Effect of Scapular Stabilizer Muscles Strength on Scapular Position.

BACKGROUND: Maintaining scapular mechanics is important for upper extremity functionality and posture. Determining the extent to which the scapular stabilizer muscles affect the scapular position may guide the creation of an exercise program for people with scapular dyskinesis. HYPOTHESIS: The serratus anterior (SA), upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) muscles play different roles on scapular position when humeral elevation increase. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 70 women aged 40 to 65 years (mean age, 49 ± 7 years) who met the inclusion criteria were included in the study. Isometric muscle strength of the SA, UT, MT, and LT was evaluated with a handheld dynamometer. For assessment of scapular position, the lateral scapular slide test (LSST) was used. Multiple stepwise regression analysis was used to evaluate scapular parameters. RESULTS: There were positive and statistically significant correlations between the isometric muscle strength of the SA, UT, MT, and LT muscles and the values at different humerus positions in the LSST (P < 0.05). The UT and SA muscles greatly affected the changes in the position of the inferior region of the scapula (R2 > 24.5%). The LT (11.3%) in neutral position, MT (25.4%) with arm abducted at 45°, and SA (34.5%) with arm abducted 90° had a major effect on the changes in the mediolateral position of the scapula. CONCLUSION: While the LT muscle affects the mediolateral position of the scapula to a large extent, the strength of the MT and SA muscles becomes effective as the shoulder elevation increases. SA and UT muscle strength have a greater effect on the position of the inferior region of the scapula. CLINICAL RELEVANCE: Dyskinesis can be observed at different levels of the scapula; therefore, it is important to determine at which level the dyskinesis is more prominent for each individual and consequently to form a personalized exercise program to increase function and control dyskinesis.

The relationship between scapular position and glenohumeral rotational range of motion in high school baseball players.

BACKGROUND: Past research indicated that scapular malposition is related to the glenohumeral internal rotation deficit (GIRD). However, there is no research examining the effect of throwing-related pain on this relationship. This study investigated the relationship between scapular position and range of motion (ROM) and compared the difference in this relationship between with and without throwing-related pain. METHODS: Forty male baseball players in high school were recruited for this study. The existence and degree of throwing-related pain were obtained from a questionnaire. Participants were divided into 2 groups according to the presence or absence of the pain. Glenohumeral internal and external rotation ROM (abduction internal rotation angle and abduction external rotation angle [ABER], respectively) were measured using a digital inclinometer. The pectoralis minor muscle length was measured using a vernier caliper and scapula index, which indicated the scapular position, measured using a measuring tape. All these measurements were taken on both dominant and nondominant sides. The GIRD and total motion arc (TMA) deficit were calculated from the ROM measurements. Groups were compared using a mixed-model analysis of variance. RESULTS: There was a significant interaction between group and ABER dominance. Other variables were not seen as the interaction effect. There was a significant positive correlation between the scapula index and TMA (r = 0.47, P = .02) and a negative correlation between the scapula index and GIRD (r = -0.65, P < .01) in the dominant side of the pain group. In addition, in the nondominant side of the pain group, the scapula index and ABER were significantly correlated (r = 0.43, P = .04). CONCLUSIONS: The results of this study indicate that the scapular position is associated with the glenohumeral ROM in high school baseball players. In addition, this study demonstrated that the scapular internally rotated position was correlated with the GIRD and TMA deficit in high school baseball players who had throwing-related pain. On the other hand, the scapular externally rotated position was correlated with increased ABER, mainly in the pain-free baseball players or on the nondominant side. These results indicated that the scapular position might affect the glenohumeral rotational ROM in high school baseball players.

Acute effects of doorway stretch on the glenohumeral rotational range of motion and scapular position in high-school baseball players.

