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OCCUPATIONAL APPLICATIONS This study found that dental hygienists are exposed to higher shoulder elevation angles when treating a simulated big-girth patient versus a simulated average-girth patient. These differences in motion patterns may increase dental hygienists’ susceptibility to shoulder musculoskeletal disorders. Ergonomic interventions may be needed to facilitate solutions to problems associated with treating patients who are overweight or obese. Ergonomics and human factors practitioners should educate dental hygienists to be more aware of their body posture, specifically shoulder position, while working on patients with big chest girth. TECHNICAL ABSTRACT Background: Dental hygienists suffer from musculoskeletal disorders of the upper extremities, and the prevalence of these disorders increases with years of occupation. Furthermore, the prevalence of overweight and obese individuals in the United States has been rapidly increasing for both adults and children in recent years. This may increase ...

Elastic taping is widely used in sports medicine for correcting functional alignment and muscle recruitment. However, evidence regarding its influence on scapular dynamic positioning is scarce. This study aimed to investigate the effect of a specific kinesiotaping method on scapular kinematics in female elite handball players without shoulder complaints. 25 athletes (18.0±1.5 years) active in the highest national division were recruited. All subjects received an elastic adhesive tape (K-active tape©) with the purpose to correct scapular position. 3-dimensional scapular motion measurements were performed (Fastrak®) during humeral elevation in the sagittal, frontal and scapular plane. The results showed that taping has a moderate to large effect (Cohen's d0.7) towards scapular posterior tilting, in all 3 planes of humeral movement and for all angles of elevation (mean posteriorizing effect of 4.23 °, 3.23 ° and 4.33 ° respectively for elevation in the sagittal, frontal and scapular plane, p0.001). In addition, taping also moderately increased the scapular upward rotation at 30 °, 60 ° and 90 ° of humeral abduction (mean increase of 2.90 °, Cohen's d0.7). Together these results suggest that kinesiotape application causes positive changes in scapular motion. This could support its use in sports medicine for preventing shoulder problems in overhead athletes.

Context:The literature does not present a consistent pattern of altered scapular kinematics in patients with shoulder-impingement syndrome (SIS).Objectives:To perform meta-analyses of published comparative studies to determine the consistent differences in scapular kinematics between subjects with SIS and controls. In addition, the purpose was to analyze factors of the data-collection methods to explain the inconsistencies in reported kinematics. The results of this study will help guide future research and enable our understanding of the relationship between scapular kinematics and SIS.Evidence Acquisition:A search identified 65 studies; 9 papers met inclusion criteria. Sample sizes, means, and SDs of 5 scapular-kinematic variables were extracted or obtained from each paper’s lead author. Standard difference in the mean between SIS and controls was calculated. Moderator variables were plane of arm elevation, level of arm elevation (ARM) and population (POP).Evidence Synthesis:Overall, the SIS group had less scapular upward rotation (UR) and external rotation (ER) and greater clavicular elevation (ELE) and retraction (RET) but no differences in scapular posterior tilt (PT). In the frontal plane, SIS subjects showed greater PT and ER, and in the scapular plane, less UR and ER and greater ELE and RET. There was also greater ELE and RET in the sagittal plane. There was less UR at the low ARM and greater ELE and RET at the high ARM with SIS. Athletes and overhead workers showed less UR, while athletes showed greater PT and workers showed less PT and ER. The general population with SIS had greater ELE and RET only.Conclusions:Subjects with SIS demonstrated altered scapular kinematics, and these differences are influenced by the plane, ARM, and POP. Athletes and overhead workers have a different pattern of scapular kinematics than the general population. The scapular plane is most likely to demonstrate altered kinematics. These factors should be considered when designing futures studies to assess the impact of altered kinematics in patients with SIS.

Background Scapular orientation is highly dependent on axioscapular muscle function. This study examined the impact of neck muscle fatigue on scapular and humeral kinematics in participants with and without subclinical neck pain (SCNP) during humeral elevation. Methods Ten SCNP and 10 control participants performed three unconstrained trials of dominant arm humeral elevation in the scapular plane to approximately 120 degrees before and after neck extensor muscle fatigue. Three-dimensional scapular and humeral kinematics were measured during the humeral elevation trials. Results Humeral elevation plane angle showed a significant interaction between groups (SCNP vs controls) and trial (pre- vs post-fatigue) (p = 0.001). Controls began the unconstrained humeral elevation task after fatigue in a more abducted position, (p = 0.002). Significant baseline differences in scapular rotation existed between the two groups (Posterior/Anterior tilt, p = 0.04; Internal/External Rotation, p = 0.001). Discussion SCNP contributed to altered scapular kinematics. Neck muscle fatigue influenced humeral kinematics in controls but not the SCNP group; suggesting that altered scapular motor control in the SCNP group resulted in an impaired adaption further to the neck muscle fatigue.

Background Short malunion of the clavicle after fracture can change scapular kinematics and alter clinical outcome. However, the effects of malunion on kinematics and outcomes remains poorly understood because there have been no in vivo studies measuring changes during active motion with malunion. This study aimed to measure and to compare in vivo 3-dimensional (3D) scapular kinematics between normal shoulders and shoulders with short malunion using 3D–2-dimensional model image registration techniques. Methods Fifteen patients with clavicle fracture who had been treated conservatively were enrolled in this study. In these patients, the angle of scapular upward rotation, posterior tilting, and external rotation were compared between shoulders with short malunion and contralateral, normal shoulders. A 3D–2-dimensional model image registration technique was used to determine the 3D orientation of the scapula. Results Scapular upward rotation increased following increase of the arm elevation angle and also showed a significant difference by arm elevation in both groups ( P = .04). Posterior tilting of the scapula gradually increased as the arm abduction angle increased, and this varied significantly between groups ( P = .01). Shoulders with short malunion also showed a more internally rotated position than the contralateral, normal shoulders between 100° and the maximum abduction angle ( P = .04). Conclusion Our results suggest that clavicle shortening of >10% greatly affects scapular kinematics in vivo. Further studies will be needed to determine the clinical implications of short malunion of the clavicle.

Stroke can lead to altered scapular motion that may limit the ability to perform activities of daily living. The aims were to evaluate scapular kinematics of individuals with chronic stroke and the correlation with paretic arm function.Scapular kinematics was assessed in thirty-four individuals (Chronic stroke=17; controls=17) during arm elevation and lowering in scapular and self-selected planes, and during hair combing. The use of the paretic arm to perform activities of daily living was assessed by the Motor Activity Log (MAL-30). Scapular kinematics was compared among paretic and non-paretic arms, and controls. Correlation between scapular kinematics and MAL-30 was also verified.Paretic and non-paretic arms showed increased scapular internal rotation (p0.05) during arm lowering in the scapular plane, and during arm elevation and lowering in the self-selected plane compared to controls. Increased internal rotation (p0.05) was also found in the paretic arm during hair combing compared to controls. Increased scapular anterior tilt (p0.05) was observed in the paretic arm during arm elevation while performing the activity of hair combing and during arm elevation and lowering in the scapular and self-selected planes compared to controls. The non-paretic arm showed increased anterior tilt (p0.05) during arm elevation and lowering in self-selected plane compared to controls. No difference in scapular upward rotation among neither arms, nor correlation between scapular kinematics and MAL-30 were found (p0.05).Individuals with chronic stroke showed bilateral scapular kinematics alterations. However, these alterations are not correlated with paretic arm function.

