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Abstract Objectives Experimental pain is a commonly used method to draw conclusions about the motor response to clinical musculoskeletal pain. A systematic review was performed to determine if current models of acute experimental pain validly replicate the clinical experience of appendicular musculoskeletal pain with respect to the distribution and quality of pain and the pain response to provocation testing. Methods A structured search of Medline, Scopus and Embase databases was conducted from database inception to August 2020 using the following key terms: “experimental muscle pain” OR “experimental pain” OR “pain induced” OR “induced pain” OR “muscle hyperalgesia“ OR (“Pain model” AND “muscle”). Studies in English were included if investigators induced experimental musculoskeletal pain into a limb (including the sacroiliac joint) in humans, and if they measured and reported the distribution of pain, quality of pain or response to a provocation manoeuvre performed passively or actively. Studies were excluded if they involved prolonged or delayed experimental pain, if temporomandibular, orofacial, lumbar, thoracic or cervical spine pain were investigated, if a full text of the study was not available or if they were systematic reviews. Two investigators independently screened each title and abstract and each full text paper to determine inclusion in the review. Disagreements were resolved by consensus with a third investigator. Results Data from 57 experimental pain studies were included in this review. Forty-six of these studies reported pain distribution, 41 reported pain quality and six detailed the pain response to provocation testing. Hypertonic saline injection was the most common mechanism used to induce pain with 43 studies employing this method. The next most common methods were capsaicin injection (5 studies) and electrical stimulation, injection of acidic solution and ischaemia with three studies each. The distribution of experimental pain was similar to the area of pain reported in clinical appendicular musculoskeletal conditions. The quality of appendicular musculoskeletal pain was not replicated with the affective component of the McGill Pain Questionnaire consistently lower than that typically reported by musculoskeletal pain patients. The response to provocation testing was rarely investigated following experimental pain induction. Based on the limited available data, the increase in pain experienced in clinical populations during provocative maneuvers was not consistently replicated. Conclusions Current acute experimental pain models replicate the distribution but not the quality of chronic clinical appendicular musculoskeletal pain. Limited evidence also indicates that experimentally induced acute pain does not consistently increase with tests known to provoke pain in patients with appendicular musculoskeletal pain. The results of this review question the validity of conclusions drawn from acute experimental pain studies regarding changes in muscle behaviour in response to pain in the clinical setting.

Purpose: To summarise measurement properties of translated versions of the Shoulder Pain and Disability Index (SPADI) and to assess their methodological quality. Methods: Relevant studies testing measurement properties of translated versions of the SPADI in non-specific shoulder pain participants were included from 11 databases (August 2020). Two reviewers independently screened articles and assessed individual measurement property risk of bias using the COSMIN checklist as very good, adequate, doubtful or inadequate. For each measurement property results were pooled and rated sufficient, insufficient, or inconsistent. Synthesised evidence was graded as high, moderate, low or very low (GRADE approach). Results: Thirty-four studies (21 languages and 26 different versions) were included from 4402 articles. A total of 141 measurement properties were reported with 60 rated as very good or adequate. These included; internal consistency (19), test-retest reliability (4), construct validity (6), structural validity (10), measurement error (5), responsiveness (9), and cross-cultural validity (2). Comprehensibility was adequate in the Chinese, German, Nepali, Spanish and Urdu versions. Only the Danish, Dutch and Nepali versions confirmed all, or all but one, of their measurement properties with sound methodology. Pooled results of all measurement properties except structural validity were rated as sufficient. Quality of evidence was graded moderate to high with downgrading due to inconsistent results. Conclusion: Overall evidence suggests the SPADI is valid, reliable and responsive in translated form but less than half the measurement properties tested were of adequate quality. Further testing is required in many languages particularly in; test-retest reliability, measurement error and construct validity.

The aim of this systematic review was to summarise the effects of ergonomics interventions on work-related upper limb musculoskeletal pain and dysfunction, and on productivity in sonographers, surgeons and dentists. A total of 31 studies were included. All studies reported effects on upper limb pain. Nine studies reported effects on dysfunction and only two studies reported effects on productivity. Moderately strong evidence in reducing upper limb pain was found for instigation of microbreaks into long duration surgical procedures, and the use of wider, lighter handles in dental instruments. Moderate evidence was also found for use of prismatic glasses and favourable positioning in reducing upper limb pain. Weak, inconsistent or no evidence was found for all other ergonomics interventions in reducing upper limb pain and dysfunction and increasing productivity. The lack of high quality research, particularly in sonographers and in the outcome of productivity, should be addressed. Practitioner summary: This systematic review investigates the effectiveness of ergonomics interventions on upper limb pain, dysfunction and productivity in sonographers, dentists and surgeons. Instigation of microbreaks during long duration procedures and the use of wider, lighter instrument handles were most effective in reducing upper limb work-related pain. Abbreviations: ANOVA: analysis of variance; CLS: conventional laparoscopic surgery; DMAIC: define, measure, analyze, improve and control; GRADE: grading of recommendations, assessment, development and evaluations; HD: high definition; PRISMA: preferred reporting items for systematic reviews and meta-analyses; PROSPERO: The International Prospective Register of Systematic Reviews; RCT: randomised control trial; SILS: single incision laparoscopic surgery; VITOM: video telescopic operative microscope; WNSWLHD: Western New South Wales Local Health District; WMSD: work related musculoskeletal disorder.

Introduction It is commonly believed that the shoulder external rotation (ER) to internal rotation (IR) strength ratio is decreased in swimmers due to predominant IR loading during the pull-through (propulsive) phase which predisposes to shoulder pain. However, the evidence supporting this hypothesis is inconclusive. Therefore, the aim of this study was to examine shoulder rotation strength parameters in elite swimmers and investigate potential associations with shoulder pain. Methods Sixty-eight (40 men; age, 19.9 ± 3.2 yr) elite swimmers provided demographic and shoulder pain history data before measurement of shoulder rotation strength. Mixed model analyses were used to examine differences in shoulder IR and ER strength normalized to body weight (BW) and the shoulder rotation strength ratio. A multinomial logistic regression model was utilized to examine associations between shoulder rotation strength parameters and shoulder pain. Results Mean shoulder IR strength (BW) was approximately 0.29 for male swimmers and 0.26 for female swimmers. Mean shoulder ER strength (BW) was approximately 0.19 for male swimmers and 0.18 for female swimmer. The shoulder ER/IR strength ratio was approximately 0.70 bilaterally for all swimmers. There were no significant differences between dominant and nondominant shoulders in IR or ER strength normalized to BW (P ≥ 0.547). There were no associations between any shoulder strength parameters and shoulder pain (r = 0.032, P = 0.107). Conclusions Despite the high IR loading, optimal swimming technique does not alter the normal ER/IR strength ratio at the shoulder. Elite swimmers who report current or a history of shoulder pain demonstrate normal shoulder rotation strength ratios. The finding of symmetrical shoulder rotation strength points to side-to-side strength comparisons as a valuable clinical tool in managing swimmers with unilateral shoulder pain.