BACKGROUND: Pectoralis minor tightness has been thought to affect the scapular position. Despite the wide implementation of doorway stretch in clinical practice owing to its apparent effectiveness in stretching the pectoralis minor, limited studies have investigated its influence on the glenohumeral rotational range of motion (ROM). This study aimed to examine the acute effects of doorway stretch on the glenohumeral rotational ROM and the correlation between the scapular position and ROM. MATERIALS AND METHODS: In total, 34 male high-school baseball players participated in this study. Outcomes included the pectoralis minor muscle length, glenohumeral rotational ROM, and scapular position. The distance between the sternocostal joint of rib 4 and the coracoid process was measured as the pectoralis minor length. Internal and external rotation ROM with the shoulder abducted at 90° were measured. The scapular position was defined by the following two measurements: the distance between the surface and the posterolateral corner of the acromion as well as the scapular index. The participants performed doorway stretch by abducting and externally rotating the shoulder at 90° and flexing the elbow at 90°. The outcomes were compared before and after stretching. Furthermore, the correlation between these changes was investigated. RESULTS: Pectoralis minor muscle length and glenohumeral internal rotation ROM was significantly higher after stretching than before, and the scapular position also significantly changed (P < .01 for both). A moderate correlation was found between the degree of change in the glenohumeral internal rotational ROM and scapular position (r = 0.44, P < .01). DISCUSSION: Our results indicated that doorway stretch significantly increased the pectoralis minor muscle length and glenohumeral internal rotation ROM and significantly altered the scapular position. Furthermore, a significant correlation between the degree of change in the scapular position and glenohumeral internal rotation ROM was observed. These results suggest that doorway stretch could be beneficial for improving the scapular position and glenohumeral internal rotation ROM, which are considered the cause of throwing injuries. Furthermore, the glenohumeral ROM may be affected by the scapular position.

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

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

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

BACKGROUND: Therapeutic exercise for scapular muscles is suggested to be effective in reducing shoulder pain in patients with rotator cuff disorders, whereas its effectiveness on scapular position and motion has remained unclear. Therefore, the aim of this systematic review was to investigate whether exercise therapy improves scapular position and motion in individuals with scapular dyskinesis. METHODS: This study is a wide systematic review including any type of clinical trial in which the effect of any type of therapeutic exercise, including scapular muscle strengthening, stretching, and scapular stabilization exercise, is investigated in adult participants. RESULTS: Twenty studies were included in this systematic review. Studies were categorized on the basis of the techniques they used to measure scapular position and motion and the included participants. Methodologic quality of the studies was assessed by the Cochrane tool of assessing the risk of bias. Eight studies used 3-dimensional techniques for measuring scapular motions. Among them, 5 studies showed significant effects of exercise on scapular motion, of which 3 studies investigated individuals with subacromial impingement syndrome (SIS). The other 12 studies used 2-dimensional measurement techniques, of which 8 studies reported significant effects of exercise on scapular position and motion both in SIS patients and in asymptomatic individuals. However, their methodologic quality was debatable. Therefore, there was conflicting evidence for the effect of exercise on scapular dyskinesis. CONCLUSION: There is a lack of evidence for beneficial effects of exercise in improving scapular position and motion in individuals with scapular dyskinesis. However, exercise is beneficial in reducing pain and disability in individuals with SIS.

Three-dimensional clavicle displacement analysis and its effect on scapular position in acute clavicle midshaft fracture.

BACKGROUND: The purpose of this study was to measure the distance of the clavicle in 3 dimensions (3D) and each direction (anterior to posterior, medial to lateral, and superior to inferior) and to analyze the correlation of the angular orientation of the scapula according to each directional distance of the clavicle. METHODS: Sixty-seven patients with Robinson 2B1 and 2B2 clavicle midshaft fracture (46.0 ± 17.4 years, men = 50, women = 17) were selected as final subjects. Patients' computed tomography was reconstructed using an image processing program (3D Slicer 4.3 software). Anteroposterior (AP) distance, medial-to-lateral distance, superior-to-inferior distance, and 3D distance of both clavicles were measured. The plane connecting the 3 points (superior pole, inferior pole, and center of glenoid) of the scapula was used to calculate differences in the angular orientation between both scapulae. RESULTS: Among each directional distance of the clavicle, only the AP distance showed negative correlation with scapular angular orientation with anterior tilting, internal rotation, and upward rotation of the scapula (Pearson's correlation coefficient: -0.68, -0.24, and -0.28; P < .001, P = .048, and P = .021). CONCLUSION: The shortening of the AP distance of the clavicle was related to the angular orientation of the scapula in acute clavicle fracture. AP shortening should be considered when determining the treatment of clavicle fracture.

