment. Twenty participants were included in the study (ten LDBR-procedure individuals and ten healthy controls). The research consisted of a DASH (The Disabilities of the Arm, Shoulder and Hand) questionnaire assessment, shoulder area static assessment, shoulder mobility assessment, latissimus dorsi flexibility assessment and shoulder motor control assessment. LDBR-procedure individuals-when compared to healthy controls-exhibited a decrease in physical aspects of quality of life, shoulder area postural alterations, limitations in shoulder mobility and decrease in shoulder motor control. LDBR procedure may have an influence on limiting shoulder active mobility, as well as on decrease of shoulder motor and postural control. Standard functional assessment diversified on motor control assessment of post-mastectomy patients qualified for the LDBR procedure seems to be necessary.

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

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

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.

The Swimmer's Shoulder: Multi-directional Instability

PURPOSE OF REVIEW

Swimmer's shoulder is the term used to describe the problem of shoulder pain in swimmers. Originally described as supraspinatus tendon impingement under the coracoacromial arch, it is now understood that several different pathologies can cause shoulder pain in competitive swimmers, including subacromial impingement syndrome, overuse and subsequent muscle fatigue, scapular dyskinesis, and laxity and instability.

RECENT FINDINGS

Swimmers may develop increased shoulder laxity over time due to repetitive use. Such excessive laxity can decrease passive shoulder stability and lead to rotator cuff muscle overload, fatigue, and subsequent injury in order to properly control the translation of the humeral head. Generalized laxity can be present up to 62% of swimmers, while a moderate degree of multi-directional instability can be present in the majority. Laxity in swimmers can be due to a combination of underlying inherent anatomical factors as well as from repetitive overhead activity. The role of excessive laxity and muscle imbalance are crucial in the swimmer's shoulder and should be well understood since they are the primary target of the training and rehabilitation program.

Scapular-focused exercise treatment protocol for shoulder impingement symptoms: Three-dimensional scapular kinematics analysis

BACKGROUND

The present study aimed to describe the effects of a periscapular strengthening and neuromuscular training protocol in three-dimensional scapular kinematics and resting positioning in participants with shoulder impingement symptoms. Self-reported function was also evaluated.

METHOD

The study group comprised 50 subjects with shoulder impingement syndrome (control group, n=25; treatment group, n=25). The treatment group underwent 8weeks of neuromuscular training and periscapular strengthening. Scapular kinematics was measured using an electromagnetic tracking device, and the Brazilian version of the Shoulder Pain and Disability Index (SPADI-Br) questionnaire was carried out before and after the treatment.

FINDINGS

In the resting position, treated subjects had lower (p<0.01) internal rotation of the scapula compared to the control group, with a large effect size (2.4). On the coronal plane, the treated group had less scapular upward rotation (p<0.01) and less internal rotation (p<0.05), with a medium effect size. On the sagittal plane, the treated group had less internal rotation (p<0.01), less upward rotation (p<0.05), and less scapular anterior tilt (p<0.01), with a medium effect size. On the scapular plane, a reduction in upward rotation (p<0.01) after the intervention was observed, with a large effect size. Moreover, a reduction in the total SPADI-Br score was found, with a mean difference of 32.4 [24.4; 40.4] points (p<0.01) after the implementation of the protocol and a large effect size (2.0).

INTERPRETATION

The results provide biomechanical support for the clinical rationale for indicating therapeutic exercises focused on the periscapular muscles to improve scapular dynamics.

Does taping in addition to physiotherapy improve the outcomes in subacromial impingement syndrome? A systematic review

BACKGROUND

Taping is used with or without other interventions for many purposes, especially to manage pain and improve functional activity in patients with shoulder pain.

OBJECTIVES

The aim of this review was to determine whether any taping technique in addition to physiotherapy care is more effective than physiotherapy care alone in patients with shoulder impingement syndrome.

METHODS

A systematic search of Cochrane Database of Systematic Review, MEDLINE (EBSCO), Physiotherapy Evidence Database (PEDro), CINAHL (EBSCO), PUBMED, AMED, EMBASE (OVID), The Kinesio Kinesio® Taping Method, Kinesio® Tex Tape UK and International websites ( www.kinesiotaping.co.uk ; www.kinesiotaping.com ) was conducted to June 2015. The outcome measures were pain, disability, range of motion and muscle strength. As data were not suitable for meta-analysis, narrative synthesis were applied.

RESULTS

Three randomized controlled trials and one controlled trial (135 patients) were included. The results were conflicting and weak on the effectiveness of taping as an adjunct therapy for improvement of pain, disability, range of motion and muscle strength.

CONCLUSION

Clinical taping in addition to physiotherapy interventions (e.g. exercise, electrotherapy, and manual therapy) might be an optional modality for managing patients with shoulder impingement syndrome, especially for the initial stage of the treatment; however, we need further robust, placebo controlled and consistent studies to prove whether it is more effective than physiotherapy interventions without taping.

Effects of scapular taping in young adults with shoulder pain and scapular dyskinesis

OBJECTIVE

To assess the immediate effects of scapular taping on pain, isometric force, and the level of activation of several scapular girdle muscles in individuals with shoulder pain and scapular dyskinesis.

MATERIALS AND METHODS

Ten individuals with shoulder pain during arm elevation and scapular dyskinesis were included and evaluated by using a visual analogue scale (VAS), pressure algometry, dynamometry, and surface electromyography. All assessments were performed before and immediately after the application of scapular taping.

RESULTS

Scapular taping did not change the electromyographic activity of the upper trapezius muscle (p = 0.041, IC95%: -0.8256 to 10.8752). The positive effects of taping application were related to pain reduction (p = 0.025) and improvement in pressure algometry in the middle deltoid muscle (p = 0.020, IC95%:-1.8910 to -0.0490). Maximal isometric force did not change after the application of taping (flexo-abduction p = 0.4136, external rotation p = 0.4261). Significant correlations were noted between the VAS and pressure pain threshold (PPT) for the upper trapezius muscle (r = -0.6643, p = 0.0361) as well as for the PPT measures of the middle deltoid and infraspinatus muscles before (r = 0.9491, p = 0.0001) and after (r = 0.9006, p = 0.0004) the application of taping.