Background Patient-reported outcome measures (PROMs) are important tools in both clinical practice and research. However, no upper extremity PROM to assess physical disability is available in Nepali. The most commonly used and recommended questionnaire for the shoulder is the Disability of Arm, Shoulder and Hand (DASH). Therefore, the aim of the study was to translate and cross-culturally adapt the DASH into Nepali and determine its measurement properties. Methods The translation and cultural adaptation process followed international standard procedures. The translated Nepali version of the questionnaire (DASH-NP) was completed by 156 patients with shoulder pain from three Nepali hospitals at an initial assessment and by 121 at follow-up. A Nepali version of Global Rating of Change (GROC-NP) was completed at follow-up to dichotomise improved and stable participants. Measurement properties testing included: internal consistency (Cronbach's alpha), test-retest reliability (Intraclass Correlation Coefficient, ICC), Minimal Detectable Change (MDC), construct validity - factor analysis, hypothesis testing with the Shoulder Pain and Disability Index (SPADI) (Pearson Correlation = r) and responsiveness - Area Under the Curve with minimal important change. Results Significant adaptations such as changing measurement units, activities and terminology were incorporated to improve cultural relevance. Internal consistency (α = 0.92) and test-retest reliability (ICC = 0.97, 95% CI: 0.94–0.98, p

Introduction Sonographers in the Western New South Wales Local Health District (WNSWLHD) reported a musculoskeletal pain prevalence rate of 95%. Participatory ergonomics, where workers are consulted about improving work conditions, was utilised to identify work-related musculoskeletal disorder (WMSD) risks and potential solutions. The aim of this study was to compare the prevalence of WMSD in a cohort of sonographers before and after implementation of ergonomic changes that were driven by recommendations from a participatory ergonomics approach. Methods This observational mixed methods study analysed the impact of participatory ergonomic-driven interventions on changes on musculoskeletal pain in a cohort of sonographers employed within the WNSWLHD. A retrospective analysis of 10 sonographer WMSD pain surveys over five sites was completed, along with semi-structured interviews regarding which interventions were perceived as useful, which interventions were not implemented and any barriers to implementation. Results Installation of patient monitors, use of ergonomic scanning techniques and job rotation were perceived as responsible for decreased musculoskeletal pain. Taking lunch breaks and microbreaks, use of antifatigue mats and having two sonographers perform mobile exams were not fully implemented. No interventions were perceived as responsible for increased pain. Conclusion This small study provides preliminary evidence that a participatory ergonomics approach facilitated identification of occupation and site-specific risks for WMSD in the WNSWLHD, allowing implementation of ergonomic changes to be tailored to the workplace, resulting in a safer work environment for sonographers.

ObjectiveTo investigate the influence of trunk and lower limb motion on electromyography (EMG) muscle activity and recruitment patterns around the shoulder.DesignSystematic review.Data sourcesMEDLINE, CINAHL, PEDro, AMED, PubMed, Cochrane Central Register of Controlled trials, Cochrane Database of Systematic reviews, SportsDiscuss and PROSPERO.Eligibility criteriaStudies investigating both multiregional kinetic chain (KC) shoulder exercisesandlocalised non-kinetic chain (nKC) shoulder exercises in healthy subjects under the same experimental conditions were included in this review.ResultsKC exercises produced greater EMG activation levels in 5 of 11 studies for the lower trapezius. Of the remaining studies, five found no difference between the exercise types and one favoured nKC exercises. KC exercises produced greater EMG activation levels in 5 of 11 studies for the serratus anterior. Of the remaining studies, three reported the opposite and three found no significant difference between the exercise types. nKC exercises produced greater EMG activation in infraspinatus in three of four studies. KC exercises produced the lowest trapezius muscle ratios in all studies. Studies investigating the upper trapezius, middle trapezius, supraspinatus, subscapularis, biceps brachii, latifissimus dorsi, pectoralis major, deltoid, and trapezius and serratus anterior ratios showed inconsistency.ConclusionThis review found evidence that integrating the KC during shoulder rehabilitation may increase axioscapular muscle recruitment, produce lower trapezius muscle ratios and reduce the demands on the rotator cuff. Stepping appears preferable to squatting.PROSPERO registration numberCRD42015032557, 2015.

Calibration of neuromusculoskeletal models using functional tasks is performed to calculate subject-specific musculotendon parameters, as well as coefficients describing the shape of muscle excitation and activation functions. The objective of the present study was to employ a neuromusculoskeletal model of the shoulder driven entirely from muscle electromyography (EMG) to quantify the influence of different model calibration strategies on muscle and joint force predictions. Three healthy adults performed dynamic shoulder abduction and flexion, followed by calibration tasks that included reaching, head touching as well as active and passive abduction, flexion and axial rotation, and submaximal isometric abduction, flexion and axial rotation contractions. EMG data were simultaneously measured from 16 shoulder muscles using surface and intramuscular electrodes, and joint motion evaluated using video motion analysis. Muscle and joint forces were calculated using subject-specific EMG-driven neuromusculoskeletal models that were uncalibrated and calibrated using (i) all calibration tasks (ii) sagittal plane calibration tasks, and (iii) scapular plane calibration tasks. Joint forces were compared to published instrumented implant data. Calibrating models across all tasks resulted in glenohumeral joint force magnitudes that were more similar to instrumented implant data than those derived from any other model calibration strategy. Muscles that generated greater torque were more sensitive to calibration than those that contributed less. This study demonstrates that extensive model calibration over a broad range of contrasting tasks produces the most accurate and physiologically relevant musculotendon and EMG-to-activation parameters. This study will assist in development and deployment of subject-specific neuromusculoskeletal models.

Purpose To examine the measurement properties of the Nepali version of the Quick-Disabilities of the Arm, Shoulder and Hand (QuickDASH-NP). Materials and methods The Nepali DASH and Shoulder Pain and Disability Index (SPADI) were completed at baseline assessment, and again at follow-up with the Nepali Global Rating of Change (GROC-NP) score. The 11 items of the QuickDASH-NP were extracted from the DASH and tested for confirmatory factory analysis (CFA), exploratory factor analysis (EFA), internal consistency (α), item-total correlation (ITC), test-retest reliability (ICC), measurement errors, hypothesis testing (correlation with DASH and SPADI) and responsiveness (effect size-ES, standardised response mean-SRM). Results A total of 156 participants completed questionnaires at baseline and 121 at follow-up with all questionnaires valid (no participant leaving more than one question blank). CFA suggested a poor fit for the single-factor model. The EFA demonstrated two factors with acceptable internal consistency (α = 0.79 and 0.75) for each factor. The test-retest reliability was excellent (ICC = 0.94; 95%CI:0.92–0.98), correlation was positive and very strong with the DASH-NP (r = 0.96) and strong with the SPADI-NP (r = 0.81). The Standard Error of Measurement was 2.83 and Smallest Detectable Change 7.84/100. The ES and SRM were moderate to high. Conclusions The QuickDASH-NP is reliable, valid, and able to detect change in shoulder symptoms among Nepali participants. It offers a short, easy to complete self-reporting tool for clinical use and research.

Objectives A history of shoulder pain is common in swimmers and may influence scapular position, possibly increasing the risk of shoulder pain recurring. The aim of this study was to establish and compare bilateral static measures of scapular upward rotation in swimmers (14–20 years), some with a history of shoulder pain but all currently pain free, in two different elevated positions of shoulder abduction. Design Cross-sectional, observational study. Participants Eighty-five swimmers without current shoulder pain. Methods Scapular upward rotation position was measured on both shoulders using a digital inclinometer in 90° and 140° shoulder abduction. Descriptive statistics were calculated for degrees of scapular upward rotation in both shoulder positions. Differences between shoulders (dominant, non-dominant, history and no history of pain) were explored using one-way ANOVA and paired t tests. Results A large range of values for scapular upward rotation was found at both positions of shoulder abduction but there were no significant differences between the shoulders: with and without a history of shoulder pain for the dominant and non-dominant sides. Conclusions A history of shoulder pain and arm dominance did not influence scapular upward rotation position when measured in shoulder abduction in swimmers without current shoulder pain.

Objectives Optimal shoulder rotation range of motion (ROM) for swimming is unknown. The primary aim of this study was to examine shoulder rotation ROM in elite swimmers, including the influence of humeral torsion on rotation ROM, in order to establish optimal shoulder rotation parameters for swimming. In addition, we examined the relationship between rotation ROM and shoulder pain. Design Descriptive cohort study. Methods Seventy elite Australian swimmers provided shoulder pain history data prior to measurement of humeral torsion and passive and active shoulder rotation ROM. Repeated measure analyses of variance were used to investigate within and between participant differences for all variables. Associations between humeral torsion and rotation ROM were investigated using Pearson's correlation coefficient. Multiple regression analysis was utilised to examine the associations between rotation ROM and shoulder pain. Results Average humeral torsion angles of 27±10° (dominant side) and 31±10° (non-dominant side) were demonstrated in this elite swimming cohort. In general, increased humeral torsion was positively associated with increased internal rotation (IR) and decreased external rotation (ER) ROM. There were significant differences in both IR and ER ROM measured passively and actively (F 2,136 ≥93.1, p 2 =0.058; p=0.46). Conclusions Humeral torsion angle and passive shoulder IR ROM were similar while passive ER ROM was greater in elite swimmers compared to reported normal population values.