Effects of scapular retraction/protraction position and scapular elevation on shoulder girdle muscle activity during glenohumeral abduction.

According to scapulohumeral rhythm, shoulder abduction is followed through scapular upward rotation to ensure joint mobility and stability. Of interest, the shoulder abduction can be performed holding the scapula in different positions and in association with scapular elevation, with possible effects on shoulder muscle activity. Therefore, the aim of the study was to analyze the activity of relevant shoulder muscles and the activity ratios between the scapulothoracic muscles, during shoulder abduction performed in different combinations of scapular position (neutral, retracted, protracted) and scapular elevation. The electromyographic activity of middle deltoid, serratus anterior, upper, middle and lower fibers of trapezius was recorded during shoulder abduction movements executed holding the scapula in neutral, retracted and protracted position, and subsequently a shoulder elevation movement. The activation of each muscle and the scapulothoracic muscles activity ratios were determined every 15 degrees, from 15° to 120° of abduction. Scapular retraction led to higher activation of the entire trapezius muscle, whereas protraction induced higher upper trapezius, middle deltoid and serratus anterior activity, along with lower activity of middle and lower trapezius. Shoulder elevation led to higher activity of the upper trapezius and middle deltoid. Moreover, it induced lower activation of the serratus anterior and middle and lower trapezius, thus leading to high ratios between the upper trapezius and the other scapulothoracic muscles, especially between 15 and 75 degrees of abduction. This study highlights that shoulder abduction performed with scapular protraction and in combination with scapular elevation leads to increased activity of the middle deltoid and upper trapezius, resulting in imbalances between the scapulothoracic muscles that could hamper the optimal scapulohumeral rhythm. The abduction performed in the aforementioned scapular conditions also induce potential reciprocal inhibition effects between the movers and stabilizers muscles of scapula, suggesting different motor control strategies of integrating a common shoulder movement with various modification of the scapular position.

The effect of scapular position on subacromial contact behavior: a cadaver study.

BACKGROUND: Patients with subacromial impingement were reported to show abnormal scapular positions during shoulder elevation. However, the relationship between the scapular positions and subacromial impingement is unclear. The purpose of this study was to biomechanically determine the effect of scapular position on subacromial contact behavior by using fresh frozen cadavers. METHODS: The peak contact pressure on the coracoacromial arch was measured with a flexible tactile force sensor in 9 fresh frozen cadaver shoulders. The measurement was performed during passive glenohumeral elevation in the scapular plane ranging from 30° to 75°. The scapular downward and internal rotations and anterior tilt were simulated by tilting the scapula in 5° increments up to 20°. The measurement was also performed with combination of scapular downward and internal rotations and anterior tilt positions. RESULTS: The peak contact pressure decreased linearly with anterior tilt, and a significant difference between neutral scapular position (1.06 ± 0.89 MPa) and anterior tilt by 20° (0.46 ± 0.18 MPa) was observed (P < .05). However, the scapular positioning in the other directions did not change the peak contact pressure significantly. Furthermore, any combination of abnormal scapular positions did not affect peak contact pressure significantly. CONCLUSION: Scapular anterior tilt decreased peak contact pressure during passive shoulder elevation. In addition, scapular downward and internal rotations had little effect on peak contact pressure. The abnormal scapular motion reported in previous studies might not be directly related to symptoms caused by subacromial impingement.

Full can test: Mechanisms of a positive test in patients with shoulder pain.