Recently, it has been suggested that sex may influence scapular kinematics. A more comprehensive analysis of the scapular kinematics in children and adults, including sex as a factor, will help to understand if differences between sexes are present since childhood. The purpose of this study was to compare scapular kinematics between sex in children and adults during elevation of the arm. One-hundred and sixteen asymptomatic adults (58 men and 58 women) and 53 children (28 boys and 25 girls) participated in the study. Three-dimensional scapular kinematics during elevation of the arm were obtained using an electromagnetic tracking device. Women had a more upwardly rotated scapula in the nondominant side (P < .05), with large effects and a more anteriorly tilted position at 60°, 90°, and 120° of arm elevation in the dominant side, and at 90° and 120° in the nondominant side (P < .05) with moderate effects when compared with men. Differences between sexes were not found in the children (P > .05). In conclusion, sex seems to influence scapular kinematics in adulthood, but not in childhood.

BACKGROUND: Subacromial pain syndrome (SAPS) and scapular dyskinesis are closely associated, but the role of pain is unknown. We hypothesized that pain results in asymmetrical scapular kinematics, and we expected more symmetrical kinematics after infiltration of subacromial anaesthetics. OBJECTIVE: To investigate the effect of subacromial anaesthetics on scapular kinematics in patients with SAPS. DESIGN: Observational cohort study. METHODS: We evaluated shoulder kinematics in 34 patients clinically and radiologically (magnetic resonance arthrography) identified with unilateral SAPS using three-dimensional electromagnetic motion analysis (Flock of Birds). Scapular internal rotation, upward rotation and posterior tilt of the affected shoulder were compared with the kinematics of the unaffected shoulder and following subacromial anaesthetics. Additionally, the association of pain (Visual Analogue Scale, VAS) and scapular rotation was analysed. RESULTS: Compared with the contralateral healthy shoulder, 5° more (95% CI 0.4-9.7, p = 0.034) scapular internal rotation was observed in the affected shoulder at 110-120° of abduction. Following subacromial anaesthetics in the affected shoulder, internal rotation increased (2°, 95% CI 0.5-3.9, p = 0.045) and posterior tilt decreased (3°, 95% CI 1.5-5.0, p = 0.001) at 110-120° of abduction. Less scapular upward rotation was significantly associated with higher pain scores before infiltration (R = 0.45, p = 0.013). CONCLUSIONS: More scapular internal rotation was observed in affected shoulders of patients with SAPS compared with unaffected shoulders. Subacromial infiltration did not restore kinematics toward symmetrical scapular motion. These findings suggest that subacromial anaesthesia is not an effective means to instantly restore symmetry of shoulder motion.

Background: Current non-invasive 3-D scapular kinematic measurement techniques such as electromagnetic tracking are subjected to restrictions of wired sensors and limited capture space. Video-based motion analysis provides greater freedom with relatively less movement restriction. However, videobased motion analysis was rarely used in and not validated for scapular kinematics. Methods: Scapular kinematics of five subjects performing abduction, scaption, and internal/external rotation was captured simultaneously with video-based motion analysis and dynamic stereo X-ray, a gold standard for tracking scapular movements. The data from video-based motion analysis was correlated with the data from dynamic stereo X-ray for validity evaluation. Findings: Strong and significant correlations were identified in scapular protraction/retraction and medial/lateral rotation during abduction and scaption, and scapular medial/lateral rotation and anterior/posterior tilt during internal/external rotation. Interpretation: Video-based motion analysis is valid for evaluating a single subject’s scapular movement pattern in protraction/retraction during abduction and scaption, and medial/lateral-rotation during internal/external rotation. Anterior/posterior-tilt during abduction and scaption should be investigated with caution. Video motion analysis is also valid for evaluating group average of scapular kinematics except for protraction/retraction during internal/external rotation. While acknowledging the inherent limitations, video-based motion analysis is an appropriate technique for tracking scapular kinematics. & 2012 Elsevier Ltd. All rights reserved.

Context:Shoulder injuries are common in swimmers because of the demands of the sport. Muscle imbalances frequently exist due to the biomechanics of the sport, which predispose swimmers to injury. To date, an effective shoulder-injury-prevention program for competitive swimmers has not been established.Objective:To assess the effectiveness of a 6-wk strengthening and stretching intervention program on improving glenohumeral and scapular muscle strength and scapular kinematics in collegiate swimmers.Design:Randomized control trial.Setting:University biomechanics research laboratory.Participants:Forty-four Division I collegiate swimmers.Interventions:The intervention program was completed 3 times per week for 6 wk. The program included strengthening exercises completed using resistance tubing—scapular retraction (Ts), scapular retraction with upward rotation (Ys), scapular retraction with downward rotation (Ws), shoulder flexion, low rows, throwing acceleration and deceleration, scapular punches, shoulder internal rotation at 90° abduction, and external rotation at 90° abduction—and 2 stretching exercises: corner stretch and sleeper stretch.Main Outcome Measurements:Scapular kinematics and glenohumeral and scapular muscle strength assessed preintervention and postintervention.Results:There were no significant between-groups differences in strength variables at pre/post tests, although shoulder-extension and internal-rotation strength significantly increased in all subjects regardless of group assignment. Scapular kinematic data revealed increased scapular internal rotation, protraction, and elevation in all subjects at posttesting but no significant effect of group on the individual kinematic variables.Conclusions:The current strengthening and stretching program was not effective in altering strength and scapular kinematic variables but may serve as a framework for future programs. Adding more stretching exercises, eliminating exercises that overlap with weight-room training and swim training, and timing of implementation may yield a more beneficial program for collegiate swimmers.

Dental hygienists suffer a high incidence of shoulder pathology that seems to increase with job longevity. It has been hypothesized that occupational injuries could be due to local muscle fatigue caused by repetitive low level work and awkward and constrained working postures. In the laboratory, scapular kinematics can be temporarily altered using fatiguing protocols. It is unknown whether or not workday fatigue causes changes to scapular kinematics. The aim of this study was to examine if changes in scapular tilt and rotation occurs after a workday in dental hygienists.The pre and post workday scapular kinematics were recorded from dental hygienists using an electromagnetic tracking system. All data were recorded within the place of employment of the dental hygienist.Following the workday, there was significantly more scapular anterior tilt in dental hygienists (P0.05); however, no changes were found for upward or internal rotation. Greater kinematic differences were found for hygienists with greater job longevity.The increase in scapular anterior tilting could be due to post workday fatigue. Anterior tilting of the scapula may have an influence on the development of subacromial impingement syndrome. Hygienists with greater duration of work experience may be at greater risk for developing shoulder injuries as they have more anterior tilting of the scapula post workday.