Background The Shoulder Pain and Disability Index (SPADI) is a 13-item shoulder-specific patient-reported outcome measure (PROM). The English version is easy to use and has demonstrated excellent measurement properties for both clinical and research settings. The availability of the SPADI in Nepali would facilitate shoulder research and enhance management of patients with shoulder pain in Nepal. Therefore, the purpose of this study was to translate and cross-culturally adapt the SPADI into Nepali (SPADI-NP) and evaluate its measurement properties. Methods The translation and adaptation process followed international guidelines. Participants completed SPADI-NP on two assessments (N = 150 at initial and 119 at follow-up assessment). A Nepali version of the Global Rating of Change score was completed at follow-up. Assessment of measurement properties included analysis of internal consistency (Cronbach’s α), minimal detectable change (MDC) with standard error of measurement (SEM), test-retest reliability (intraclass correlation coefficient; ICC), validity (factor structure, construct using Pearson’s correlation with the Disability of Arm and Hand [DASH]) and responsiveness (area under the curve; AUC) with minimal important change (MIC). Results Minor changes were integrated in the adaptation process to improve cultural relevance such as dress items. Items were largely loaded under two factors (pain and disability), internal consistencies were good for the pain construct (α = 0.82) and disability (α = 0.88) and test-retest reliability was excellent (pain = 0.89, disability = 0.96). MDC was 5.7 (out of 100) with SEM = 2.1. Strong associations with the DASH (r = 0.63 pain, r = 0.81 disability) demonstrated its construct validity. The AUC was 0.68 and MIC was 12.3 (out of 100). Conclusion The Nepali version of the SPADI demonstrated excellent reliability and validity. It can be used for the assessment of shoulder pain and disability in patients with shoulder pain in Nepal in both clinical practice and research.

Objectives Load is used to increasingly challenge muscle function and has been shown to increase muscle activity levels with no change in activation patterns during shoulder flexion, extension, adduction and rotation. However, the effect of load during shoulder abduction, a movement commonly used in assessment of shoulder dysfunction and to improve shoulder function, has not been comprehensively examined. Therefore, the purpose of this study was to determine if load influences shoulder muscle activation patterns and levels during scapular plane abduction in normal subjects. Design Experimental study. Methods Fourteen volunteers performed shoulder abduction in the scapular plane at 25%, 50% and 75% of maximum load. Eight shoulder muscles were investigated using a combination of indwelling and surface electromyographic recordings: middle deltoid, infraspinatus, subscapularis, supraspinatus, serratus anterior, upper and lower trapezius and rhomboid major. Results All muscles tested showed increasing average muscle activation levels with increasing load and strong correlations in the activation patterns between loads. Conclusions Increasing shoulder abduction load not only increases activity in middle deltoid but also in the rotator cuff (infraspinatus, subscapularis, supraspinatus) and axioscapular (serratus anterior, upper and lower trapezius, rhomboid major) muscles. The functional stabilising role of both the rotator cuff and axioscapular muscles is considered an important contribution to the increased activation levels in these muscle groups as they function to counterbalance potential translation forces produced by other muscles during shoulder abduction. The activation patterns of all shoulder muscle groups during abduction can be trained at low load and progressively challenged with increasing load.

Frozen shoulder (adhesive capsulitis) is a severe chronic pain condition that is not well understood and current treatment is suboptimal. In several other chronic pain conditions motor imagery and tactile acuity deficits are present, which are thought to represent associated neuroplastic changes. The aims of this study were to determine if motor imagery performance assessed by the left/right judgement task, and tactile acuity assessed by two-point discrimination, are altered in people with unilateral frozen shoulder. In this cross-sectional, prospective study eighteen adults diagnosed with frozen shoulder in a physiotherapy clinic setting completed a left/right judgement task, response times (RT) and accuracy for the left/right judgement task were determined. Next, tactile acuity over both shoulders was assessed with a novel, force-standardised two-point discrimination test. Results corresponding to the affected side were compared to the pain free shoulder, Left/right judgement task: mean RT (SD) corresponding to the affected shoulder was significantly slower than RT for the healthy shoulder (p = 0.031). There was no side-to-side difference in accuracy (p &gt, 0.05). Neither RT nor accuracy was related to pain/disability scores or duration of symptoms (p &gt, 0.05). Two-point discrimination: mean two-point discrimination threshold of the affected shoulder was significantly larger than the contralateral healthy shoulder (p &lt, 0.001). Two-point discrimination threshold was not related to pain/disability scores or pain duration (p &gt, 0.05), One explanation for these findings is altered sensorimotor processing and/or disrupted sensorimotor cortex representations of the affected shoulder. A case then exists for the use of treatments aimed at reversing these changes, training the brain to reduce chronic shoulder pain.

Because of its superficial location, surface electrodes are commonly used to record lower trapezius activity. Recent evidence, however, would suggest that surface electromyography is not a valid to record activity from other superficially placed shoulder muscles. Therefore, the aim of this study was to determine the validity of using surface electrodes to record lower trapezius activity. Ten asymptomatic subjects performed ramped isometric (0–100% maximum load) and dynamic (70% maximum load) shoulder tasks. Intramuscular electrodes were inserted into lower trapezius and rhomboid major. Surface electrodes were placed over lower trapezius around the intramuscular electrodes. Differences in the recorded activity of lower trapezius between surface and intramuscular electrodes were tested using a 2 factor repeated measures analysis of variance with factors: test and electrode type. Similarity in the recorded activity patterns between the two electrodes was tested using Pearson’s correlation coefficient (r). Results indicated that there was no difference in lower trapezius activity levels (p = 0.98) or activation patterns (r ≥ 0.74) recorded by the intramuscular and surface electrodes. The results of this study indicate that any potential crosstalk contamination in the surface electrode signal is having little influence on the recorded activity from lower trapezius and therefore, support the common practice of surface electromyography to investigate lower trapezius function.

Background: Implicit motor imagery performance is altered in a variety of chronic pain conditions, but it is not known whether this is the case in shoulder pain.Objectives: The aim of this study was to assess implicit motor imagery performance, using a valid and reliable shoulder left/right judgement task in people with shoulder pain.Design: Cross-sectional observational study.Methods: Participants with (n ¼ 369) and without (n ¼ 747) shoulder pain completed the shoulder left/right judgement task (LRJT). Response times (RT), accuracy were determined. Age, gender, hand dominance, current pain intensity, Shoulder Pain and Disability Index (SPADI) and pain duration recorded. Planned analysis included ANOVAs for current pain, RT and accuracy.Results: Gender and hand dominance distribution were similar between groups (p > 0.5). The shoulder pain participants were older, mean age (SD); 47(14)years, than the control group; 41(14)years, p < 0.01. Participants with shoulder pain were slower, mean RT(SD); 1809(746)ms than the controls; 1701(749)ms; p ¼ 0.02, but no different in accuracy, mean % (SD); 93.2(8.5)% to controls; 94.1(9.4)%; p ¼ 0.13. The differences in RT were resolved when age was entered as a covariate (p ¼0.83). Regression of the data from the shoulder pain group only found that current pain was positively related to RT (B ¼ 43.97) and negatively to accuracy (B ¼-0.70).Conclusions: Participants with shoulder pain do not demonstrate poorer implicit motor imagery performance than people who are pain-free. However, more intense shoulder pain is associated with poorer implicit motor imagery performance. We recommend further research utilising the LRJT in well-defined clinically homogenous groups, with verified pain severity, functional disability, and chronicity. Refereed/Peer-reviewed