BACKGROUND: The full can test is theorized to produce compressive loads on the supraspinatus tendon within the subacromial space. Characterizing the width of the subacromial outlet, scapular orientation, and shoulder pain during the full can test will improve the mechanistic understanding of the positive full can test. METHODS: Cross-sectional repeated measures design. Participants with subacromial pain syndrome (n=30) were compared to a matched control group (n=30) during 2 conditions: passive support, and the full can test. The full can test was performed with the arm elevated to 90° in the scapular plane. In both conditions, measurements were taken of acromiohumeral distance with ultrasonography, scapular position using electromagnetic tracking, shoulder strength using a dynamometer, and shoulder pain with the 11-point rating scale. FINDINGS: During the full can test, both groups had a decreased acromial humeral distance, scapular upward rotation, posterior tilt, external rotation and clavicular protraction as compared to passive support (p<0.05). The subacromial pain group as compared to the control group reported greater shoulder pain (p<0.001), reduced strength (p=0.002) and greater scapular anterior tilt (p<0.05) during the full can test. INTERPRETATION: This study indicates the mechanisms of a full can test are a reduction in the acromial humeral distance, accompanied by scapular kinematic changes. A positive test of increased pain and reduced strength in those with subacromial pain syndrome can be explained additionally by an increase in scapular anterior tilt. These mechanistic changes may lead to tendon compression, but this cannot be verified as direct tendon compression was not measured.

Reliability, agreement, and diagnostic accuracy of the Modified Lateral Scapular Slide test.

BACKGROUND: The Lateral Scapular Slide Test is a static test used in clinical settings to assess medio-lateral inferior angle displacement and scapular asymmetry at three different degrees of shoulder abduction. However, there is no evidence in the literature about the reliability and diagnostic accuracy of a modified LSST (arm elevation in the scapular plane with loading) in a symptomatic population. OBJECTIVE: To assess the intra- and inter-rater reliability, agreement, and diagnostic accuracy of the MLSST ​ (Modified Lateral Scapular Slide Test) in subjects with and without shoulder symptoms. A new test position is examined, in which the arm is held in 90° of elevation in the scapular plane with 1 kg load. DESIGN: Within day intra- and inter-rater reliability, agreement, and diagnostic accuracy study. METHOD: Participants included 25 (42 ± 2.7 years) subjects with shoulder symptoms and 25 (40 ± 2.1 years) asymptomatic control subjects. Two raters, blinded to each other's outcomes, measured the distance between the inferior scapular angle and T7 at arms by the side, hands on hips and 90° of arm elevation in the scapular plane with 1 kg load. Measurements were performed twice, bilaterally. Intraclass correlation coefficient (ICC), minimal detectable change (MDC95%) and diagnostic accuracy were calculated. RESULTS: The ICCs for intra- and inter-rater reliability were good to high in both shoulders of symptomatic and asymptomatic groups. The MDC95% in the symptomatic group ranged between 0.67 and 1.40 cm in the symptomatic shoulder and 0.72-1.16 cm in the asymptomatic shoulder. The asymptomatic group presented a MDC95% ranging between 0.63 and 1.52 cm in the dominant and 0.60-1.41 cm in the non dominant shoulder. Positive and negative likelihood ratios ranged between 0.67-5.50 and 0.81-1.11, respectively. CONCLUSION: The MLSST had good reliability and agreement properties to assess scapular position in both groups. However, no test position had clinical utility as a diagnostic criterion for shoulder pathology.

Scapular dyskinesis after Latarjet procedure.

BACKGROUND: Because of detachment of the pectoralis minor and variation of the vector of the conjoint tendons, we hypothesized that the Latarjet procedure may alter scapular position and motion. The purpose of this study was to evaluate scapular position and motion in patients who underwent a Latarjet or a modified iliac crest bone graft transfer (ICBGT) procedure (J-bone graft). METHODS: Forty-six consecutive patients treated for recurrent anterior shoulder dislocation between 2010 and 2012 were retrospectively enrolled. Twenty-three were treated with a Latarjet and 23 with an ICBGT procedure. Twenty Latarjet and 20 ICBGT patients were available at a mean follow-up of 20 months (min, 12; max, 60). We recorded the Western Ontario Instability Index, the Rowe Score, and the Subjective Shoulder Value. Scapulothoracic position was studied according to the dyskinesis yes/no method. Intraobserver and interobserver reliability of the dyskinesis assessment was assessed. RESULTS: Intraobserver and interobserver reliability of scapula dyskinesis assessment was high (Latarjet: intratester, κ = 0.84; intertester, κ = 0.75; ICBGT: intratester, κ = 0.78; intertester, κ = 0.71). Scapular dyskinesis was observed after 5 of 20 Latarjet and after 0 of 20 ICBGT procedures (P = .047). Patients with dyskinesis had lower scores (Western Ontario Instability Index, P = .043; Rowe, P = .047; Subjective Shoulder Value, P = .046), but no statistically significant difference was found between the Latarjet and ICBGT groups. Two of the 5 scapular dyskinesis patients reached the SICK (Scapular malposition, Inferior medial scapular winging, Coracoid tenderness, and scapular dysKinesis) scapula syndrome definition. CONCLUSIONS: Scapular dyskinesis was found in 5 of 20 patients who underwent a Latarjet procedure. Dyskinesis may be related to the detachment of the pectoralis minor, and variation of the vector and the working length of the coracobrachialis and the short head of the biceps.