Background Scapular dyskinesis is an abnormal scapular motion or position during active arm elevation. Dyskinesis is theorized to contribute to impingement syndrome by decreasing the subacromial space. A corrective maneuver of the scapular assistance test (SAT) proposes to increase scapular upward rotation and posterior tilt to increase the subacromial space. The purpose of this study is to determine the influence that 1) scapular dyskinesis and 2) passive manual correction with the SAT have on subacromial space and 3-dimensional (3-D) scapular kinematics. Materials and methods Forty asymptomatic participants were classified with either obvious dyskinesis (n = 20) or normal motion (n = 20) using the scapular dyskinesis test. The anterior outlet of the subacromial space was measured via the acromiohumeral distance using ultrasound imaging and 3-D scapular orientation was assessed with electromagnetic motion analysis, with the arm at rest 45° and 90° of active elevation with and without the SAT, respectively. Results There were no differences in acromiohumeral distance or scapular kinematics with static active arm elevation between groups. The SAT increased scapular upward rotation, posterior tilt, and acromiohumeral distance in both groups. Participants with dyskinesis demonstrated greater scapular mobility in upward rotation with the SAT, but no additional increase in acromiohumeral distance. Conclusion Scapular dyskinesis identified during active motion did not result in different 3-D scapular orientation or acromiohumeral distance during active arm elevation in static positions; however, the SAT altered scapular kinematics and increased acromiohumeral distance. The SAT may be helpful to identify individuals where subacromial compression is producing symptoms, regardless of dyskinesis.

Background There have been few reports on altered kinematics of the shoulder after reverse total shoulder arthroplasty (RTSA). We investigated differences in 3-dimensional (3D) scapular motions assessed using an optical tracking system between RTSA treated shoulders and asymptomatic contralateral shoulders during arm motion. Methods Thirteen patients who underwent RTSA were assessed for active arm elevation in 2 distinct elevation planes (sagittal plane flexion and scapular plane abduction). Their mean age was 72 years (range, 69 to 79 years) and the mean follow-up was 24.4 months (range, 13 to 48 months). The dominant side was the right side in all the 13 patients, and it was also the side treated with RTSA. Scapular kinematics was recorded with an optical tracking system. The scapular kinematics and the scapulohumeral rhythm (SHR) of the RTSA shoulders and asymptomatic contralateral shoulders were recorded and analyzed during arm elevation. Results There were no significant differences in internal/external rotation and anterior/posterior tilting of the scapula between shoulders during arm motion (p > 0.05). However, upward rotation of the scapula differed significantly during arm motion (p = 0.035 for sagittal plane flexion; p = 0.046 for scapular plane abduction). There were significant differences in the SHR between the two shoulders (p = 0.016 for sagittal plane flexion; p = 0.021 for scapular plane abduction). Conclusions The shoulder kinematics after RTSA showed significant differences from the contralateral asymptomatic shoulders. Increased upward rotation and decreased SHR after RTSA indicate that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm.

Alterations in scapular motion frequently are seen in association with various shoulder disorders. It is common clinically to compare the pathological shoulder with the contralateral shoulder, in spite of arm dominance, to characterize the disorder. However, there have been few articles that test the underlying assumption that dominant and nondominant shoulders exhibit comparable dynamic kinematics. The purpose of this study was to compare the 3-dimensional (3-D) scapular kinematics of dominant and nondominant shoulders during dynamic scapular plane elevation using 3-D-2-D (2-dimensional) registration techniques.Twelve healthy males with a mean age of 32 years (range, 27-36) were enrolled in this study. Bilateral fluoroscopic images during scapular plane elevation and lowering were taken, and CT-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D-2-D registration techniques. Angular values of the scapula and scapulohumeral rhythm were compared between dominant and nondominant shoulders with statistical analysis.There was a significant difference in upward rotation angles between paired shoulders (P.001), while significant differences were not found in the other angular values and scapulohumeral rhythm. The dominant scapulae were 10° more downwardly rotated at rest and 4° more upwardly rotated during elevation compared to the nondominant scapulae.Scapular motion was not the same between dominant and nondominant arms in healthy subjects. The dominant scapula was rotated further downward at rest and reached greater upward rotation with abduction. These differences should be considered in clinical assessment of shoulder pathology.

Subacromial impingement syndrome (SAIS), which is associated with pain and a loss of function, has a high occurrence in the physically active population. Not all patients respond positively to treatment. Classifying patients can improve decision-making. The scapular kinematic and clinical impairments can aid in classifying the patients who are more likely to respond to physical therapy treatment. Thirty-three subjects (males, 20-33 years) presenting SAIS were studied to determine altered scapular kinematics and clinical impairments. Three measurements were collected: (1) three-dimensional scapular kinematics during performing functional tasks; (2) impairment outcomes of range of motion and muscle force; and (3) self-reported measurements of pain, satisfaction, and function. All patients received 6-week (2 times per week) physical therapy treatment. Improvement with treatment was determined using the Global Rating of Change Scale. Scapular kinematics and clinical impairments were first identified by t-test in predicting improvement and then combined into a multivariate prediction method. A prediction method with three variables (Flexilevel Scale of Shoulder Function score < 41, muscle power of serratus anterior < 27.4% body weight, degree of scapular internal rotation at 30° shoulder elevation during descending arm phase in unloaded condition

Introduction/Background To examine the effect of compensatory strategies training for patients with massive rotator cuff tear (MRCT). Material and method Twenty-four subjects with MRCT were recruited to participate three times shoulder assessments and 12 weeks of intervention. After initial assessment, the subjects were assigned randomly into two groups (CS-TE and TE-CS). CS-TE group was provided compensatory strategies (CS) training followed by 6 weeks of traditional exercise (TE) training. In comparison, TE-CS group took 6 weeks TE training followed by CS. All the participants were arranged to attend the second assessments after completing the first 6 weeks of intervention, and the third assessment at the end of 12 weeks of intervention, including measurements of visual analogue scale (VAS), range of motion (ROM) of shoulder, shoulder pain and disability index (SPADI) questionnaire, shoulder and scapular muscle strength. In addition, scapular kinematics analysis were performed at initial and 2nd assessments. Results After the first 6 weeks training, CS-TE group showed significant important in motion pain measurement, SPADI score, AROM and strength of local muscles at 6th week; however, TE-CS group only showed significant improvement in SPADI score and flexion of shoulder. Moreover, after 6 weeks of the CS training, TE-CS group showed significant improvement in VAS and strength of compensatory muscles and scapular muscles. Furthermore, significant improvements in scapular control strategies were only found in CS-TE group after completing 6 weeks of intervention, showing significantly increasing scapular external rotation (ER) and posterior tipping (PT). Conclusion Our results have supported that CS training is an effective treatment for establishing the compensatory strategies after MRCT and regaining the shoulder function by strengthening the humeral head depressors and scapular stabilizers.

Scapular position and motion are essential for normal upper limb mobility; Further, the posture of patients with thoracic kyphosis is related to shoulder girdle function and disorder. The purpose of this study was to examine the effects of thoracic posture on the shoulder range of motion and on three-dimensional scapular kinematics. Thirty healthy subjects performed right-arm abduction along the frontal plane while standing in both erect and in slouched trunk posture. The scapular position and rotation, and shoulder and thoracic angles were recorded using a motion analysis system. The scapular upward rotation and internal rotation were significantly altered according to postural tatiges; however, scapular tilt was not affected. Shoulder angle was significantly decreased in the slouched posture as c rpared to tatt in the erect posture. Thus, a slouched posture(thoracic kyphosis) significantly affects the shoulder range of motion and scapular kinematics during shoulder abduction in the frontal plane.