CONCLUSION

Scapular taping was not effective for inducing changes in the electromyographic activity of the upper trapezius, lower trapezius, and serratus anterior muscles, nor in altering the isometric force of shoulder flexo-abduction and external rotation. However, taping was effective at improving the pressure algometry values of the middle deltoid. Significant correlations between the pressure algometry of the middle deltoid and infraspinatus muscles, both before and after the application of scapular taping, were noted.

Acromiohumeral Distance During Neuromuscular Electrical Stimulation of the Lower Trapezius and Serratus Anterior Muscles in Healthy Participants

CONTEXT

Compromise to the acromiohumeral distance has been reported in participants with subacromial impingement syndrome compared with healthy participants. In clinical practice, patients with subacromial shoulder impingement are given strengthening programs targeting the lower trapezius (LT) and serratus anterior (SA) muscles to increase scapular posterior tilt and upward rotation. We are the first to use neuromuscular electrical stimulation to stimulate these muscle groups and evaluate how the muscle contraction affects the acromiohumeral distance.

OBJECTIVE

To investigate if electrical muscle stimulation of the LT and SA muscles, both separately and simultaneously, increases the acromiohumeral distance and to identify which muscle-group contraction or combination most influences the acromiohumeral distance.

DESIGN

Controlled laboratory study.

SETTING

Human performance laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty participants (10 men and 10 women, age = 26.9 ± 8.0 years, body mass index = 23.8) were screened.

INTERVENTION(S)

Neuromuscular electrical stimulation of the LT and SA.

MAIN OUTCOME MEASURE(S)

Ultrasound measurement of the acromiohumeral distance.

RESULTS

Acromiohumeral distance increased during contraction via neuromuscular electrical stimulation of the LT muscle (t(19) = -3.89, P = .004), SA muscle (t(19) = -7.67, P = .001), and combined LT and SA muscles (t(19) = -5.09, P = .001). We observed no differences in the increased acromiohumeral distance among the 3 procedures (F(2,57) = 3.109, P = .08).

CONCLUSIONS

Our results supported the hypothesis that the muscle force couple around the scapula is important in rehabilitation and scapular control and influences acromiohumeral distance.

Effect of Exercise Speed and Isokinetic Feedback on the Middle and Lower Serratus Anterior Muscles during Push-up Exercises

[Purpose] This study assessed the use of different exercise speeds and isokinetic feedback on the middle and lower serratus anterior muscles during push-up exercises. [Subjects] Ten male workers voluntarily consented to participate in the study. [Methods] The subjects performed push-up exercises under three conditions. Surface electrodes were placed on the dominant right side of the middle and lower serratus anterior muscles. [Results] The middle and lower SA muscle activities under condition 2 were significantly decreased when compared with those under conditions 1 and 3. The middle SA activity under condition 3 was significantly increased when compared with that under condition 1. [Conclusion] This study suggests that proper selection of push-up exercise speed may be necessary for selective strengthening of the SA and that isokinetic feedback information obtained using an accelerator can help in selective strengthening of the middle SA.

Rehabilitation for Subacromial Impingement Starts at the Scapula

Subacromial impingement, especially secondary subacromial impingement, is a common malady of athletes and non-athletes alike. Although several pathologies may lead to impingement, they all relate back to poor posture. Over time, postural changes increase stress to soft tissue structures to change both alignment and performance. Injury results as low-level stresses impact weakening tissues to the point of overload. Crucial to effective treatment of secondary subacromial impingement is the identification and correction of all causes. Basic to successful treatment is correction of posture, including scapular posture and muscles which control, stabilize, and move the scapula. An evidence-based approach to not only identifying the causes but also creating a treatment regimen to effectively resolve secondary subacromial impingement is presented.

Does scapula taping facilitate recovery for shoulder impingement symptoms? A pilot randomized controlled trial

Scapula taping is a commonly used adjunctive treatment for shoulder impingement pathology. However, this intervention has not previously been subject to formal investigation. A pilot single-blind randomized controlled trial was conducted to evaluate facilitatory taping as an adjunct to routine physiotherapy management. Twenty-two subjects with unilateral shoulder impingement symptoms were randomized into a taping with routine physiotherapy or a routine physiotherapy only group. The intervention group had scapula taping applied three times per week for the first two weeks of their treatment. All subjects were assessed at baseline, then at 2 and 6 weeks after the commencement of treatment. Pain and functional ability were assessed using the Shoulder Pain and Disability Index, range of shoulder elevation, and self-reported pain on elevation. At 2 weeks, the taping group demonstrated a strong trend toward reduced pain both on self-reported activity (SPADI pain subscale mean for taping 27.0 versus 41.5 for control) and pain during measured abduction (mean VAS 22.8 for taped, 46.8 for control), statistical power being limited by small sample size. No similar trend was evident in the SPADI disability subscale. The magnitude of the differences was reduced at 6-week follow-up. This study provides preliminary evidence for a short-term role for scapula taping as an adjunct to routine physiotherapy in the management of shoulder impingement symptoms but also highlights the need for consideration on a case basis relating to risk factors for skin reaction.