Effect of the dual-wall pushup plus exercise in patients with scapular dyskinesis with a winged or tipped scapula.

[Purpose] This study was performed to evaluate the clinical effect of the dual-wall pushup plus exercise in patients with scapular dyskinesis with a winged or tipped scapula. [Subject] A 32-year-old man with scapular dyskinesis participated in this study. [Methods] The subject performed the dual-wall pushup plus for 2 months, 4 days a week, for an average of 2 hours each day. The scapular dyskinesis test, linear distance of the acromion, acromion angle, and inferior scapular distance were evaluated before and after the exercise program. [Results] After 2 months of dual-wall pushup plus exercises, the scapular dyskinesis test was negative, the linear distance of the acromion decreased, the acromion angle increased, and the inferior scapular distance decreased compared with the initial measurements. [Conclusion] The dual-wall pushup plus exercise is an effective intervention in patients with scapular dyskinesis with a winged or tipped scapula.

Scapular position after the open Latarjet procedure: results of a computed tomography scan study.

BACKGROUND: The aim of this study was to investigate, through a computed tomography (CT) scan analysis, the effects of the Latarjet procedure on scapular position in an axial plane. MATERIALS AND METHODS: Twenty healthy young male subjects (mean age, 22 years; range, 18-27 years) were enrolled as a control group. Twenty young male patients (mean age, 23 years; range, 17-30 years) with recurrent anterior shoulder dislocation were enrolled as the study group. CT cuts at a proper level allowed the identification of an α angle, which defined the tilt of the scapula relative to the anterior-posterior axis. RESULTS: In the control population, the α angles on the right and left shoulders were 48° (44°-52°) and 48° (44°-54°), respectively. In the study group, the preoperative α angles at the affected and healthy shoulders were 49° (46°-52°) and 49° (44°-52°), respectively. At day 45, the corresponding angles were 45° (40°-50°) and 49° (46°-52°). At 6 months, the average α angle of the shoulder operated on was 52° (46°-58°). The α angle value was restored in 5 cases, increased in 9 cases (mean, 8°), and decreased in 6 cases (mean, 3°). CONCLUSION: A general symmetry of scapular position was observed during CT scan analysis. This balance was lost initially after the Latarjet procedure, with a decrease of the α angle and scapular protraction. Six months after surgery, a small trend toward scapular retraction was conversely observed; however, the data were not statistically significant.

Age-related, sport-specific adaptions of the shoulder girdle in elite adolescent tennis players.