Hypothesis The scapulothoracic (ST) joint affects glenohumeral (GH) joint function. We observed 3-dimensional scapular motions during arm elevation and lowering to identify the scapulohumeral rhythm in healthy subjects and to compare it between the dominant and nondominant arms. Materials and methods Twenty-one healthy subjects participated in this study. Participants randomly elevated and lowered the arms in the scapular plane, and data were recorded by a computerized 3-dimensional motion analyzer at each 10° increment. Results Of the 42 shoulders, 21 showed a greater ratio of GH motion relative to ST motion whereas the other 21 showed a smaller ratio of GH motion relative to ST motion. The angle of upward rotation of the scapula showed a statistically significant difference between both types. The mean maximum angles of upward rotation, posterior tilting, and internal rotation were 36.2° ± 7.0°, 38.7° ± 5.7°, and 36.8° ± 12.2°, respectively. No significant difference was found in angles of 3 scapular rotations between the dominant and nondominant arms. Discussion These results indicate that there are 2 distinctly different scapulohumeral rhythms in healthy subjects but without a significant difference between dominant and nondominant arms. These findings should be referred to when one is interpreting kinematics in a variety of shoulder disorders.

Accurate measurement of the three-dimensional scapular kinematics is essential for a better understanding of the mechanical interactions between the scapula and the other segments of the shoulder complex. The purposes of the study were: (i) to development a marker-based scapular locator for measuring scapular poses, and (ii) to determine the intra- and inter-rater reliability of the locator in terms of intra-class correlations (ICC). Twenty-two healthy volunteers without shoulder pathologies participated in the current study. Each subject was tested separately by two raters using the marker-based scapular locator while performing static shoulder flexion at 20, 40, 60, 80, 100 and 120 degrees in the scapular plane. Two reliability models, ICC[Formula: see text] and ICC[Formula: see text], were used to analyze the intra- and inter-rater reliability for scapular rotations and translations. Good to excellent intra-user reliability for both examiners was found for the scapular rotations (range: 0.82–0.99) and displacements (range: 0.72–0.99) for different shoulder flexion conditions. Good to excellent inter-rater reliability was found for scapular rotations (range: 0.63–0.95) and translations (range: 0.70–0.95) for all conditions. The results showed that high intra- and inter-examiner reliability could be achieved for scapular rotations and translation using the marker-based scapular locator. The proposed new scapular locator with an optical tracking system will be helpful for future applications in basic and clinical studies of the shoulder complex during arm movements.

This was the third research meeting focused on scapular function and dysfunction, following similar meetings in 2003 and 2006. The purpose of this meeting, hosted by the Shoulder Center of Kentucky, was to continue to examine the biomechanical and clinical factors thought to be associated with the role of the scapula in shoulder function and dysfunction. Since the last Summit, much more information has been created in this area, and it was thought that enough progress had been made that an organized overview of current knowledge could provide some consensus statements to guide further research and provide assessment and treatment guidelines. A call for abstracts was extended to researchers with proven interest and published research on the scapula. The meeting was organized around 3 primary categories of information: scapular kinematics and dysfunction, clinical evaluation of the scapula, and interventions. The last session of the meeting involved development of consensus statements for each category. Thi...

Poor scapulothoracic control is a risk for developing shoulder pathology, but has received little attention so far in individuals with stroke (IwS). Trunk and scapular kinematics and surface muscle activity were measured in 15 healthy controls and 18 IwS during a low and high forward flexion (FF). Group-differences in trunk and scapular kinematics were assessed during low and high FF using a t-test (independent samples). Differences in muscle onset and offset time relative to movement start (both FF tasks) were determined using a mixed model taking into account the different groups and muscles. Recruitment patterns per group and task were described based on significant differences between muscles. In IwS, earlier lower trapezius and late infraspinatus offset were found during low FF, as well as a later onset and earlier offset of serratus anterior. For low FF, significantly more trunk axial rotation was found in IwS during both elevation and lowering. During high FF, IwS showed significantly less scapular posterior tilt during elevation and more scapular lateral rotation during lowering. IwS demonstrated adaptive muscle timing with earlier initiation and late inactivation of lower trapezius and infraspinatus, possibly to compensate for a late activation and early deactivation of the serratus anterior and to establish as such the correct pattern of scapulothoracic movement.

Objective To examine the effect of kinesiology tape (KT) on shoulder strength, proprioception, and scapular kinematics in healthy and Subacromial Impingement Syndrome (SAIS) subjects. Design Placebo-controlled quasi-experimental study. Setting Research laboratory. Participants A total of 30 physically active subjects participated. Ten healthy subjects with no previous history of shoulder pathology received KT on the dominant shoulder. Twenty subjects with shoulder pain for a minimum of two weeks and presenting with clinical signs of impingement were allotted to receive KT (n = 10) or placebo taping (PT, n = 10) on the involved shoulder. Main outcome measures All participants were tested pre- and post-application. Shoulder internal/external rotation (IR/ER) strength was assessed with isokinetic dynamometry (average peak torque/body weight). Shoulder IR/ER proprioception was assessed through threshold to detect passive motion (mean absolute error in degrees). Scapular position at 90° and 120° of shoulder abduction during arm raising/lowering were assessed using a 3D motion analysis system. Results No significant within group or between group differences were demonstrated for any measure. Conclusions Taping does not appear to aid/impair shoulder strength, shoulder proprioception, or scapular kinematics. Future research should explore if the effects of KT are time-dependent and similar in other pathologies.

Randomized controlled trial.To determine if thoracic spinal manipulative therapy (SMT) alters thoracic kinematics, thoracic excursion, and scapular kinematics compared to a sham SMT in individuals with subacromial impingement syndrome, and also to compare changes in patient-reported outcomes between treatment groups.Prior studies indicate that thoracic SMT can improve pain and disability in individuals with subacromial impingment syndrome. However, the mechanisms underlying these benefits are not well understood.Participants with shoulder impingement symptoms (n = 52) were randomly assigned to receive a single session of thoracic SMT or sham SMT. Thoracic and scapular kinematics during active arm elevation and overall thoracic excursion were measured before and after the intervention. Patient-reported outcomes measured were pain (numeric pain-rating scale), function (Penn Shoulder Score), and global rating of change.Following the intervention, there were no significant differences in changes between groups for thoracic kinematics or excursion, scapular kinematics, and patient-reported outcomes (P.05). Both groups showed an increase in scapular internal rotation during arm raising (mean, 0.9°; 95% confidence interval [CI]: 0.3°, 1.6°; P = .003) and lowering (0.8°; 95% CI: 0.0°, 1.5°; P = .041), as well as improved pain reported on the numeric pain-rating scale (1.2 points; 95% CI: 0.3, 1.8; P.001) and function on the Penn Shoulder Score (9.1 points; 95% CI: 6.5, 11.7; P.001).Thoracic spine extension and excursion did not change significantly following thoracic SMT. There were small but likely not clinically meaningful changes in scapular internal rotation in both groups. Patient-reported pain and function improved in both groups; however, there were no significant differences in the changes between the SMT and the sham SMT groups. Overall, patient-reported outcomes improved in both groups without meaningful changes to thoracic or scapular motion.Therapy, level 1b-.