Scapular dyskinesis in trapezius myalgia and intraexaminer reproducibility of clinical tests

The aims were to test the intraexaminer reproducibility and report the presence of specific clinical variables of scapular dyskinesis in cases with trapezius myalgia and healthy controls, along with general health and work ability. A total of 38 cases and 23 controls were tested for scapular dyskinesis, general health, and work ability, and 19 cases and 14 controls participated in the reproducibility study. Intraexaminer reproducibility was good to excellent for 6 of 10 clinical variables (Intraclass Correlation Coefficient [ICC] 0.76-0.91; kappa 0.84-1.00), and fair to good for four variables (ICC 0.42-0.74), test for muscular weakness having the lowest ICC (0.42). Cases showed significantly larger medial border misalignment, larger lower horizontal distance of the inferior scapular angle and larger passive shoulder internal rotation, by 110% (1.02 cm), 15% (1.38 cm), and 8% (5.5°), respectively. Cases with the highest degree of scapular dyskinesis showed reduced work ability and general health. The present specific clinical variables on scapular dyskinesis showed satisfactory intraexaminer reproducibility. An increased standardization must be implemented to increase reproducibility of tests for muscular weakness, and the interexaminer reproducibility must be tested for all variables. Finally, scapular dyskinesis in cases with trapezius myalgia must be followed longitudinally for clinical importance.

Scapular positioning in overhead athletes with and without shoulder pain: a case-control study

Abnormalities of scapular positioning are considered important risk factors for developing shoulder disorders. This study analyses the scapular positioning pattern in a group of overhead athletes with and without shoulder pain. In a multi-center blinded case-control study, 36 shoulder pain athletes (19 men, 17 women), were compared with 36 unimpaired athletes free of shoulder pain, matched for gender, age, hand dominance and body mass index. The blinded assessor performed visual observation, the measurement of the distance between the acromion and the table, inclinometry and the kinetic medial rotation test for dynamic scapular control in random order. Athletes with shoulder pain demonstrate scapular asymmetry in the sagittal plane, observed visually as anterior tilting on the painful side. Athletes with shoulder pain show a lack of scapular motor control on their painful side in contrast to their pain-free side. No scapular positioning or motor control differences were found in athletes with or without shoulder pain.

Trapezius muscle timing during selected shoulder rehabilitation exercises

STUDY DESIGN

Controlled laboratory study.

OBJECTIVES

To examine the timing of the 3 portions of the trapezius muscle in relation to the posterior deltoid (PD) muscle and in relation to one another during 4 selected shoulder exercises: (1) prone extension, (2) forward flexion in side lying, (3) external rotation in side lying, and (4) prone horizontal abduction with external rotation.

BACKGROUND

Deficiencies in trapezius muscle recruitment have been identified in patients with shoulder pain. Alterations in the trapezius muscle activation level and timing have been identified in previous research. Scapular muscle exercises in which the middle trapezius (MT) and lower trapezius (LT) muscle showed optimal activity with minimal upper trapezius (UT) muscle participation have been recently identified. However, it is currently unknown if these exercises also promote early activation of the scapular stabilizing musculature.

METHODS

The intermuscular and intramuscular timing of muscle activation (based on an activation level of greater than 10% maximum voluntary contraction beyond basic activity) of the 3 portions of the trapezius muscle during 4 exercises were examined by surface EMG in 30 healthy subjects on the dominant side (14 males, 16 females). A 1-sample t test was used to determine which portions of the trapezius muscle were activated significantly earlier or later than the PD (intermuscular timing). An analysis of variance for repeated measures (3 levels) was used for each exercise to determine possible timing differences among the 3 portions of the trapezius muscle (intramuscular timing).

RESULTS

Intermuscular and intramuscular differences in timing of the portions of the trapezius muscle were found. The UT was activated significantly later than the PD (P<.01), and the MT was activated significantly earlier than the PD (P<.01), during the prone extension exercise. During the horizontal abduction with external rotation exercise, the MT (P<.01) and the LT (P = .01) were activated significantly earlier than the PD. During prone extension, side-lying external rotation, and prone horizontal abduction with external rotation, significant differences were found between the UT and MT, between the UT and LT, but not between the MT and LT. In these exercises the MT and LT were activated significantly earlier than the UT. During forward flexion in side lying, no significant timing differences were found between the activation of the portions of the trapezius.

CONCLUSIONS

With the exception of the LT during prone extension, the prone extension exercise and the prone horizontal abduction with external rotation exercise promote early activation of the MT and LT in relation to the scapular and glenohumeral prime mover. Taking into account the limited generalizability of the results due to a narrow age range, these exercises are potentially promising for the treatment of intermuscular and intramuscular timing disorders of the trapezius muscle.

Clinical assessment of scapular positioning in musicians: an intertester reliability study

CONTEXT

The reliability of the measurement of the distance between the posterior border of the acromion and the wall and the reliability of the modified lateral scapular slide test have not been studied. Overall, the reliability of the clinical tools used to assess scapular positioning has not been studied in musicians.

OBJECTIVE

To examine the intertester reliability of scapular observation and 2 clinical tests for the assessment of scapular positioning in musicians.

DESIGN

Intertester reliability study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty healthy student musicians at a single university.

MAIN OUTCOME MEASURE(S)

Two assessors performed a standardized observation protocol, the measurement of the distance between the posterior border of the acromion and the wall, and the modified lateral scapular slide test. Each assessor was blinded to the other's findings.

RESULTS

The intertester reliability coefficients (kappa) for the observation in relaxed position, during unloaded movement, and during loaded movement were 0.41, 0.63, and 0.36, respectively. The kappa values for the observation of tilting and winging at rest were 0.48 and 0.42, respectively; during unloaded movement, the kappa values were 0.52 and 0.78, respectively; and with a 1-kg load, the kappa values were 0.24 and 0.50, respectively. The intraclass correlation coefficient (ICC) of the measurement of the acromial distance was 0.72 in relaxed position and 0.75 with the participant actively retracting both shoulders. The ICCs for the modified lateral scapular slide test varied between 0.63 and 0.58.

CONCLUSIONS

Our results demonstrated that the modified lateral scapular slide test was not a reliable tool to assess scapular positioning in these participants. Our data indicated that scapular observation in the relaxed position and during unloaded abduction in the frontal plane was a reliable assessment tool. The reliability of the measurement of the distance between the posterior border of the acromion and the wall in healthy musicians was moderate.