CONTEXT: Tennis requires repetitive overhead movements that can lead to upper extremity injury. The scapula and the shoulder play a vital role in injury-free playing. Scapular dysfunction and glenohumeral changes in strength and range of motion (ROM) have been associated with shoulder injury in the overhead athlete. OBJECTIVE: To compare scapular position and strength and shoulder ROM and strength between Swedish elite tennis players of 3 age categories (<14, 14-16, and >16 years). DESIGN: Cross-sectional study. SETTING: Tennis training sports facilities. PATIENTS OR OTHER PARTICIPANTS: Fifty-nine adolescent Swedish elite tennis players (ages 10-20 years) selected based on their national ranking. MAIN OUTCOME MEASURE(S): We used a clinical screening protocol with a digital inclinometer and a handheld dynamometer to measure scapular upward rotation at several angles of arm elevation, isometric scapular muscle strength, glenohumeral ROM, and isometric rotator cuff strength. RESULTS: Players older than 16 years showed less scapular upward rotation on the dominant side at 90° and 180° (P < .05). Although all absolute scapular muscle strength values increased with age, there was no change in the body-weight-normalized strength of the middle (P = .9) and lower (P = .81) trapezius or serratus anterior (P = .17). Glenohumeral internal-rotation ROM and total ROM tended to decrease, but this finding was not statistically significant (P = .052 and P = .06, respectively). Whereas normalized internal-rotator strength increased from 14 to 16 years to older than 16 years (P = .009), normalized external-rotator and supraspinatus strength remained unchanged. CONCLUSIONS: Age-related changes in shoulder and scapular strength and ROM were apparent in elite adolescent tennis players. Future authors should examine the association of these adaptations with performance data and injury incidence.

Measurement properties of existing clinical assessment methods evaluating scapular positioning and function. A systematic review.

The aims were to compile a schematic overview of clinical scapular assessment methods and critically appraise the methodological quality of the involved studies. A systematic, computer-assisted literature search using Medline, CINAHL, SportDiscus and EMBASE was performed from inception to October 2013. Reference lists in articles were also screened for publications. From 50 articles, 54 method names were identified and categorized into three groups: (1) Static positioning assessment (n = 19); (2) Semi-dynamic (n = 13); and (3) Dynamic functional assessment (n = 22). Fifteen studies were excluded for evaluation due to no/few clinimetric results, leaving 35 studies for evaluation. Graded according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN checklist), the methodological quality in the reliability and validity domains was "fair" (57%) to "poor" (43%), with only one study rated as "good". The reliability domain was most often investigated. Few of the assessment methods in the included studies that had "fair" or "good" measurement property ratings demonstrated acceptable results for both reliability and validity. We found a substantially larger number of clinical scapular assessment methods than previously reported. Using the COSMIN checklist the methodological quality of the included measurement properties in the reliability and validity domains were in general "fair" to "poor". None were examined for all three domains: (1) reliability; (2) validity; and (3) responsiveness. Observational evaluation systems and assessment of scapular upward rotation seem suitably evidence-based for clinical use. Future studies should test and improve the clinimetric properties, and especially diagnostic accuracy and responsiveness, to increase utility for clinical practice.

Changes in the cervical FRR, shoulder muscle pain and position after continuous detailed assembly work.

BACKGROUND: Several risk factors for upper-extremity muscle injuries are known, including repetitive and continuous-flow assembly work. However, no study has investigated the changes in the cervical flexion-relaxation ratio (FRR) and scapular position after continuous detailed assembly work. OBJECTIVE: This study investigated the changes in the cervical FRR, trapezius muscle pain, and acromion and scapular positions after continuous detailed assembly work. METHODS: Fifteen male workers were recruited. The cervical FRR, pressure-pain threshold (PPT) of the upper and middle trapezius muscle, and acromion and scapular positions were measured in all subjects once before and once after detailed assembly work. RESULTS: The cervical FRR after detailed assembly work was significantly decreased compared with that before detailed assembly work. The PPT of the upper and middle trapezius muscle after detailed assembly work was significantly decreased compared with that before detailed assembly work. The acromion angle after detailed assembly work was significantly decreased compared with that before detailed assembly work. The scapular inferior distance after detailed assembly was significantly increased compared with that before detailed assembly work. CONCLUSIONS: Our findings suggest that detailed assembly work may cause the absence of FRR, upper trapezius and middle trapezius pain, and scapular malalignment associated with a potential risk of neck and shoulder pain.

Changes in Acromion and Scapular Position after Short-term Overhead Work.