Measurement of 3D scapular kinematics is meaningful in patients with shoulder pathologies showing scapular dyskinesis. This study evaluates the effect of single and double anatomical calibration (0° and 120°) with a scapula locator compared to standard calibration (using sensor alignment with the spina scapulae and static upright posture, ISEO-protocol) on 3D scapular kinematics measured with an inertial and magnetic measurement system (IMMS). Ten patients with scapular dyskinesis performed humeral anteflexion and abduction movements while 3D scapular kinematics were measured using IMMS sensors. The sensor on the scapula was anatomically calibrated (i) according to the ISEO-protocol, (ii) using single scapula locator calibration (0°) and (iii) double scapula locator calibration (0° and 120°). For calibration, the scapula locator (with IMMS) was positioned on the scapula, while holding the humerus at several anteflexion and abduction postures. Single and double calibration resulted in a significant increase of scapular anterior tilt (14–30°) with respect to the skin-fixed sensor (ISEO). Protraction angles were not significantly different. During anteflexion, double calibration did not show a significant increase in lateral rotation compared to single calibration. During abduction of >90°, double calibration showed 10–14° increased lateral rotation with respect to single calibration, although this was not significant (P>0.06). Calibration with a scapula locator when applying IMMS is necessary, because measures of scapular anterior tilt are grossly underestimated with the ISEO-protocol. For shoulder movements that exceed 90° elevation, a double calibration prevents small but relevant underestimation of lateral rotation angles of the scapula.

Shoulder tightness may cause altered kinematics and lead to development of subacromial impingement, tendinitis, and degenerative changes. In this investigation, the humeral head translations, scapular kinematics, and scapulohumeral rhythm were determined with a three-dimensional electromagnetic tracking device during arm elevations in six subjects with anterior shoulder tightness and in six subjects with posterior shoulder tightness to study the effects of anterior/posterior tightness on shoulder kinematics. Subjects with anterior tightness showed lower slopes in curves of glenohumeral elevation plotted against scapular upward rotation (scapulohumeral rhythm, 0.11 to 0.32; p = 0.021) and less posterior scapular tilt (2.9 to 7.5 degrees; p = 0.002) during arm elevations when compared to the group with posterior tightness. The humeral head was positioned less posteriorly (2.2 to 3.4 mm; p = 0.004) and more superiorly (3.8 to 7.0 mm; p < 0.0005) during arm elevation in subjects with posterior tightness. The alternations in shoulder kinematics between subjects with anterior and posterior shoulder tightness may be relevant to the development of subacromial impingement, tendinitis, and degenerative changes as seen in subjects with stiff shoulders.

Dissertação de Mestrado em Fisioterapia. Relatório de Projeto de Investigação Introdução: O Complexo articular do ombro é propício a várias patologias e disfunções do movimento que parecem estar relacionadas às alterações na orientação da omoplata. A literatura recentemente publicada enfatiza a necessidade de desenvolvimento de ferramentas clínicas medição da orientação da omoplata que sejam precisas e de fácil utilização. Objetivo: Contribuir para o desenvolvimento de um método clínico para medir a orientação da omoplata a 0º e 90º de elevação do ombro. Metodologia: Foi feito um estudo correlacional utilizando uma amostra de 20 participantes assintomáticos, selecionados por conveniência do corpo discente da ESS-IPS. Foram coletadas cinco medições lineares (M1, M2, M3, M4 e M5) por dois avaliadores independentemente em dois momentos diferentes entre as referências ósseas da coluna vertebral e da omoplata na elevação do braço a 0º e 90º no plano sagital, coronal e escapular. Foi coletada simultaneamente a orientação 3D da omoplata utilizando um dispositivo de varrimento eletromagnético (Flock of Birds) e o movimento reconstruído de acordo com as recomendações da Sociedade Internacional de Biomecânica. Resultados e Discussão: O valor das correlações entre medidas lineares e angulares da posição e orientação da omoplata foram definitos como de aceitáveis e moderados, sempre acima de 0,4 e 0,5, respectivamente. Com a elevação do MS a 0º no plano frontal, foram encontradas correlações estatisticamente significativas entre a rotação interna da omoplata com M2 e M5, e entre a rotação inferior da omoplata com M1, M3 e M4. No plano sagital, foram observadas correlações significativas entre a rotação interna da omoplata com M4, e da rotação superior da omoplata com M1 e M4. No plano da omoplata, encontraram-se correlações estatisticamente significantes entre a rotação interna da omoplata e M2 e da rotação inferior com M1. Na posição de 90º de elevação do MS, apenas M2 correlacionou-se significativamente com a rotação interna da omoplata. Conclusão: Estes resultados preliminares revelam uma promessa de um método clínico preciso e fácil de usar para quantificar a orientação da omoplata com base em medições lineares. Abstract: Introduction: The shoulder complex, is prone to several pathologies and movement dysfunctions that seem to be related to alterations in scapula orientation. Recent published literature emphasize the need for the development of accurate and easy to use clinical tools to measure scapula orientation. Objective: Contribute to the development of a clinical method to measure scapula orientation at 0º and 90º of shoulder elevation. Methodology: A correlational study was conducted with a sample of 20 asymptomatic subjects, selected by convenience from the student community of the ESS-IPS. Five linear measurements (M1, M2, M3, M4 and M5) were independently collected separately by 2 researchers and in 2 different moments between pre-defined bony landmarks of the vertebral column and scapula with the arm at 0º and 90º of shoulder elevation in the sagittal, coronal and scapula’s plane. Simultaneously, scapular 3D orientation was collected using an electromagnetic tracking device (Flock of Birds) and motion reconstructed according to the International Society of Biomechanics recommendations. Results and Discussion: Correlations values between linear and angular measurements of the scapular orientation, were set as acceptable and moderate whenever above a cut-point of 0.4 and 0.5, respectively. With the arm at 0º of elevation, in the coronal plane, it were found statistical significant correlations between the scapula internal rotation values and M2 and M5, and between scapula’s medial rotation and M1, M3 and M4. In the sagittal plane, it were observed statistical significant correlations between scapula’s internal rotation and M4, and the scapula’s lateral rotation, and M1 and M4. In the scapula plane, statistical significant correlations were found between the scapula’s internal rotation and M2, and scapula’s medial rotation and M1. At 90º of arm elevation, only M2 was found to be statistical significant correlated with scapula’s internal rotation. Conclusion: This preliminary results unveil a promise application of an easy to use and accurate clinical method to quantify scapula orientation based on linear measurements.

AIM Until now it is unknown to what extent malpositioning of the scapula is a relevant factor in shoulder instability that should be considered in therapy. The objective was to analyse 3D-scapular kinematics and humeral head (de-)centering in patients with atraumatic and/or traumatic shoulder instability and to investigate the correlation between the two factors. METHOD The shoulders of 28 healthy volunteers and of 14 patients each with atraumatic or traumatic instability were examined in various arm positions - with and without muscle activity - using open MR imaging. After 3D reconstruction, analyses of scapular kinematics and glenohumeral translation were performed. RESULTS In atraumatic unstable shoulders, the scapular position [30 degrees of abduction: scapulo-humeral rhythm: 3.5 +/- 2.6 : 1 vs. healthy 2.4 +/- 1.3 : 1; internal rotation: 59 +/- 9 degrees vs. healthy 49 +/- 3 degrees (p < 0.05)] and humeral head position was significantly decentered in both planes (p < 0.05). While the correlation between the two factors was high during passive elevation (r = 0.60-0.87), it was low during muscular activity (r = 0.25-0.62). In patients with traumatic instability no alterations of the scapula kinematics were observed. Significant humeral head decentering (p < 0.05) occurred only during abduction and external rotation. CONCLUSIONS Patients with atraumatic instability demonstrated significant alterations of scapular kinematics and decentering of the humeral head. In traumatic instability a decentering occurred only in specific arm positions with no changes in scapula position. Because of the high correlation between the two factors, physiotherapeutic strategies for the scapula-stabilising muscles should be adapted to the direction of instability.