A clinical method for identifying scapular dyskinesis, part 2: validity

CONTEXT

Although clinical methods for detecting scapular dyskinesis have been described, evidence supporting the validity of these methods is lacking.

OBJECTIVE

To determine the validity of the scapular dyskinesis test, a visually based method of identifying abnormal scapular motion. A secondary purpose was to explore the relationship between scapular dyskinesis and shoulder symptoms.

DESIGN

Validation study comparing 3-dimensional measures of scapular motion among participants clinically judged as having either normal motion or scapular dyskinesis.

SETTING

University athletic training facilities.

PATIENTS OR OTHER PARTICIPANTS

A sample of 142 collegiate athletes (National Collegiate Athletic Association Division I and Division III) participating in sports requiring overhead use of the arm was rated, and 66 of these underwent 3-dimensional testing.

INTERVENTION(S)

Volunteers were viewed by 2 raters while performing weighted shoulder flexion and abduction. The right and left sides were rated independently as normal, subtle dyskinesis, or obvious dyskinesis using the scapular dyskinesis test. Symptoms were assessed using the Penn Shoulder Score.

MAIN OUTCOME MEASURE(S)

Athletes judged as having either normal motion or obvious dyskinesis underwent 3-dimensional electromagnetic kinematic testing while performing the same movements. The kinematic data from both groups were compared via multifactor analysis of variance with post hoc testing using the least significant difference procedure. The relationship between symptoms and scapular dyskinesis was evaluated by odds ratios.

RESULTS

Differences were found between the normal and obvious dyskinesis groups. Participants with obvious dyskinesis showed less scapular upward rotation (P < .001), less clavicular elevation (P < .001), and greater clavicular protraction (P = .044). The presence of shoulder symptoms was not different between the normal and obvious dyskinesis volunteers (odds ratio = 0.79, 95% confidence interval = 0.33, 1.89).

CONCLUSIONS

Shoulders visually judged as having dyskinesis showed distinct alterations in 3-dimensional scapular motion. However, the presence of scapular dyskinesis was not related to shoulder symptoms in athletes engaged in overhead sports.

Applicability of the coactivation method in assessing synergies of the scapular stabilizing muscles

HYPOTHESIS

This study investigated the feasibility of quantifying the coactivation levels in the evaluation of synergisms of the scapular stabilizing muscles during the elevation and lowering of the arms. This method, which quantifies the overlapping area of the normalized electromyographic (EMG) activity, could be applicable in assessing such muscular synergies.

MATERIALS AND METHODS

Both shoulders of 10 healthy volunteers were assessed. The coactivation of 3 synergic muscular groups (upper, middle and lower trapezius; upper trapezius and serratus anterior; middle trapezius and serratus anterior) and the isolated electromyographic activity of each muscle were analyzed.

RESULTS

Analysis of variance revealed that the coactivation values between the synergic groups were different from the isolated levels of each respective muscle for both movements (24.42 < F < 40.12; df=6; p < 0.001). The coactivation values of all groups during elevation were different from those during the lowering of the arms (13.31 <F < 959.92; df=1; p <or= 0.002), with progressive increases in EMG activity during the elevation and decreases during the lowering of the arms.

CONCLUSION

The significant differences in EMG activity between the isolated and the coactivation methods indicated that the coactivation method was adequate to assess the scapular muscular synergies.

Upper and lower trapezius muscle activity in subjects with subacromial impingement symptoms: is there imbalance and can taping change it?

OBJECTIVES

To investigate (i) whether subacromial impingement symptoms (SIS) were associated with upper and lower trapezius muscle imbalance and (ii) the effect of a scapula taping technique on upper and lower trapezius muscle activity.

DESIGN

Cross-sectional study with nested within-subject intervention.

SETTING

University research laboratory.

PARTICIPANTS

Subjects who demonstrated SIS (n=16) on clinical testing and an age and gender matched group of asymptomatic subjects (n=32).

MAIN OUTCOME MEASURES

Surface electromyography (EMG) to measure activity in the upper (UFT) and lower (LFT) fibres of trapezius during repeated humeral elevation in the scapular plane.

RESULTS

Symptomatic subjects demonstrated a significantly (95% CI 2.13 to 4.17, p=0.019) higher ratio of UFT:LFT activity than the asymptomatic subjects (95% CI 1.35 to 2.25). With tape in situ the symptomatic subjects demonstrated a significant (95% CI -8.6% to -17.3%, p<0.001) reduction in UFT activity but no significant (95% CI +2.8% to -17.5%, p=0.145) change in activity of LFT. No relationship (r=- 0.116, p=0.669) was found between the degree of underlying muscle imbalance and the reduction in UFT under the taped condition for the symptomatic group.

CONCLUSION

Subacromial impingement symptoms are associated with altered upper and lower trapezius muscle activity which can be partially addressed by the application of tape.

A clinical method for identifying scapular dyskinesis, part 1: reliability

CONTEXT

Shoulder injuries are common in athletes involved in overhead sports, and scapular dyskinesis is believed to be one causative factor in these injuries. Many authors assert that abnormal scapular motion, so-called dyskinesis, is related to shoulder injury, but evidence from 3-dimensional measurement studies regarding this relationship is mixed. Reliable and valid clinical methods for detecting scapular dyskinesis are lacking.

OBJECTIVE

To determine the interrater reliability of a new test designed to detect abnormal scapular motion.

DESIGN

Correlation design using ratings from multiple pairs of testers.

SETTING

University athletic training facilities.

PATIENTS OR OTHER PARTICIPANTS

A sample of 142 athletes (from National Collegiate Athletic Association Divisions I and III) participating in sports requiring intense overhead arm use.