The left/right judgment task (LRJT) is the most commonly used method of assessing motor imagery performance. Abnormally long response times are thought to reflect delayed processing of body/spatial representations, and poor accuracy is thought to reflect disrupted cortical proprioceptive representations or body schema. Slower and less accurate responses on the LRJT have been reported in a variety of chronic musculoskeletal pain conditions. To date, no systematic review of the literature has been conducted to assess if altered motor imagery performance as measured by the LRJT is characteristic of all chronic musculoskeletal pain conditions. Therefore, the aim of this study was to conduct a comprehensive systematic review and meta-analysis of the literature to answer the following question: Do people with chronic musculoskeletal pain have impaired left/right body part judgment? Twenty-five studies (2,266 participants) including a range of chronic pain populations who undertook an LRJT were identified from searches of 8 electronic databases from inception to March 2017. Results indicate that chronic musculoskeletal pain conditions affecting the limbs and face (P ≤.01) are associated with altered motor imagery performance as measured by the LRJT. Perspectives: This review synthesizes evidence of altered motor imagery performance using the LRJT across chronic musculoskeletal pain conditions. Consistent evidence was found for altered motor imagery performance in peripheral pain conditions, but evidence was less consistent for axial conditions. Treatment to restore a normal body schema may be beneficial in chronic limb and facial pain. Refereed/Peer-reviewed

Objectives To determine the relationship and predictive value of isometric shoulder strength in the development of shoulder pain in young swimmers. Design Prospective, cohort study. Methods Shoulder flexion, extension, external and internal rotation strength tests were performed in elevation on 85 swimmers (14–20 years; 48 females) without current shoulder pain using a hand-held dynamometer. Following testing, swimmers were emailed questionnaires to determine if significant shoulder pain developed within 24 months subsequent to testing. The differences between shoulders that did and did not develop pain and the predictive ability of shoulder strength and strength ratios were investigated using Mann Whitney U tests and receiver operating characteristic curves. Results Thirty-seven swimmers (47%) returned questionnaires and 18 reported shoulder pain. A comparison of individual shoulders (27 with pain reported and 47 without) determined that shoulder extension strength was lower and flexion:extension strength ratio was higher for male swimmers (n = 36 shoulders) who reported shoulder pain compared to those who did not (p = 0.04). The predictive value of extension strength was fair (0.72; p = 0.03) for males with a cut-off value for extension strength calculated at 13.5% body mass. There were no differences between the two groups in shoulder rotation strength, age, training hours or previous pain history. Conclusions Shoulder extension strength, a functional test for swimmers, was associated with and predictive of the development of shoulder pain in male swimmers. Low shoulder extension strength may be a risk factor for the development of shoulder pain in swimmers, proposing a direction for injury prevention and future investigation.

Introduction Falling when older is a major public health issue. There is compelling evidence to show that specific exercise programs can reduce the risk and rate of falls in community-dwelling older people. Another major health issue for older people living in the community is upper limb dysfunction, including shoulder pain. Home-based exercise programs appeal to some older people, due to their convenience. Research questions This trial aims to determine the effectiveness and cost-effectiveness of a home-based lower limb exercise program compared with a home-based upper limb exercise program to prevent falls and upper limb dysfunction among community-dwelling people aged 65+ years. Design Randomised, controlled trial. Participants and setting A total of 576 community-dwelling people will be recruited from the Illawarra and Shoalhaven regions of New South Wales, Australia. Intervention Participants will be randomised to either a home-based lower limb exercise intervention or a home-based upper limb exercise intervention. The lower limb program is designed to improve balance and strength in the lower limbs. The upper limb program is designed to improve upper limb strength and mobility. Participants will attend three group-based instruction sessions to learn and progress the exercises, and will be instructed to perform the exercises three times per week at home for 12 months. Outcome measures The two primary outcomes will be fall rates, recorded with monthly calendars for a 12-month period, and upper limb dysfunction, measured with the Disability of the Arm, Shoulder and Hand questionnaire. Secondary outcomes will include: lower limb strength and balance; shoulder strength and mobility; physical activity; quality of life; attitudes to exercise; proportion of fallers; fear of falling; and health and community service use. The cost-effectiveness of both exercise programs from a health and community service provider perspective will be evaluated. Analysis Negative binomial regression models will be used to estimate the between-group difference in fall rates. Modified Poisson regression models will be used to compare groups on dichotomous outcome measures. Linear regression models will be used to assess the effect of group allocation on the continuously scored measures, after adjusting for baseline scores. Two economic evaluations will be conducted: the first will assess cost-effectiveness of the lower limb program compared with the upper limb program; and the second will assess cost-effectiveness of the upper limb program compared with the lower limb program. Discussion If effective, the trial will provide a model for both upper limb and lower limb exercise programs that can be performed at home and implemented at scale to community-dwelling older adults.

Study Design Observational: cross-sectional study. Background Idiopathic frozen shoulder is a common cause of severe and prolonged disability characterised by spontaneous onset of pain with progressive shoulder movement restriction. Although spontaneous recovery can be expected the average length of symptoms is 30 months. Chronic inflammation and various patterns of fibrosis and contracture of capsuloligamentous structures around the glenohumeral joint are considered to be responsible for the signs and symptoms associated with frozen shoulder, however, the pathoanatomy of this debilitating condition is not fully understood. Objectives To investigate the feasibility of a muscle guarding component to movement restriction in patients with idiopathic frozen shoulder. Methods Passive shoulder abduction and external rotation range of motion (ROM) were measured in patients scheduled for capsular release surgery for frozen shoulder before and after the administration of general anaesthesia. Results Five patients with painful, global restriction of passive shoulder movement volunteered for this study. Passive abduction ROM increased following anaesthesia in all participants, with increases ranging from approximately 55°–110° of pre-anaesthetic ROM. Three of these participants also demonstrated substantial increases in passive external rotation ROM following anaesthesia ranging from approximately 15°–40° of pre-anaesthetic ROM. Conclusion This case series of five patients with frozen shoulder demonstrates that active muscle guarding, and not capsular contracture, may be a major contributing factor to movement restriction in some patients who exhibit the classical clinical features of idiopathic frozen shoulder. These findings highlight the need to reconsider our understanding of the pathoanatomy of frozen shoulder. Level of evidence Level 4.

Because of its superficial location surface electrodes are commonly used to record latissimus dorsi (LD) activity. Despite the fact that the recommended electrode placement is over the belly where LD is quite thin no studies have investigated the possibility of signal contamination from muscles lying deep to LD. Therefore, the aim of this study was to determine the validity of using surface electrodes to record activity from LD. Eight asymptomatic subjects performed ramped isometric (0-100% maximum load) and dynamic (70% maximum load) shoulder tasks. Intramuscular electrodes were inserted into LD and the adjacent erector spinae. Surface electrodes were placed over LD around the intramuscular electrodes. Results indicated that while there was no difference in activity level or activation pattern (ICC0.94) recorded by the two electrode types during shoulder tasks in which LD would be expected to be active (extension and adduction), significantly lower (p0.05) LD activity was recorded via intramuscular electrodes during the shoulder flexion and abduction tasks. Therefore, recordings of LD activity by surface electrodes overestimate LD activity during shoulder tasks when this muscle would be expected to be activated at minimum levels. Erector spinae immediately deep to LD was confirmed as a source of crosstalk contamination.

Introduction Adhesive capsulitis (AC), also called frozen shoulder, is commonly diagnosed clinically and characterized by a global reduction of passive ranges of movement without radiographic abnormality. However, due to the effect of muscle spasm and pain, and other pathologies causing similar restriction of movements, the clinical diagnosis of AC can be challenging. Only invasive imaging procedures such as arthrography and arthroscopy have been shown to provide a definitive diagnosis for AC. Recent Magnetic Resonance Imaging studies(1-3) and ultrasound imaging studies (4-6) have shown a promising sign of an increased thickness of the inferior glenohumeral capsule (IGHC) in patients with AC. However the sensitivity and specificity of this finding using ultrasound in identifying patients with AC has not been established. Aim To establish the reliability of the increased thickness of IGHC on ultrasound in identifying patients with clinical signs of adhesive capsulitis. Methodology This study will include all volunteer participants (40-70 years of age) with unilateral shoulder problems referred for shoulder ultrasound scans. Active and passive ranges of movements (ROMs) will be measured. The images of the IGHC, the coracohumeral ligament (CHL) and rotator interval (RI) will be obtained bilaterally for comparison. Participants will be asked to return for follow up scans and for measurements of ROMs at 6, 12 and 24 month intervals. All other imaging results and clinicians’ diagnosis if available will be recorded. Data Analysis Participants with a global restriction of passive ROMs with at least 50% restriction in two planes, one of which is external rotation with no abnormality seen on the radiograph will be classified into a group clinically suggestive of AC. The specificity and sensitivity of the thickening of IGHC in identifying this group will be established. The thickness of CHL and vascularity in RI will also be analysed in this group. The duration of symptoms at the first visit will be taken into account and the changes of these structures over the time will also be analysed. Results As this study will incorporate both clinical / physical and imaging findings, it is anticipated that the results of this study have potential to aid in diagnosis and treatment of AC without the use of invasive procedures. Data collection will commence in March, and preliminary results will be presented.