Appropriate motion of the scapula is important for dynamic positioning of the glenoid during humeral elevation. A number of studies have described the typical scapular kinematics during humeral elevation in adults. However, children and adults may have differences in scapulothoracic musculature and scapular osteology. To our knowledge, no study has been performed examining scapular kinematics in children with either typical or atypical development. Consequently in children the influence of age and development on scapular motion is currently unknown. The aim of this study was to describe and compare the kinematic patterns of the scapula during humeral elevation in children with typical development and healthy adults.Fifteen adults, 7 females, 25-37 years of age, and 14 children, 8 females, 4-9 years of age, participated in this study. Kinematic data were collected using a magnetic tracking device. Subjects were asked to elevate their arm in the scapular plane (40 degrees anterior to the frontal plane) in a sequence of three trials.Significant differences were seen between the two age groups in the dependent variables. During scapular plane rotation from 25 degrees to 125 degrees , children showed greater upward rotation (43.9 degrees SD 6.39 degrees ) than adults (29.1 degrees SD 10.1 degrees ). The mean glenohumeral to scapulothoracic ratio in the scapular plane was 2.4:1 for adults, 1.3:1 for children.This study demonstrates that there are significant differences in scapular kinematic patterns between children and adults. Children have a greater contribution from the scapulothoracic joint, specifically upward rotation toward humeral elevation. From a clinical perspective, these results can be used to help determine the incorporation of stabilization and mobilization of the scapulothoracic joint during exercises for a child with impairment at the shoulder for improving shoulder function.

Measurement of scapular kinematics is an important component in the assessment of shoulder function; however, repeatability of these measurements has not been established. The purpose of this study, therefore, was to determine the repeatability of scapular rotation measures for different humeral elevation planes between trials, sessions, and days. Three-dimensional scapular rotations were collected using an electromagnetic tracking system in three planes of humeral elevation. Coefficient of multiple correlation (CMC) values were calculated between trials, sessions, and days for curves of scapular rotations. CMC values were compared with repeated measures analysis of variance (ANOVAs) and Tukey's post-hoc procedures. Tests of simple main effects were performed for significant interaction effects. Our results suggest that scapular rotation measures are repeatable between trials within the same testing session, but less repeatable between testing sessions and days. Sagittal plane elevation consistently yielded the highest CMC values for all scapular rotations. These results suggest sagittal plane elevation should be considered to evaluate differences in scapular rotations.

It is currently unknown in which ways activity of the ab- and adductor shoulder muscles affects shoulder biomechanics (scapular kinematics and glenohumeral translation), and whether these changes are relevant for alterations of the subacromial space width. The objective of this experimental in vivo study was thus to test the hypotheses that potential changes of the subacromial space width (during antagonistic muscle activity) are caused by alterations of scapular kinematics and/or glenohumeral translation. The shoulders of 12 healthy subjects were investigated with an open MRI-system at 30 degrees, 60 degrees, 90 degrees, 120 degrees and 150 degrees of arm elevation. A force of 15N was applied to the distal humerus, once causing isometric contraction of the abductors and once contraction of the adductors. The scapulo-humeral rhythm, scapular tilting and glenohumeral translation were calculated from the MR image data for both abducting and adducting muscle activity. Adducting muscle activity led to significant increase of the subacromial space width in all arm positions. The scapulo-humeral rhythm (2.2-2.5) and scapular tilting (2-4 degrees) remained relatively constant during elevation, no significant difference was found between abducting and adducting muscle activity. The position of the humerus relative to the glenoid was, however, significantly (p < 0.05) different (inferior and anterior) for adducting versus abducting muscle activity in midrange elevation (60-120 degrees). These data show that the subacromial space can be effectively widened by adducting muscle activity, by affecting the position of the humerus relative to the glenoid. This effect may be employed for conservative treatment of the impingement syndrome.

Objective Scapular motion is essential for full, functional mobility of the arm. Many shoulder pathologies are associated with alterations of scapular kinematics which have been only little studied in total shoulder arthroplasties. The aim of this study was to compare the 3D scapula kinematics in two groups of patients with total shoulder anatomic (aTSA) or reverse (rTSA) arthoplasties to asymptomatic controls of comparable age during two arm elevation tasks (abduction and flexion) and two simulations of activity of daily living (“hair combing” and “back washing”). Material/patients and methods Scapular kinematics was assessed using a Polhemus Fastrak electromagnetic device in 14 patients with aTSA (and 14 controls) and 9 patients with rTSA (and 9 controls). The 3D rotations and the 3D displacements of the barycenter of the scapula were measured at 30°, 60° and 90° of humero-thoracic (HT) elevation. Patient groups were compared with each other by Mann–Whitney U test and with their respective controls by Wilcoxon test. Results Scapulohumeral rhythm was reduced in both patient groups as compared with controls. Patients with aTSA showed more lateral rotation and more linear displacements of the scapula compared to rTSA and control groups. Nevertheless, the global kinematics pattern remained unchanged in both groups of patients. Discussion–conclusion Patients showed a greater participation of the scapula in HT elevation movements and kinematic modifications of small amplitude that could suggest a compensation mechanism for patients with aTSA. However, having a total shoulder arthroplasty does not alter the global kinematic pattern of the scapula.

Tsai N-T, McClure PW, Karduna AR. Effects of muscle fatigue on 3-dimensional scapular kinematics. Arch Phys Med Rehabil 2003;84:1000-5. Objective: To determine the effects of fatigue during an external rotation task on 3-dimensional scapular kinematics. Design: A single-group, pretest-posttest measurement de- sign. Setting: Research laboratory. Participants: Thirty healthy subjects. Interventions: Not applicable. Main Outcome Measures: Three-dimensional scapular kinematics were recorded with a Polhemus magnetic tracking device during arm elevation in the scapular plane. Results: There was a significant fatigue effect for all scap- ular rotations in the early to middle phases of humeral eleva- tion. Significantly less posterior tilting (up to 90° of elevation), external rotation (up to 120° of elevation), and upward rotation (up to 60° of elevation) were observed. Additionally, there were fair to good correlations (r range, .39 -.60) between the changes in scapular posterior tilting and the amount of muscle fatigue. Conclusions: Fatigue in shoulder external rotation altered the scapular resting position and the movement of posterior tilting in the early range during arm elevation in the scapular plane. Observed changes in scapular kinematics may affect the amount of area in the subacromial space and facilitate impinge- ment. Data regarding changes produced by fatigue of the external rotators may also help with the development of a model of diminished rotator cuff function.