INTERVENTION(S)

Participants were videotaped from the posterior aspect while performing 5 repetitions of bilateral, weighted (1.4-kg [3-lb] or 2.3-kg [5-lb]) shoulder flexion and frontal-plane abduction. Videotapes from randomly chosen participants were subsequently viewed and independently rated for the presence of scapular dyskinesis by 6 raters (3 pairs), with each pair rating 30 different participants. Raters were trained to detect scapular dyskinesis using a self-instructional format with standardized operational definitions and videotaped examples of normal and abnormal motion.

MAIN OUTCOME MEASURE(S)

Scapular dyskinesis was defined as the presence of either winging or dysrhythmia. Right and left sides were rated independently as normal, subtle, or obvious dyskinesis. We calculated percentage of agreement and weighted kappa (kappa(w)) coefficients to determine reliability.

RESULTS

Percentage of agreement was between 75% and 82%, and kappa(w) ranged from 0.48 to 0.61.

CONCLUSIONS

The test for scapular dyskinesis showed satisfactory reliability for clinical use in a sample of overhead athletes known to be at increased risk for shoulder symptoms.

Scapular and rotator cuff muscle activity during arm elevation: A review of normal function and alterations with shoulder impingement

OBJECTIVE: The purpose of this manuscript is to review current knowledge of how muscle activation and force production contribute to shoulder kinematics in healthy subjects and persons with shoulder impingement. RESULTS: The middle and lower serratus anterior muscles produce scapular upward rotation, posterior tilting, and external rotation. Upper trapezius produces clavicular elevation and retraction. The middle trapezius is primarily a medial stabilizer of the scapula. The lower trapezius assists in medial stabilization and upward rotation of the scapula. The pectoralis minor is aligned to resist normal rotations of the scapula during arm elevation. The rotator cuff is critical to stabilization and prevention of excess superior translation of the humeral head, as well as production of glenohumeral external rotation during arm elevation. Alterations in activation amplitude or timing have been identified across various investigations of subjects with shoulder impingement as compared to healthy controls. These include decreased activation of the middle or lower serratus anterior and rotator cuff, delayed activation of middle and lower trapezius, and increased activation of the upper trapezius and middle deltoid in impingement subjects. In addition, subjects with a short resting length of the pectoralis minor exhibit altered scapular kinematic patterns similar to those found in persons with shoulder impingement. CONCLUSION: These normal muscle functional capabilities and alterations in patient populations should be considered when planning exercise approaches for the rehabilitation of these patients.

Radiographic analysis of commonly prescribed scapular exercises

HYPOTHESIS

The performance of scapular exercises in the context of a clinical model of fatigue will result in superior migration of the humeral head and alterations in shoulder kinematics on radiographic analysis.

MATERIALS AND METHODS

Six healthy male volunteers underwent a series of radiographs before and immediately following two scapular exercises. To reproduce a practice setting a clinical model of muscle fatigue was utilized. Radiographs were taken at various degrees of elevation. Glenohumeral angle (GA), scapulothoracic angle (SA), and the position of the humeral head on the glenoid (excursion) were measured on each radiograph. Two-tailed paired sample t-test were used to compare pre-fatigue to post fatigue measures.

RESULTS

Following fatigue there was a significant increase in excursion at 45, 90, and 135 degrees of elevation indicating superior migration of the humeral head. There was an increase in SA from 0 to 45 degrees and a decrease in GA from 45 to 90 degrees of elevation. From 90 to 135 degrees an increase in GA was observed.

DISCUSSION

The amount of superior migration of the humeral head observed following exercise was consistent with previously reported amounts of superior migration in patients with subacromial impingement. The alterations that occurred in shoulder kinematics following exercise may have resulted from parascapular muscle fatigue as well as rotator cuff muscle insufficiency.

CONCLUSION

In the context of a clinical model of fatigue, these scapular exercises resulted in superior migration of the humeral head and alterations in shoulder kinematics on radiographic analysis in healthy subjects.

LEVEL OF EVIDENCE

Basic science study.

Scapular positioning in athlete's shoulder : particularities, clinical measurements and implications

Despite the essential role played by the scapula in shoulder function, current concepts in shoulder training and treatment regularly neglect its contribution. The 'scapular dyskinesis' is an alteration of the normal scapular kinematics as part of scapulohumeral rhythm, which has been shown to be a nonspecific response to a host of proximal and distal shoulder injuries. The dyskinesis can react in many ways with shoulder motion and function to increase the dysfunction. Thoracic kyphosis, acromio-clavicular joint disorders, subacromial or internal impingement, instability or labral pathology can alter scapular kinematics. Indeed, alteration of scapular stabilizing muscle activation, inflexibility of the muscles and capsule-ligamentous complex around the shoulder may affect the resting position and motion of the scapula. Given the interest in the scapular positioning and patterns of motion, this article aims to give a detailed overview of the literature focusing on the role of the scapula within the shoulder complex through the sports context. Such an examination of the role of the scapula requires the description of the normal pattern of scapula motion during shoulder movement; this also implies the study of possible scapular adaptations with sports practice and scapular dyskinesis concomitant to fatigue, impingement and instability. Different methods of scapular positioning evaluation are gathered from the literature in order to offer to the therapist the possibility of detecting scapular asymmetries through clinical examinations. Furthermore, current concepts of rehabilitation dealing with relieving symptoms associated with inflexibility, weakness or activation imbalance of the muscles are described. Repeating clinical assessments throughout the rehabilitation process highlights improvements and allows the therapist to actualize rationally his or her intervention. The return to the field must be accompanied by a transitory phase, which is conducive to integrating new instructions during sports gestures. On the basis of the possible scapular disturbance entailed in sports practice, a preventive approach that could be incorporated into training management is encouraged.

Scapular muscular activity with shoulder impingement syndrome during lowering of the arms

OBJECTIVE

To compare isolated electromyographic (EMG) activity of the serratus anterior, upper, middle, and lower trapezius, as well as the coactivation of the upper and middle trapezius/serratus anterior in subjects with and without shoulder impingement syndrome (IS), during lowering of the arms.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Twenty young adults, 10 with unilateral IS degree I or II (mean age 28.6 +/- 5.89 years) and 10 without any complaints or history of previous shoulder lesions (mean age 29.0 +/- 5.35 years), matched by gender, age, and levels of physical activity.