Static optimization is commonly employed in musculoskeletal modeling to estimate muscle and joint loading; however, the ability of this approach to predict antagonist muscle activity at the shoulder is poorly understood. Antagonist muscles, which contribute negatively to a net joint moment, are known to be important for maintaining glenohumeral joint stability. This study aimed to compare muscle and joint force predictions from a subject-specific neuromusculoskeletal model of the shoulder driven entirely by measured muscle electromyography (EMG) data with those from a musculoskeletal model employing static optimization. Four healthy adults performed six sub-maximal upper-limb contractions including shoulder abduction, adduction, flexion, extension, internal rotation and external rotation. EMG data were simultaneously measured from 16 shoulder muscles using surface and intramuscular electrodes, and joint motion evaluated using video motion analysis. Muscle and joint forces were calculated using both a calibrated EMG-driven neuromusculoskeletal modeling framework, and musculoskeletal model simulations that employed static optimization. The EMG-driven model predicted antagonistic muscle function for pectoralis major, latissimus dorsi and teres major during abduction and flexion; supraspinatus during adduction; middle deltoid during extension; and subscapularis, pectoralis major and latissimus dorsi during external rotation. In contrast, static optimization neural solutions showed little or no recruitment of these muscles, and preferentially activated agonistic prime movers with large moment arms. As a consequence, glenohumeral joint force calculations varied substantially between models. The findings suggest that static optimization may under-estimate the activity of muscle antagonists, and therefore, their contribution to glenohumeral joint stability.

The physical mechanics of music making is important both in the prevention of injuries and in guiding how music is performed and taught. Electromyography has potential as a resource in understanding the loads involved in instrumental playing; however, only a small number of projects have been undertaken, and little is understood on the muscle activity used during bowing on string instruments. This study aimed to measure the muscle activity at the bowing shoulder of a cellist during cello playing and to establish if fine-wire EMG is useful in understanding muscle recruitment in string players without interfering with normal playing ability. This project used a combination of fine-wire and surface EMG to evaluate the muscular load placed on the right shoulder of a professional cellist whilst playing a set of various bowing exercises. The results indicated that different bowing techniques produced statistically different muscle activity levels, with the supraspinatus muscle in particular maintaining higher mean contraction (20% MVC) during all bowing patterns tested. Fine-wire EMG was useful in measuring shoulder muscle load and did not interfere with normal playing technique of the subject. Overall, the study presents a working protocol from which future studies may be able conduct further research.

Refereed/Peer-reviewed

Objectives: Open and closed-chain abduction of the shoulder are commonly used in rehabilitation and exercise programs to assess and/or improve shoulder muscle function. However, it is not known if shoulder muscle activation patterns differ between these two exercises. Therefore the purpose of this study was to compare muscle activation patterns during closed-chain shoulder abduction performed using a shoulder press machine with open-chain abduction using free weights. Design: Experimental study. Methods: Open and closed-chain abduction were performed by 15 and 14 subjects respectively at low (25%), medium (50%) and high (75%) load. Surface and indwelling electrodes were used to record the activation pattern of seven shoulder muscles during the concentric phase of each exercise. Data were normalised to maximum voluntary contractions (MVC), time normalised and compared over the common range of motion (40°–140° abduction). Results: Only the activation pattern of middle deltoid had a strong positive correlation between exercises (r ≥ 0.65, p < 0.05) with similar activation levels at all loads (35%, 50% and 60% MVC, p = 1.0). All other muscles tested had inconsistent, low or negative correlations between exercises. Significantly lower average activation levels were recorded during closed-chain abduction for subscapularis at all loads, upper trapezius at medium and high loads and infraspinatus and lower trapezius at high load (p < 0.05). Conclusions: Open-chain abduction is required to facilitate the stabilising role of the rotator cuff and axioscapular muscles, in response to middle deltoid activity. Closed-chain exercises may enable full range shoulder abduction earlier in rehabilitation programs, with an inherent stability and less demand on the rotator cuff.

The prevalence of shoulder pain in young swimmers is high. Shoulder rotation strength and the ratio of internal to external rotation strength have been reported as potential modifiable risk factors associated with shoulder pain. However, relative strength measures in elevated positions, which include flexion and extension, have not been established for the young swimmer. The aim of this study was to establish clinically useful, normative shoulder strength measures and ratios for swimmers (14-20 years) without shoulder pain.Cross-sectional, observational study.Swimmers (N=85) without a recent history of shoulder pain underwent strength testing of shoulder flexion and extension (in 140° abduction); and internal and external rotation (in 90° abduction). Strength tests were performed in supine using a hand-held dynamometer and values normalised to body weight. Descriptive statistics were calculated for strength and strength ratios (flexion:extension and internal:external rotation). Differences between groups (based on gender, history of pain, test and arm dominance) were explored using independent and paired t tests.Normative shoulder strength values and ratios were established for young swimmers. There was a significant difference (p0.002) in relative strength between males and females for all tests with no differences in strength ratios. Relative strength of the dominant and non-dominant shoulders (except for extension); and for swimmers with and without a history of shoulder pain was not significantly different.A normal shoulder strength profile for the young swimmer has been established which provides a valuable reference for the clinician assessing shoulder strength in this population.

Background: Disruption of cortically-held working body schema has been associated with a variety of pain conditions. A motor imagery technique - the left right judgement task (LRJT) - has been used as an indirect assessment of the integrity of the working body schema. To date there is no LRJT specifically designed to investigate the body schema of persons with shoulder pain. Objectives: To develop a shoulder specific LRJT and assess its validity and reliability. Design: Cross-sectional repeated measures. Methods: Shoulder images were developed representing the shoulder in a variety of postures of graded complexity/awkwardness and degree of rotation. These images were digitally mirrored to represent both left and right shoulders. Participants viewed the images on a computer and determined whether images were of a left or right shoulder. Results: 1413 participants were recruited worldwide and performed the shoulder LRJT (laterality judgement). Mean response time (SD) for the task was 1738(741) ms. Mean accuracy (SD) was 93.5(9.2)%. Chronbach's Alpha for shoulder image response times was 0.95. Participants were fastest responding to images of simple postures and slowest to images corresponding to the more awkward postures (mean difference 520 ms, 95%CI 469–570 ms). Participants were fastest responding to the least rotated images and slowest responding to inverted images, (mean difference 981 ms, 95%CI 919–1043 ms). Conclusions: The shoulder specific LRJT proved to be highly reliable. Response times increased with complexity and rotation of images, implying a motor imagery strategy was used to complete the task, validating the task as a measure of shoulder joint implicit motor imagery. Abnormal performance cut-offs for age were reported. This result will enable further research examining the relationship between shoulder pain and body schema. Refereed/Peer-reviewed

Objectives Although the belly press and lift off tests are recommended to assess subscapularis function, shoulder internal rotation (IR) exercises performed in other shoulder positions are more commonly used to restore subscapularis function. It is not known if shoulder IR exercises specifically activate subscapularis to the same degree as the lift off and belly press tests, and thus have the potential to effect subscapularis strength gains. Therefore, the aim was to compare subscapularis activation levels with those of other shoulder internal rotator muscles during the belly press and lift off tests and shoulder IR exercise positions. Design Original research. Methods Twenty asymptomatic volunteers performed maximal isometric contractions during the belly press and lift off tests and shoulder IR performed at 90° and 0° abduction in an upright position and supported at 90° abduction in supine. Muscle activation levels were recorded using a combination of indwelling and surface electrodes. Data were normalized to maximum voluntary contractions and averaged. Results Moderate average subscapularis activation levels were recorded during all shoulder IR tasks examined with no significant difference between tasks (p = 0.18). The belly press test was the only IR task in which subscapularis activation levels were significantly higher than all other shoulder internal rotator muscles (p Conclusions Shoulder IR exercises activate subscapularis to similar moderate levels as the belly press and lift off tests and therefore, have similar potential to strengthen subscapularis. However, the belly press test, with significantly higher subscapularis activation than other shoulder internal rotators, more specifically targets subscapularis.