Objective To quantify and compare spinal curvature and shoulder kinematics throughout the manual wheelchair (MWC) propulsion cycle for individuals with spinal cord injury (SCI) who were seated at 2 different seat dump angles. Design Single-group, repeated-measures study. Setting Academic medical center. Participants Individuals (N=28) with SCI or spinal cord disease who used MWCs completed a telephone screening, and 21 of them were eligible and completed the study. Interventions Participants' personal MWCs were modified to have seat dump angles of 0° or 14°, with a vertical backrest. Participants completed at least 3 propulsion cycles in each condition, during which spine and shoulder motion data were collected with fiberoptic and electromagnetic sensors, respectively. Main Outcome Measures Thoracolumbar spinal curvature, glenohumeral kinematics, and scapulothoracic kinematics at the start of push (SP), mid-push (MP), end of push (EP), and mid-recovery. Results Participants had significantly less lordosis in the 14° condition for all propulsion events. Median differences ranged from 2.0° to 4.6°. Lordosis differences were more pronounced in those with low SCI. Scapulothoracic internal rotation was increased in the 14° condition at SP and MP (mean differences, 2.5° and 2.7°, respectively). Relative downward rotation increased in the 14° condition at SP and MP (mean differences, 2.4° and 2.1°, respectively). Scapulothoracic differences were more pronounced in those with high SCI. No glenohumeral rotations were significantly different between the conditions. Conclusions Scapulothoracic kinematics and spinal curvature differences during propulsion may be associated with the position of other body segments or postural stability. Because no differences were observed at the glenohumeral joint, the risk of subacromial impingement may not be affected by this seat angle change.

Objectives: Though many surgeons advocate biceps tenodesis for treatment of intra-articular biceps pathology, little is known about the biomechanical effects this may have on the glenohumeral joint. The purpose of the present study is to describe in detail the effect of biceps tenodesis on shoulder muscle strength, range of motion, and scapular motion. We hypothesized that post-surgical shoulders would not show significant differences in range of motion, strength, and kinematics when compared to the uninvolved shoulder. Methods: 22 patients underwent a subpectoral biceps tenodesis and were evaluated at least 6 months following the procedure. We evaluated range of motion, strength, and scapular kinematics. Measures included glenohumeral abduction, internal and external rotation, elbow flexion and extension, internal and external rotation strength, and scapular kinematics. Subjects also completed the DASH questionnaire. Results: The average DASH score was 5.3 +/- 6.3 following surgery. The post-surgical shoulder showed a significant 8.3 degree decrease (p = 0.003) in glenohumeral abduction external rotation compared to the uninvolved shoulder. However, there were no significant differences in other measurements of glenohumeral motion or strength. Kinematic data revealed significantly increased scapular internal rotation (p = 0.02) and anterior tipping (p = 0.019) while reaching for the contralateral shoulder. Conclusion: The majority of outcome measures were equivalent when comparing the post-surgical and uninvolved shoulder function and biomechanics. Significant findings include a loss of glenohumeral abduction external rotation after surgery as well as anterior scapular tipping and rotation while reaching for the contralateral shoulder. Overall, subjects expressed minimal disability following surgery, as evidenced by their DASH scores. Nonetheless, we recommend a vigilant focus on regaining external rotation following open subpectoral biceps tenodesis in an attempt to limit or prevent loss of shoulder motion.

Background The knowledge of 3-dimensional (3D) scapular kinematics is essential for understanding the pathological lesions of shoulder and elbow in throwing athletes. To date, a number of studies about alterations of static scapular position, dynamic scapular motion, or scapular dyskinesis have been conducted, yet none of them have identified consistent pattern of altered scapular kinematics in throwing athletes. Ojective To analyze the 3D scapular kinematics of dominant and non-dominant arms in baseball players with a pathological condition of shoulder or elbow. Design Cross-Sectional Study. Setting Baseball players from middle school to professional players. Patients (or Participants) 319 baseball players who visited our clinic with the pathological condition of shoulder or elbow from December 2011 to August 2015. Interventions (or Assessment of Risk Factors) The CT scan was performed using a 64-channel multidetector CT system in a prone position with the arms at the side of the body and at 150° forward elevation with the palms toward the body. Main Outcome Measurements From 3D computed tomography, angular values of the scapula were compared between dominant and non-dominant arms with statistical analysis. Results The scapular position of dominant arms showed significantly more AT, less ST at rest and more UR, IR and less ST, PRO, AT at 150° full FE compared to the non-dominant arms. The angular increment of scapular UR, IR, PRO, and AT during arm elevation increased significantly between the paired arms. Conclusions When compared to the non-dominant arms, UR, AT and PRO with the arm at 150° FE of dominant symptomatic arms in baseball players tilted towards positive compensation while IR altered towards negative decompensation. In addition, the motion of the scapula increases significantly in dominant symptomatic arms, compared to the non-dominant arms.

Background This study set out to offer a three-dimensional description of scapular kinematics and scapulohumeral rhythm (SHR) of healthy subjects during arm elevation and lowering, as well as to compare and analyse the differences between active and passive motion of the shoulder. Methods The study examined the shoulders of ten healthy males (mean age: 23.5 years). The shoulders of the ten healthy participants were elevated and lowered while fluoroscopic images were taken, and three-dimensional bone models were created from 2D to 3D using model registration techniques. The Euler angle sequences of the models9 scapular kinematics and SHR were compared during active and passive shoulder motion. Results The scapula presented three-way movements of upward rotation, posterior tilting, and external rotation during arm elevation and lowering. During arm elevation, upward rotation showed a statistically significant difference between active and passive shoulder movements (p Conclusions In healthy subjects, scapular kinematics showed a statistically significant difference between active and passive motion during elevation in the higher range of motion, but not during lowering. In terms of upward rotation, active shoulders rotated more upward during arm elevation. There was more upward rotation in active shoulders during arm elevation. With regard to passive motion, there was more posterior tilting during arm elevation. The scapular kinematics of upward rotation and posterior tilting showed a linear rotation during arm lowering.

Scapular kinematics is difficult to measure using skin-marker-based methods due to the sliding of the scapula under the skin and muscles. Among the recent publications, an acromion marker method co...

Scapular motion is closely integrated with arm motion. Injury to a distal segment requires compensatory changes in the proximal segments leading to alterations in scapular motion. Since the effects of distal injuries on scapular kinematics remain unknown, in the present study we investigated the influences on scapular motion in patients with distal injuries.Sixteen subjects with a history of distal radius fracture and 20 asymptomatic healthy subjects (controls) participated in the study. Three-dimensional scapular and humeral kinematic data were collected on all 3 planes of shoulder elevation: frontal, sagittal, and scapular. All testing was performed in a single session; therefore, the sensors remained attached to the participants for all testing. The position and orientation data of the scapula at 30°, 60°, 90°, and 120° humerothoracic elevation and 120°, 90°, 60°, and 30° lowering were used for statistical comparisons. Independent samples t-test was used to compare the scapular internal/external rotation, upward/downward rotation, and anterior/posterior tilt between the affected side of subjects with a distal radius fracture and the dominant side of asymptomatic subjects at the same stage of humerothoracic elevation.Scapular internal rotation was significantly increased at 30° elevation (P=0.01), 90° elevation (P=0.03), and 30° lowering (P=0.03), and upward rotation was increased at 30° and 60° elevation (P0.001) on the affected side during frontal plane elevation. Scapular upward rotation and anterior tilt were significantly increased during 30° lowering on both the scapular (P=0.002 and 0.02, respectively) and sagittal planes (P=0.01 and 0.02. respectively).Patients with distal radius fractures exhibit altered scapular kinematics, which may further contribute to the development of secondary musculoskeletal pathologies.