MAIN OUTCOME MEASUREMENTS

Isolated EMG activity of the serratus anterior, upper, middle, and lower trapezius, as well as the coactivation of the upper trapezius and middle trapezius/serratus anterior. The EMG activity was quantified by root mean square calculations and normalized by maximal voluntary isometric contractions.

RESULTS

Significant differences between groups were found only for the coactivation of the middle trapezius/serratus anterior (F = 6.81; P = 0.02). No significant differences were found between sides (F = 0.05; P = 0.83) nor for interactions between sides and groups (F = 3.85; P = 0.07).

CONCLUSIONS

These findings pointed out the importance of evaluating the lowering of the arms in individuals with IS and suggested that measures of coactivation, besides reflecting the real purpose of the muscular actions during functional activities, are more sensitive to detect changes between groups. The evaluation of the coactivation of the middle trapezius/serratus anterior should be included in clinical assessment of individuals with IS and investigations on the etiology and progression of IS.

Effect of the Scapula Reposition Test on shoulder impingement symptoms and elevation strength in overhead athletes

STUDY DESIGN

Two group, repeated measures design.

OBJECTIVES

To determine whether manually repositioning the scapula using the Scapula Reposition Test (SRT) reduces pain and increases shoulder elevation strength in athletes with and without positive signs of shoulder impingement.

BACKGROUND

Symptom alteration tests may be useful in determining a subset of those with shoulder pathology who may benefit from interventions aimed at improving scapular motion abnormalities.

METHODS AND MEASURES

One hundred forty-two college athletes underwent testing for clinical signs of shoulder impingement. Tests provoking symptoms were repeated with the scapula manually repositioned into greater retraction and posterior tilt. A numeric rating scale was used to measure symptom intensity under both conditions. Isometric shoulder elevation strength was measured using a mounted dynamometer with the scapula in its natural position and with manual repositioning. A paired t test was used to compare the strength between positions. The frequency of a significant increase in strength with scapular repositioning, defined as the minimal detectable change (90% confidence interval), was also assessed.

RESULTS

Of the 98 athletes with a positive impingement test, 46 had reduced pain with scapular repositioning. Although repositioning produced an increase in strength in both the impingement (P=.001) and non-impingement groups (P=.012), a significant increase in strength was found with repositioning in only 26% of athletes with, and 29% of athletes without positive signs for shoulder impingement.

CONCLUSION

The SRT is a simple clinical test that may potentially be useful in an impairment based classification approach to shoulder problems.

Rehabilitation of scapular muscle balance: which exercises to prescribe?

BACKGROUND

Strengthening exercises for the scapular muscles are used in the treatment of scapulothoracic dysfunction related to shoulder injury. In view of the intermuscular and intramuscular imbalances often established in these patients, exercises promoting lower trapezius (LT), middle trapezius (MT), and serratus anterior (SA) activation with minimal activity in the upper trapezius (UT) are recommended.

HYPOTHESIS

Of 12 commonly used trapezius strengthening exercises, a selection can be performed for muscle balance rehabilitation, based on a low UT/LT, UT/MT, or UT/SA muscle ratio.

STUDY DESIGN

Controlled laboratory study.

METHODS

Electromyographic activity of the 3 trapezius parts and the SA was measured in 45 healthy subjects performing 12 commonly described scapular exercises, using surface electromyography.

RESULTS

For each intramuscular trapezius ratio (UT/LT, UT/MT), 3 exercises were selected for restoration of muscle balance. The exercises side-lying external rotation, side-lying forward flexion, prone horizontal abduction with external rotation, and prone extension were found to be the most appropriate for intramuscular trapezius muscle balance rehabilitation. For the UT/SA ratio, none of the exercises met the criteria for optimal intermuscular balance restoration.

CONCLUSION

In cases of trapezius muscle imbalance, some exercises are preferable over others because of their low UT/LT and UT/MT ratios.

CLINICAL RELEVANCE

In the selection of rehabilitation exercises, the clinician should have a preference for exercises with high activation of the LT and MT and low activity of the UT.

Subacromial Impingement Syndrome as a Consequence of Botulinum Therapy to the Upper Trapezii: A Case Report

Scapular upward rotation is predominantly achieved via a force coupling involving the upper and lower trapezius and the serratus anterior. Although studies have shown a relationship between abnormal scapular motion and subacromial impingement, it has been unclear whether the altered scapular biomechanics represent a cause, or consequence, of impingement. We present a 49-year-old woman with refractory myofascial pain of many years duration who developed subacromial impingement syndrome (SIS) following a series of botulinum toxin injections to the bilateral upper trapezii. Although botulinum therapy effectively reduced the patient's refractory myofascial pain, signs and symptoms of SIS developed in association with the upper trapezii weakness after the third set of injections. Botulinum therapy was discontinued and nonsteroidal anti-inflammatory medication markedly reduced the new symptoms, which completely resolved within 3 months. This case, which afforded a unique opportunity to follow the consequences of weakening scapular stabilizers over time, provides evidence for the etiologic role of scapular dyskinesis in SIS and shows that SIS is a potential complication of botulinum therapy for myofascial pain involving the scapular stabilizers.

Scapular Positioning in Patients With Shoulder Pain: A Study Examining the Reliability and Clinical Importance of 3 Clinical Tests

OBJECTIVE

To examine the interobserver reliability, internal consistency, and clinical importance of 3 clinical tests for the assessment of scapular positioning in patients with shoulder pain.

DESIGN

Prospective repeated-measures design.

SETTING

Private practices for physical therapy and hospital outpatient physical therapy divisions.