Recent studies indicate that rotator cuff (RC) muscles are recruited in a reciprocal, direction-specific pattern during shoulder flexion and extension exercises. The main purpose of this study was to determine if similar reciprocal RC recruitment occurs during bench press (flexion-like) and row (extension-like) exercises. In addition, shoulder muscle activity was comprehensively compared between bench press and flexion; row and extension; and bench press and row exercises. Electromyographic (EMG) activity was recorded from 9 shoulder muscles sites in 15 normal volunteers. All exercises were performed at 20, 50 and 70% of subjects' maximal load. EMG data were normalized to standard maximal voluntary contractions. Infraspinatus activity was significantly higher than subscapularis during bench press, with the converse pattern during the row exercise. Significant differences in activity levels were found in pectoralis major, deltoid and trapezius between the bench press and flexion exercises and in lower trapezius between the row and extension exercises. During bench press and row exercises, the recruitment pattern in each active muscle did not vary with load. During bench press and row exercises, RC muscles contract in a reciprocal direction-specific manner in their role as shoulder joint dynamic stabilizers to counterbalance antero-posterior translation forces.

The four "Shoulder Normalization Tests" were found previously to be a parsimonious set of isometric tests that produce maximal voluntary isometric contractions (MVIC) in the supraspinatus, infraspinatus, subscapularis, trapezius, serratus anterior, deltoid, latissimus dorsi, and pectoralis major [Boettcher et al. (2008). J Orthop Res 26:1591-1597]. However, these tests have not been validated for rhomboid major and teres major. In the current study, these Shoulder Normalization Tests were evaluated and compared to three other tests that could possibly elicit maximum activity in rhomboid major and teres major: abduction/extension in 90° abduction; adduction at 90° abduction; and extension in 30° abduction. No statistical difference was found in the mean activation of rhomboid major and teres major in these additional MVIC tests compared to the Shoulder Normalization Tests. However, the extension MVIC test produced maxima for at least 50% of subjects in rhomboid major, teres major, and latissimus dorsi. We concluded that the original Shoulder Normalization Tests should be expanded to include the extension MVIC test. The EMG normalization reference value for any of the above muscles would be the maximum EMG level generated across these Revised Shoulder Normalization Tests.

Background: Passive mobilization of shoulder region joints, often in conjunction with other treatment modalities, is used for the treatment of people with shoulder pain and minimal movement restriction. However, there is only limited evidence supporting the efficacy of this treatment modality. Objective: The purpose of this study was to determine whether passive mobilization of shoulder region joints adds treatment benefit over exercise and advice alone for people with shoulder pain and minimal movement restriction. Design: This was a randomized controlled clinical trial with short-, medium- and longer-term follow-up. Setting: The study was conducted in a metropolitan teaching hospital. Patients: Ninety-eight patients with shoulder pain of local mechanical origin and minimal shoulder movement restriction were randomly allocated to either a control group (n=51) or an experimental group (n=47). Intervention: Participants in both groups received advice and exercises designed to restore neuromuscular control at the shoulder. In addition, participants in the experimental group received passive mobilization specifically applied to shoulder region joints. Measurements: Outcome measurements of shoulder pain and functional impairment, self-rated change in symptoms, and painful shoulder range of motion were obtained at 1, 3, and 6 months after entry into the trial. All data were analyzed using the intention-to-treat principle by repeated-measures analyses of covariance. Results: No statistically significant differences were detected in any of the outcome measurements between the control and experimental groups at short-, medium-, or longer-term follow-up. Limitations: Therapists and participants were not blinded to the treatment allocation. Conclusion: This randomized controlled clinical trial does not provide evidence that the addition of passive mobilization, applied to shoulder region joints, to exercise and advice is more effective than exercise and advice alone in the treatment of people with shoulder pain and minimal movement restriction.

Introduction Two potentially career ending injuries were reported in sonographers from work practices in the Western NSW Local Health District (WNSWLHD) in 2015. A subsequent Health and Safety investigation revealed that 95% of sonographers had musculoskeletal pain they attributed to work and 85% reported upper limb pain, data which was comparable to global trends. According to the literature, one in five sonographers will suffer from a career ending injury and around 80-90% of sonographers scan in pain. The most commonly reported area of pain is the right shoulder. There appears to be a paucity of high quality studies investigating potential solutions despite multiple surveys detailing the health problem. Methods A systematic review, registered with PROSPERO1, was conducted as part of higher research degree. Results Initial literature searches identified very few studies involving sonography populations. To gain further data, the review authors decided to include studies from other health professional occupations with similar postural upper limb workloads that show comparable upper limb musculoskeletal pain and dysfunction data. The comprehensive literature search yielded 26 full paper publications from 1526 potential articles after abstract and full text screening. Included studies researched the effect of an ergonomic intervention on upper limb pain in sonographers, or other health professional occupations with related postural upper limb workloads such as dentists or surgeons. Environmental ergonomic interventions were the most commonly studied for their effect on reducing upper limb pain. Currently, data on the impact of administrative and individual ergonomic interventions in the relevant populations is lacking. No meta -analysis was performed due to the heterogeneity of the studies. Conclusion Only 2 of 26 articles featured sonographers as a population, highlighting the urgent need for more robust clinical trials in this high risk occupation. 1. ‘The effectiveness of ergonomic interventions in reducing upper limb work- related musculoskeletal pain and dysfunction in sonographers and other health professions with related postural upper limb workloads. A systematic review.'

This preliminary study aimed to quantify the magnitude of the peak shoulder distraction force during the bowling action of female cricket fast bowlers. An eight camera Vicon motion analysis system operating at 120 Hz recorded the fast bowling actions of 18 Australian female fast bowlers. A three segment inverse solution model of the bowling arm was used to calculate the shoulder distraction force. A large peak shoulder distraction force was recorded during the early stages of the follow-through of the bowling action. When normalized for body weight, the distraction force was within the range of values reported for baseball and softball pitchers, who are considered to be at high risk of shoulder injury. Therefore, the relative importance of the peak shoulder distraction force in the fast bowling action for the development of shoulder pain in female cricket fast bowlers warrants further investigation.

The amount of torsion in the humerus is determined by both genetic and activity-related factors, and affects the external rotation range of motion available at the shoulder. Previous research has shown athletes participating in throwing sports to have a greater amount of humeral retrotorsion in their dominant arm. The purpose of this study was to investigate the predictive ability of both the genetic and activity-related aspects of humeral torsion regarding throwing-related injury. The amount of humeral torsion in both arms of 35 high level adolescent male baseballers (mean age 16.6 years+/-0.6 years) was measured at study commencement. Significantly increased humeral retrotorsion in the dominant arm compared to the non-dominant arm was found (p=0.04). These athletes were followed for a period of 30 months, and any injury to their throwing arm which resulted in missing either a game or practice was recorded. ROC curve analysis was used to determine the predictive ability of humeral torsion with respect to the occurrence of injury to the throwing arm. Of the 35 athletes, 19 suffered a throwing arm injury. AUC values derived from ROC analysis showed humeral torsion in the non-dominant arm (AUC: 0.679, 95% CI: 0.502-0.857), as well as the average of the humeral torsion in both arms (0.692, 0.512-0.873), to be predictive of injury. Torsion in the dominant arm was not a significant throwing arm injury predictor. Thus non-dominant arm humeral torsion (the genetic contribution) was found to be the predictor of throwing arm injury.