Musculoskeletal models are intended to be used to assist in prevention and treatments of musculoskeletal disorders. To capture important aspects of shoulder dysfunction, realistic simulation of clavicular and scapular movements is crucial. The range of motion of these bones is dependent on thoracic, clavicular and scapular anatomy and therefore different for each individual. Typically, patient or subject measurements will therefore not fit on a model that uses a cadaveric morphology. Up till now, this problem was solved by adjusting measured bone rotations such that they fit on the model, but this leads to adjustments of on average 3.98° and, in some cases, even more than 8°. Two novel methods are presented that decrease this discrepancy between experimental data and simulations. For one method, the model is scaled to fit the subject, leading to a 34 % better fit compared to the existing method. In the other method, the set of possible joint rotations is increased by allowing some variation on motion constraints, resulting in a 42 % better fit. This change in kinematics also affected the kinetics: muscle forces of some important scapular stabilizing muscles, as predicted by the Delft Shoulder and Elbow Model, were altered by maximally 17 %. The effect on the glenohumeral joint contact force was however marginal (1.3 %). The methods presented in this paper might lead to more realistic shoulder simulations and can therefore be considered a step towards (clinical) application, especially for applications that involve scapular imbalance. © 2013 International Federation for Medical and Biological Engineering.

Quantitative motion analysis protocols have been developed to assess the coordination between scapula and humerus. However, the application of these protocols to test whether a subject's scapula resting position or pattern of coordination is "normal", is precluded by the unavailability of reference prediction intervals and bands, respectively. The aim of this study was to present such references for the "ISEO" protocol, by using the non-parametric Bootstrap approach and two parametric Gaussian methods (based on Student's T and Normal distributions). One hundred and eleven asymptomatic subjects were divided into three groups based on their age (18-30, 31-50, and 51-70). For each group, "monolateral" prediction bands and intervals were computed for the scapulo-humeral patterns and the scapula resting orientation, respectively. A fourth group included the 36 subjects (42 ± 13 year-old) for whom the scapulo-humeral coordination was measured bilaterally, and "differential" prediction bands and intervals were computed, which describe right-to-left side differences. Bootstrap and Gaussian methods were compared using cross-validation analyses, by evaluating the coverage probability in comparison to a 90% target. Results showed a mean coverage for Bootstrap from 86% to 90%, compared to 67-70% for parametric bands and 87-88% for parametric intervals. Bootstrap prediction bands showed a distinctive change in amplitude and mean pattern related to age, with an increase toward scapula retraction, lateral rotation and posterior tilt. In conclusion, Bootstrap ensures an optimal coverage and should be preferred over parametric methods. Moreover, the stratification of "monolateral" prediction bands and intervals by age appears relevant for the correct classification of patients.

To quantitatively evaluate the effects of commonly used shoulder exercises on shoulder kinematics and resting posture.A repeated-measures design was used with measurements performed before and after a 6-week exercise program.Twenty asymptomatic subjects with forward shoulder posture were recruited. Stretching exercises for the pectoral muscles and resisted strengthening exercises for the scapular retractors and elevators and the glenohumeral abductors and external rotators were performed three times per week for 6 weeks. A three-dimensional electromechanical digitizer was used to measure thoracic inclination and scapular orientation and position. These measurements were taken with the arm (1) at the side, (2) abducted to 90 degrees, and (3) at maximal abduction. The isometric force of glenohumeral external and internal rotation and horizontal abduction and adduction were measured with a hand-held dynamometer. All subjects were tested before and after the 6-week exercise program. Hotelling's T2 and paired t tests were used for data analysis.The strength of horizontal abduction and internal and external rotation increased after exercise (p.01). The anterior inclination of the thoracic spine decreased, and the glenohumeral contribution to arm elevation increased (p.01). Resting scapular posture did not change. As the arm was abducted to 90 degrees, the scapula showed less upward rotation and less superior translation after the exercise program (p.01).The exercise program improved muscle strength, produced a more erect upper trunk posture, increased scapular stability, and altered scapulohumeral rhythm.

Objectives: To determine the effect of thoracic posture on scapular movement patterns, active range of motion (ROM) in scapular plane abduction, and isometric scapular plane abduction muscle force. Study Design and Method: Repeated measures design. There were 34 healthy subjects (mean age, 30.2yrs). Each subject was positioned and stabilized while sitting in both erect and slouched trunk postures. In each sitting posture a three-dimensional electromechanical digitizer was used to measure thoracic flexion and scapular position and orientation in three planes. Measurements were taken with the arm (1) at the side, (2) abducted to horizontal in the scapular plane, and (3) at maximum scapular plane abduction. In each posture, isometric abduction muscle force was measured with the arm at the side and abducted to horizontal in the scapular plane. Results: In the slouched posture, the scapula was significantly more elevated in the interval between 0 to 90° abduction. In the interval between 90° and maximum abduction, the slouched posture resulted in significantly less scapular posterior tilting. There was significantly less active shoulder abduction ROM in the slouched posture (mean difference=23.6° ± 10.7°). Muscle force was not different between slouched and erect postures with the arm at the side, but with the arm horizontal muscle force was decreased 16.2% in the slouched position. Conclusion: Thoracic spine position significantly affects scapular kinematics during scapular plane abduction, and the slouched posture is associated with decreased muscle force.

Block-counterbalanced, repeated-measures crossover study.To assess scapular upward rotation positional adaptations to experimentally induced subacromial pain.Existing subacromial pathology is often related to altered scapular kinematics during humeral elevation, such as decreased upward rotation and posterior tilting. These changes have the potential to limit subacromial space and mechanically impinge subacromial structures. Yet, it is unknown whether these changes are the cause or result of injury and what the acute effects of subacromial pain on scapular upward rotation may be.Subacromial pain was induced via hypertonic saline injection in 20 participants, aged 18 to 31 years. Scapular upward rotation was measured with a digital inclinometer at rest and at 30°, 60°, 90°, and 120° of humeral elevation during a painful condition and a pain-free condition. Repeated-measures analyses of variance were conducted for scapular upward rotation position, based on condition (pain or control) and humeral position. Post hoc testing was conducted with paired t tests as appropriate.Scapular upward rotation during the pain condition was significantly increased (range of average increase, 3.5°-7.7°) compared to the control condition at all angles of humeral elevation tested.Acute subacromial pain elicited an increase in scapular upward rotation at all angles of humeral elevation tested. This adaptation to acute experimental pain may provide protective compensation to subacromial structures during humeral elevation.

Trunk rotation often accompanies humeral elevation, during daily activities as well as sports activities. Earlier studies have demonstrated that changes in spinal posture contribute to scapular motion during humeral elevation. However, the effect of trunk rotation on scapular kinematics during humeral elevation has received scant attention. This study aimed to clarify how trunk rotation affects scapular kinematics and muscle activities during humeral elevation. Electromagnetic motion capture and electromyography were used to assess scapular and clavicular motion and muscle activity in the right and left sides of 12 healthy young men. The subjects were seated and instructed to elevate both arms with the trunk in neutral, ipsilaterally rotated, or contralaterally rotated position. Ipsilaterally rotated trunk position decreased the internal rotation (by 5°, relative to neutral trunk position) and increased the upward rotation (by 4°, relative to neutral trunk position) of the scapula. Trunk position did not affect clavicular motion during humeral movement. Electromyography showed that contralaterally rotated trunk position increased the activity of the upper trapezius and serratus anterior muscles and decreased the activity of the lower trapezius. Therapists should consider the importance of trunk rotation, which may be the key to developing more efficient rehabilitation programs.