PARTICIPANTS

Twenty-nine patients with shoulder pain who were diagnosed by a physician as having a shoulder disorder.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Study participants filled in a visual analog scale for pain and the Shoulder Disability Questionnaire. Next, 2 assessors performed the following tests: measurement of the distance between the posterior border of the acromion and the table, measurement of the distance from the medial scapular border to the fourth thoracic spinous processes, and the lateral scapular slide test.

RESULTS

The interobserver reliability coefficients were greater than .88 (intraclass correlation coefficients) for the measurement of the distance between the posterior border of the acromion and the table, were greater than .50 for the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes, and were greater than .70 for the lateral scapular slide test. The Cronbach alpha coefficient for internal consistency for all tests was .88. No associations between the outcome of the tests and self-reported pain severity or disability were found.

CONCLUSIONS

These data provide evidence favoring the interobserver reliability of 2 of 3 tests for the assessment of scapular positioning in patients with shoulder pain. The clinical importance of the tests' outcomes, however, is questionable.

Shoulder impingement: the effect of sitting posture on shoulder pain and range of motion

The re-education of spinal posture is an integral part of shoulder impingement management yet supporting evidence is limited. The purpose of this study was to evaluate the effect of slouched versus erect sitting posture on shoulder pain intensity and range of motion (ROM) in subjects with impingement. A same-subject repeated-measures design was utilized. Maximum active shoulder flexion and associated pain intensity were measured in 28 subjects in slouched and erect sitting postures, using video-analysis and visual analogue scales, respectively. An intra-tester reliability study of the video-analysis system was completed and intra-class correlation coefficients calculated. Shoulder flexion differences between slouched and erect sitting posture were analysed using a repeated-measures analysis of variance (ANOVA). The intra-tester reliability of the video-analysis method was found to be 'excellent' (ICC = 0.99). Flexion ROM was significantly greater in the erect sitting posture (F = 100.3, P < 0.0001); the mean ROM difference between postures was 17.67 degrees (+/- 9.17 degrees). There was no significant difference in pain intensity between postures (F = 1.9, P = 0.179). An erect sitting posture appeared to increase active shoulder flexion in subjects with shoulder impingement, although there were no differences in reported pain intensity. Further research is required to investigate the long-term effects of postural re-education.

Subacromial impingement syndrome: the effect of changing posture on shoulder range of movement

STUDY DESIGN

Random allocation of subjects into a placebo-controlled, crossover study.

OBJECTIVES

To investigate the effect of changing thoracic and scapular posture on shoulder flexion and scapular plane abduction range of motion in asymptomatic subjects, and in subjects with subacromial impingement syndrome.

BACKGROUND

Changes in upper body posture and concomitant imbalance of the muscle system have been proposed as one of the etiological mechanisms leading to subacromial impingement syndrome. Although clinicians commonly assess posture and devise rehabilitation programs to correct posture, there is little evidence to support this practice.

METHODS AND MATERIALS

Selected postural, range of movement, and pain measurements were investigated in 60 asymptomatic subjects and 60 subjects with subacromial impingement syndrome, prior to and following thoracic and scapular taping intended to change their posture.

RESULTS

Changing posture had an effect on all components of posture measured (P<.001) and these changes were associated with a significant increase (P<.001) in the range of motion in shoulder flexion and abduction in the plane of the scapula. Changing posture was not found to have a significant effect on the intensity of pain experienced by the symptomatic subjects, although the point in the range of shoulder elevation at which they experienced their pain was significantly higher (P<.001).

CONCLUSIONS

The findings of this investigation suggest that changing 1 or more of the components of posture may have a positive effect on shoulder range of movement and the point at which pain is experienced.

Rotator Cuff Impingement

OBJECTIVE

To present a case of shoulder impingement syndrome managed with a conservative multimodal treatment approach.

CLINICAL FEATURES

A patient had anterior shoulder pain and a diffuse ache in the right upper arm, with tenderness in the shoulder region on palpation. Shoulder range of motion was limited with pain and catching, coupled with limited and painful cervical motion. After physical and orthopedic examination, a clinical diagnosis of shoulder impingement syndrome was made.

INTERVENTIONS AND OUTCOME

The patient underwent a multimodal treatment protocol including soft tissue therapy, phonophoresis, diversified manipulation; and rotator cuff and shoulder girdle muscle exercises. Outcomes included pain measurement; range of motion of the shoulder, and return to normal daily, work, and sporting activities. At the end of the treatment protocol the patient was symptom free with all outcome measures normal. The patient was followed up at 4 and 12 weeks and continued to be symptom free with full range of motion and complete return to normal daily and pre-treatment activities.

CONCLUSION

This case report shows the potential benefit of a multimodal chiropractic protocol in resolving symptoms associated with shoulder impingement syndrome.

Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms

OBJECTIVES

To determine if the muscle force and electromyographic activity in the scapular rotators of overhead athletes with impingement symptoms showed differences between the injured and non-injured sides.

METHODS

Isokinetic peak force was evaluated during protraction and retraction of the shoulder girdle, with simultaneous recording of electromyographic activity of the three trapezius muscles and the serratus anterior muscle, in 19 overhead athletes with impingement symptoms.

RESULTS

Paired t tests showed significantly lower peak force during isokinetic protraction at high velocity (p<0.05), a significantly lower protraction/retraction ratio (p<0.01), and significantly lower electromyographic activity in the lower trapezius muscle during isokinetic retraction on the injured side than on the non-injured side (p<0.05).

CONCLUSION

These results confirm that patients with impingement symptoms show abnormal muscle performance at the scapulothoracic joint.

Therapeutic exercise and orthopedic manual therapy for impingement syndrome: a systematic review

OBJECTIVE

To review randomized controlled trials evaluating the effectiveness of therapeutic exercise and orthopedic manual therapy for the treatment of impingement syndrome.