Question: During isometric shoulder adduction in normal subjects, do the rotator cuff muscles activate more than other shoulder muscles? Are the activation patterns influenced by shoulder abduction angle or load? Design : A within-participant, repeated measures experimental study. Participants: 15 healthy adults. Intervention: Participants performed an isometric adduction exercise at 30°, 60°, and 90° abduction in the scapular plane and at 25%, 50%, 75%, and 100% load. Outcome measures: During the exercises, a combination of indwelling and surface electromyographic recordings were taken from 11 shoulder muscles: supraspinatus, infraspinatus, subscapularis, pectoralis major, teres major, latissimus dorsi, rhomboid major, serratus anterior, lower trapezius, upper trapezius, and deltoid. Results: At 100% load, mean rotator cuff activation levels were low (supraspinatus at 3% of its maximum voluntary contraction, infraspinatus 27%, and subscapularis 27%) and significantly less than the activation levels of rhomboid major (81%), latissimus dorsi (103%), and teres major (76%) (F 10,140 = 15.5, p 0.89). Among the muscles activated above minimum levels (> 10% of maximum voluntary contraction), mean activation levels increased as load increased (F 3,42 = 72.0, p < 0.01) Conclusion: Since isometric adduction in normal subjects does not produce moderate to high activation levels in any of the rotator cuff muscles tested, these results do not support the use of shoulder adduction to identify rotator cuff muscle dysfunction or strengthen the rotator cuff muscles. [Reed D, Halaki M, Ginn K (2010) The rotator cuff muscles are activated at low levels during shoulder adduction: an experimental study. Journal of Physiotherapy 56: 259–264]

Based on previous electromyographic studies the 'empty can' (EC) and 'full can' (FC) tests have been promoted as being able to isolate activity to supraspinatus and are therefore diagnostic of supraspinatus dysfunction. However, there is evidence to suggest that these positions do not selectively activate supraspinatus, and that they may have poor diagnostic accuracy, bringing into question the validity of these tests. Due to limitations in the original EMG papers describing the EC and FC tests the current study aimed to further examine shoulder muscle activity during these tests to determine their ability to selectively activate supraspinatus. EMG activity was recorded from 13 muscles in 15 normal subjects while performing these two tests. Results showed that during the EC and FC muscle tests nine and eight other shoulder muscles, respectively, were equally highly activated as supraspinatus. It was concluded from these results that the EC and FC tests do not primarily activate supraspinatus with minimal activation from other shoulder muscles and therefore, do not satisfy basic criteria to be valid diagnostic tools for supraspinatus pathology. Therefore, these tests should not be interpreted as definitive tests for the clinical diagnosis of supraspinatus pathology. They may, however, be beneficial during shoulder muscle strengthening programs.

Objectives To determine the relationship between the amount of humeral torsion and a measure of active proprioception in adolescent male throwing athletes. Design Cross-sectional laboratory study with uninjured subjects. Setting University of Sydney and NSW Institute of Sport. Participants Participants were 16 adolescent male baseball players (15.0–18.1 years old, SD=16.3) holding baseball scholarships at the NSW Institute of Sport. Main outcome measures The main outcome measures, active proprioception (shoulder rotation, in 90° of arm abduction moving towards external rotation, using the Active Movement Extent Discriminating Apparatus) and humeral torsion (using an ultrasound-assisted method), were measured bilaterally. Results A strong ( r =0.88) and significant ( p =0.001) correlation was found between increasing humeral retrotorsion and better active proprioceptive acuity in the non-dominant arm, while the relation was weaker ( r =0.41) and did not reach statistical significance ( p =0.120) for the dominant arm. Conclusions A cognitive processing capacity model, which suggests that greater humeral retrotorsion reduces neural processing requirements, has been proposed to explain the direct relationship between proprioceptive acuity and humeral retrotorsion.

A comparison of electromyographic (EMG) activity of muscles between and within subjects, and during separate occasions of testing, requires normalization. The most common way for generating the reference level used for normalizing shoulder EMG data is with a maximum isometric voluntary contraction (MVIC). The purpose of this study was to develop a parsimonious set of standardized tests that generate an MVIC in all the major muscle groups of the shoulder. Twelve muscles of the dominant shoulder of 15 subjects were examined using a combination of surface and intramuscular electrodes during 15 tests. The results indicated that many tests maximally activated more than one muscle simultaneously. Four tests were identified as being sufficient for generating an MVIC in the 12 muscles examined and are recommended as the standard set for normalizing shoulder muscle EMG: abduction 90° with internal rotation (“empty can”), internal rotation in 90° abduction (“internal rotation 90°”), flexion at 125° with scapula resistance (“flexion 125°”), and horizontal adduction at 90° flexion (“palm press”). The use of these shoulder normalization tests will make comparisons between shoulder EMG studies more reliable. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

Objectives To determine the career history of low back pain (LBP) in current elite female cricket fast bowlers and then compare measures of lumbar spine and hip range of motion (ROM) and trunk extensor endurance between those bowlers with and without a history of LBP. Measures for the female bowlers were also compared to a small sample of male fast bowlers. Participants Twenty-six elite female fast bowlers and eight male fast bowlers of similar age and bowling experience. Main outcome measures The career history of LBP was determined by a self-administered questionnaire and by accessing medical records. Range of motion measures for the lumbar spine and hips were obtained using inclinometry or goniometry. Trunk extensor endurance was assessed using a modified Sorensen test. Results Fourteen female fast bowlers had a history of LBP. There was a significant difference in lumbar lateral flexion ROM to the bowling arm side between those female fast bowlers with and without a history of LBP ( p ⩽0.05). The female fast bowlers had significantly more bilateral hip extension ROM ( p ⩽0.05) compared to the male fast bowlers. Conclusions This information should be useful for practitioners involved in the conditioning and rehabilitation of cricketers. Future prospective studies should investigate potential predictors of LBP in female fast bowlers.

Study design Observational laboratory study. Background Abduction is a movement commonly used in the assessment of shoulder dysfunction and prescription of exercises to improve shoulder function. Abduction in the scapular and coronal planes are used interchangeably. It is not known if the activation of individual shoulder muscles differ between abduction performed in these planes and therefore, if they represent different tests/exercises. Objective To quantify and compare the muscle activation patterns and levels for each shoulder muscle during abduction performed in the scapular plane with that performed in the coronal (scapular −30°) and scapular +30° planes. Methods Electromyographic recordings were taken from eight shoulder muscles of fourteen healthy volunteers during shoulder abduction in the scapular and coronal planes and in a plane 30° anterior to the scapular plane (scapular +30°) at 50% of maximum load. Results Similar average muscle activation levels were demonstrated during abduction in the scapular plane and within a 30° arc of this plane for all muscles except: middle deltoid (5% MVC higher activation in the coronal and 4% MVC lower activation in the scapular +30° plane) and upper trapezius (6% MVC lower activation in the scapular +30° plane). Activation patterns between planes for all muscles were similar (ICC (3,1) ≥ 0.87). Conclusions Abduction can be performed within a 30° arc of the scapular plane with no change in shoulder muscle activation patterns. Only middle deltoid activation levels change between the scapular and coronal planes and middle deltoid and upper trapezius between the scapular and scapular +30° planes.

Background and Purpose Graduated rotation exercises performed with the arm by the side are commonly used to improve rotator cuff (RC) muscle function. The aim of this study was to compare the pattern of recruitment of the RC muscles with that of other shoulder muscles that rotate the shoulder joint during these exercises. Subjects The nondominant shoulders of 15 subjects who were healthy were tested. Methods Activity in the infraspinatus, supraspinatus, subscapularis, latissimus dorsi, pectoralis major, and posterior deltoid muscles was recorded. Low-, medium-, and high-intensity rotation exercises were performed with a pulley system. Results As the intensity of both internal and external rotation exercises increased, activity increased in a systematic manner in all muscles capable of producing rotation torque during concentric and eccentric contractions. Discussion and Conclusion The results indicate that, in people who are healthy, the motor strategy used to deal with increasing rotation resistance with the arm in a pendant position is to gradually increase activity in all shoulder rotation torque-generating muscles.