[Purpose] This study investigated the changes in acromion and scapular position after short-term overhead work. [Subjects] Twelve males aged 20-27 years, were recruited. [Methods] We measured the acromial angle and scapular inferior distance using a palpation meter before and after overhead work. [Results] The acromion angle was significantly decreased after the overhead work compared to before. The scapular inferior distance was significantly increased after the overhead work compared to before. [Conclusion] Even though the overhead work was short-term work lasting less than one hour, it resulted in an abnormal scapular position.

Effect of the spacing of backpack shoulder straps on cervical muscle activity, acromion and scapular position, and upper trapezius pain.

[Purpose] This study investigated the effect of the spacing of backpack shoulder straps on cervical muscle activity, acromion and scapular position, and upper trapezius (UT) pain. [Subjects] Fourteen males aged 20-32 years, were recruited. [Methods] We measured the MPS (midcervical paraspinal) activity, acromial angle, scapular distance, and UT pain after gait carrying a backpack with different shoulder strap spacings. [Results] The MPS, scapular inferior distance, and UT pressure pain threshold was significantly decreased and the acromion angle was significantly increased when carrying a backpack with wide shoulder straps compared to narrow shoulder straps. [Conclusion] A backpack with wide shoulder straps may cause scapular depression syndrome and chronic UT pain.

A novel technique for determining scapulohumeral translation: a case-control and inter-rater reliability study.

BACKGROUND: Alterations in scapular and glenohumeral kinematics in patients with shoulder dysfunction have been recognized by this studies authors' and described in multiple other studies available in the literature. A reliability study was developed to assess a new technique for measuring scapulohumeral kinematics. Previous scapular position measuring techniques may require expensive equipment which decreases clinical utility. Other techniques require identification of multiple anatomic landmarks that may decrease accuracy, precision, and reliability. METHODS: A sample of asymptomatic controls and symptomatic study subjects were recruited. Each subject had markers placed on each acromion and stood at a standardized distance in front of a light. The shadow projected from the acromial marker onto a standardized, data collection board was measured during the resting, flexion, and scaption positions for bilateral shoulders. The horizontal and vertical translations of the shadows were measured compared to the resting point for both flexion and scaption. RESULTS: The scapula translated superiorly and medially during both flexion and scaption movements in all subjects and controls. There was good inter-rater reliability for measuring scapular translation with scaption (ICC= 0.81) and moderate reliability for measuring scapular translation with flexion (ICC = 0.62). There was increased superior and medial scapular translation in the subjects with flexion (p= 0.004 and p=0.002) and scaption (p= 0.01 and p=0.007) in the symptomatic shoulder compared to the asymptomatic shoulder. Superior scapular translation with flexion (p=0.0003) and scaption (p=0.006) and medial scapular translation with flexion (p<0.0001) and scaption (p<0.0001) was greater in the symptomatic subjects compared to controls. CONCLUSIONS: The scapula translates both superiorly and medially with flexion and scaption in asymptomatic and symptomatic subjects. After shoulder surgery, patients have increased superior and medial translation of the scapula compared to 1) their asymptomatic shoulder and 2) an asymptomatic control group. The current technique has good inter-rater reliability (ICC=0.81) when measuring scaption and moderate reliability when measuring flexion (ICC=0.62). LEVEL OF EVIDENCE: III Diagnostic Case-Control Study.

A comparative study on scapular static position between females with and without generalized joint hyper mobility.

BACKGROUND: Generalized joint hyper mobility predisposes some individuals to a wide variety of musculoskeletal complaints. Given the critical role of scapular position in function of shoulder, the aim of this study was to compare scapular position between persons with and without general joint hyper mobility. METHODS: By nonprobability sampling 30 hyper mobile persons at average of 22.86 ±2.77 years of age and 30 non hyper mobile persons (age 23.6 ± 2.73years) through a case-control design participated in the study. Scapular position was assessed according to the lateral scapular slide test. Independent t test and repeated measures ANOVA were used to statistically analyze scapular position differences between groups. RESULTS: Compared to non hyper mobile persons, those with General joint hyper mobility demonstrated a significantly higher superior scapula slide in dependent arm position (p = 0.03). However, no significant difference was found between another scores between two groups (p > 0.05). CONCLUSION: The results suggest that altered scapular position may be an important aspect of General joint hyper mobility.