DATA SOURCE

Reports up to October 2002 were located from MEDLINE, the Cochrane Database of Systematic Reviews, the Physiotherapy Evidence Database (PEDro), the TRIP database, and the Cumulative Index to Nursing & Allied Health Literature (CINAHL) using "shoulder" and "clinical trial"/"randomized controlled trial" as search terms.

STUDY SELECTION

Studies were included if (1) they were a randomized controlled trial; (2) they were related to impingement syndrome, rotator cuff tendinitis, or bursitis; (3) one of the treatments included therapeutic exercise or manual therapy.

DATA EXTRACTION

Two independent observers reviewed the methodological quality of the studies using an assessment tool developed by the Cochrane Musculoskeletal Injuries Group. Differences were resolved by consensus.

DATA SYNTHESIS

Seven trials met our inclusion criteria. After consensus, the mean methodological score for all studies was 13.9 +/- 2.4 (of 24). Four studies of 7, including the 3 trials with the best methodological score (67%), suggested some benefit of therapeutic exercise or manual therapy compared with other treatments such as acromioplasty, placebo, or no intervention.

CONCLUSIONS

There is limited evidence to support the efficacy of therapeutic exercise and manual therapy to treat impingement syndrome. More methodologically sound studies are needed to further evaluate these interventions.

Does taping influence electromyographic muscle activity in the scapular rotators in healthy shoulders?

Although taping techniques are commonly used in addition to exercise programmes in the rehabilitation of shoulder instability and secondary subacromial or internal impingement, few studies exist on the effect of taping on the muscle activity of the scapular rotators. The purpose of our study was to examine the influence of one particular tape on muscular activity in scapular muscles. Twenty healthy shoulders were examined with surface EMG recordings on the three parts of trapezius and serratus anterior muscle during dynamic full range of motion abduction and forward flexion. The movement direction, and tape and no-tape conditions were randomized. The statistical analyses with ANOVA repeated Measures (GLM model) showed significant differences among the means between the four muscles (P<0.05), two movement directions (P<0.05), applied resistance (P<0.01), and movement period (P<0.01). However, no significant difference was observed based on the application of tape. The results of our investigation revealed no significant influence of tape application on EMG activity in the scapular muscles in healthy subjects. Future research will be necessary to examine other parameters of neuromuscular control in order to determine possible proprioceptive changes in muscle recruitment with tape application.

Scapular muscle recruitment pattern: electromyographic response of the trapezius muscle to sudden shoulder movement before and after a fatiguing exercise

STUDY DESIGN

Test-retest reliability study and single-group repeated measures design.

OBJECTIVES

To evaluate the muscle latency times of the 3 portions of the trapezius muscle to a sudden arm movement in normal shoulders and to determine if this recruitment pattern is altered as a result of fatigue.

BACKGROUND

It has been suggested that shoulder impingement may be related to altered muscle activity and muscle fatigue in the scapular stabilizers. Fatigue-induced changes in latency times of the trapezius might influence scapular stability.

METHODS AND MEASURES

Muscle latency times were investigated in 30 healthy shoulders with surface electromyography. Muscle activity was measured in all 3 sections of the trapezius and the middle deltoid muscle during a sudden downward falling movement of the arm. Subsequently the shoulder was fatigued on an isokinetic dynamometer, after which muscle latency time measurement was repeated.

RESULTS

ANOVA for repeated measures revealed significant differences in latency times (P < 0.05) among the 4 muscles of interest. Although there were no significant differences among the 3 sections of the trapezius muscle, they all were recruited after the initialization of the deltoid muscle. The recruitment order of the shoulder muscles did not change with muscle fatigue. However, after fatigue, muscle responses were significantly slower in all muscles except for the lower trapezius (P < 0.05).

CONCLUSIONS

There is a specific recruitment sequence in the shoulder muscles in response to a sudden arm movement characterized by initial activation of the middle deltoid muscle and followed by simultaneous contraction of all 3 sections of the trapezius. This muscle activation pattern is delayed but not altered with fatigue.

The Effect of Scapular Taping on Shoulder Joint Repositioning

Context:

There is a lack of research on the effects of scapular tape on shoulder joint repositioning.

Objective:

To quantify the effects of scapular taping on shoulder joint repositioning during flexion and abduction.

Design:

Repeated measures before and after trial.

Setting:

Academic institution.

Participants:

36 subjects without shoulder pathology.

Intervention:

Scapular taping with flexion and abduction.

Main Outcome Measures:

Lateral scapular slide test, plumb-line assessment, and a depth measurement. Absolute error in joint repositioning in flexion and abduction at 3 angles with and without scapular taping was measured.

Results:

No differences were found for tape vs no tape in flexion (P= .92) or abduction (P= .40) or between winging and nonwinging subjects in flexion (P= .62) or abduction (P= .91).

Conclusions:

Scapular taping has no effect on joint repositioning during active shoulder flexion or abduction. Scapular winging does not affect active joint repositioning after scapular taping.

Quantification of posterior capsule tightness and motion loss in patients with shoulder impingement

The relationship between posterior capsule tightness and dysfunction has long been recognized clinically but has not been biometrically quantified. The purpose of this study was to quantify changes in range of motion and posterior capsule tightness in patients with dominant or nondominant shoulder impingement. Measurements of posterior capsule tightness and external and internal rotation range of motion were made in 31 patients with shoulder impingement and in 33 controls without shoulder abnormality. Patients with impingement in the nondominant arm had increased posterior capsule tightness and decreased internal and external rotation range of motion compared with controls. Patients with impingement in their dominant arm had increased posterior capsule tightness and reduced internal rotation range of motion but no significant loss of external rotation range of motion compared with controls. Posterior capsule tightness in impingement patients showed a significant correlation with loss of internal rotation range of motion. Patients with shoulder impingement in their nondominant arm had a more global loss of range of motion compared with patients having impingement in their dominant arm. We believe we have described a valid clinical measurement for identifying posterior capsule tightness in patients with shoulder impingement.