Precise muscle co-ordination is required to maintain normal shoulder function and alterations in synchrony between shoulder muscles can result in loss of full range of movement and pain. Although shoulder pain in kayakers is high with 53% of elite international paddlers reporting shoulder injuries, little information is available regarding the pattern of shoulder muscle recruitment during paddling. The aim of this study was to investigate the normal recruitment pattern of shoulder muscles during the kayak stroke. Nine recreational paddlers without shoulder pain were examined. EMG data from eight shoulder muscles of the dominant arm were collected simultaneously with video data during simulated paddling on an ergometer. EMG data was normalized to time and peak amplitude. Intersubject consistency was evaluated using Pearson correlation analysis. The results of this study indicated a fair to high correlation in at least one phase of the kayak stroke in five of the muscles examined: upper trapezius, supraspinatus, latissimus dorsi, serratus anterior and rhomboid major. This normative data will enable comparisons with the shoulder muscle recruitment patterns in kayakers with shoulder pain in order to determine the role of altered motor control in the painful kayaking shoulder.

Context: The reliable measurement of shoulder strength is important when assessing athletes involved in overhead activities. Swimmers' shoulders are subject to repetitive humeral elevation and consequently have a high risk of developing movement-control issues and pain. Shoulder-strength tests performed in positions of elevation assist with the detection of strength deficits that may affect injury and performance. The reliability of isometric strength tests performed in positions of humeral elevation without manual stabilization, which is a typical clinical scenario, has not been established. Objective: To establish the relative and absolute intrarater reliability of shoulder-strength tests functional to swimming in 3 body positions commonly used in the clinical setting. Design: Repeated-measures reliability study. Setting: Research laboratory. Subjects: 15 university students and staff (mean ± SD age 24 ± 8.2 y).Intervention: Isometric shoulder-strength tests were performed in positions of humeral elevation (flexion and extension in 140° abduction in the scapular plane, internal and external rotation in 90° abduction) on subjects without shoulder pain in supine, prone, and sitting. Subjects were tested by 1 examiner with a handheld dynamometer and retested after 48 h. Main Outcome Measures: Relative reliability (ICC3,1) values with 95% CI. Absolute reliability was reported by minimal detectable change (MDC). Results: Good to excellent intrarater reliability was found for all shoulder-strength tests (ICC .87-.99). Intrarater reliability was not affected by body position. MDC% was Conclusions: Shoulder flexion, extension, and internal- and external-rotation strength tests performed in humeral elevation demonstrated excellent to good intrarater reliability regardless of body position. A strength change of more than 15% in any position can be considered meaningful.

Accurate clinical interpretation of shoulder rotation range requires knowledge of the contribution of humeral torsion. This study compares the reliability of indirectly measuring humeral torsion using ultrasound visualisation with direct palpation and compares the degree of humeral torsion in a non-throwing adult population with a population of elite adolescent baseballers. The reliability of a novel method of indirectly measuring humeral torsion using palpation and ultrasound was established prior to using the ultrasound method to determine the amount of humeral torsion in both humeri of a group of 16 non-throwing subjects and 36 elite adolescent baseball players. Excellent inter-tester reliability was found for the ultrasound method of measuring humeral torsion in each arm (ICC 2,1: 0.98 and 0.94) but poor reliability for the direct palpation method (ICC 2,1: 0.51 and 0.49). Using the ultrasound method, side-to-side differences in humeral torsion ranged from 0 to 13 degrees for the non-throwing group and 0 to 29 degrees for the baseball players. This side-to-side difference was significant in the baseball players (p

Ginn KA, Cohen ML. Conservative treatment for shoulder pain: prognostic indicators of outcome. Arch Phys Med Rehabil 2004;85:1231–5. Objectives To investigate the long-term clinical outcome and to identify factors that predict that outcome, after conservative treatment of patients who have shoulder pain with or without accompanying stiffness. Design Cohort study. Setting Outpatient clinic. Participants Eighty-two subjects who had participated in a randomized controlled trial that compared the short-term effectiveness of conservative treatment for chronic, unilateral shoulder pain of mechanical origin with and without accompanying stiffness, and who were available for longer term follow-up 6 months after the cessation of formal treatment. Interventions Conservative treatment consisting of various combinations of exercise therapy, passive joint mobilization, electrophysical modalities, and corticosteroid injections. Main outcome measures Pain intensity, functional limitation, perceived change in symptoms, active range of motion, muscle force, and clinical and demographic variables. Results Patients showed significant improvement in all outcome measurements in the long-term whether or not their shoulder pain was accompanied by stiffness. Long-term outcome was not predicted by hand dominance, clinical history of the shoulder condition, severity of the shoulder problem, or shoulder mechanics. Conclusions Patients with chronic shoulder pain, with or without accompanying stiffness, can expect significant decreases in shoulder pain and improvements in shoulder function in the long term after conservative treatment.

PURPOSE: Shoulder pain is a common disorder. Despite growing evidence of the importance of physiotherapy, in particular active exercise therapy, little data is available to guide treatment. The aim of this project was to contribute to the development of an internationally accepted assessment and treatment algorithm for patients with shoulder pain. METHODS: Nine physiotherapists with expertise in the treatment of shoulder dysfunction met in Sweden 2012 to begin the process of developing a treatment algorithm. A questionnaire was completed prior to the meeting to guide discussions. Virtual conferences were thereafter the platform to reach consensus. RESULTS: Consensus was achieved on a clinical reasoning algorithm to guide the assessment and treatment for patients presenting with local shoulder pain, without significant passive range of motion deficits and no symptoms or signs of instability. The algorithm emphasises that physiotherapy treatment decisions should be based on physical assessment findings and not structural pathology, that active exercises should be the primary treatment approach, and that regular re-assessment is performed to ensure that all clinical features contributing to the presenting shoulder pain are addressed. Consensus was also achieved on a set of guiding principles for implementing exercise therapy for shoulder pain, namely, a limited number of exercises, performed with appropriate scapulo-humeral coordination and humeral head alignment, in a graduated manner without provoking the presenting shoulder pain. CONCLUSION: The assessment and treatment algorithm presented could contribute to a more formal, extensive process aimed at achieving international agreement on an algorithm to guide physiotherapy treatment for shoulder pain.

Background Shoulder instability is a common problem affecting young adults. Stabilization surgery followed by physiotherapy rehabilitation has been shown to reduce the chance of further episodes of shoulder dislocation and to improve quality of life in patients who sustain a shoulder dislocation as a result of a high collision trauma, but it is unclear if surgical intervention is beneficial for patients with atraumatic shoulder instability who have structural damage at the shoulder. The aim of this randomized controlled clinical trial is to determine if the addition of surgical intervention to physiotherapy rehabilitation improves outcomes for patients with atraumatic shoulder instability who have sustained soft tissue damage at their joint. Methods/Design 140 participants will be recruited. Patients with feelings of insecurity (apprehension) at their shoulder joint, which is not the result of a collision injury, with physical signs of shoulder joint instability will be invited to participate. Consenting participants will undergo arthroscopic investigation of the shoulder joint. Patients with capsulolabral damage will be randomly allocated using a concealed allocation procedure to either stabilization surgery immediately following the arthroscopic examination or no additional surgical procedure. All participants will then receive the same postoperative physiotherapy protocol for up to 6 months. Outcomes (pain, functional impairment and number of shoulder dislocations sustained) will be evaluated prior to surgery and, together with participant-reported improvement, again at 6, 12 and 24 months after randomization. The primary endpoint will be pain and functional impairment at 2 years. Participants, clinical staff (but not surgeons) and assessors will be blind to whether stabilization surgery was performed. Data analysis will be conducted on an intention-to-treat basis with the focus on estimation of the effect. Discussion This trial will have a direct and immediate impact on clinical decision making by establishing if patients presenting with soft tissue shoulder damage associated with atraumatic shoulder instability should be referred for stabilization surgery before commencing physiotherapy rehabilitation in order to ensure optimal outcome. This in turn will ensure effective, efficient use of scarce health resources to manage this common often disabling musculoskeletal condition. Trial registration Study was registered with National Institutes of Health Clinical Trials Protocol Registration System in December 2012. ClinicalTrials.gov Identifier: NCT01751490.