Scapular Motion Research Articles

The comparison of biomechanics of kayak paddling between para-kayakers and elite able-bodied kayakers: a pilot study

Understanding the kinematics of the upper extremity during kayak paddling is important for both performance and injury prevention. However, there is a lack of information on scapular and shoulder kinematics in para-kayakers who have additional impairments. This study aimed to clarify the biomechanics of kayak paddling in para-kayakers. We assessed the biomechanics of 5 para-kayakers (included the subjects who competed the 2016 Rio Paralympic Games) and 10 elite able-bodied kayakers (included the subjects who competed the London Olympic Games in 2012 or world championships) during paddling on a kayak ergometer using an electromagnetic tracking device. The stroke rate, scapular motion relative to thorax, humerus motion relative to thorax, and humerus motion relative to scapula during the first 10 cycles of paddling were evaluated. During the first 10 cycles of paddling, para-kayakers showed significantly lower stroke rate compared to elite kayakers. There were also significant differences in scapular upward/downward rotation, humerothoracic plane of elevation, and grenohumeral plane of elevation between the para-kayakers and the elite kayakers. Para-kayakers who have some impairments showed lower kayak paddling performance and different movement patterns compared with elite kayakers. The results of this study could provide some information to guide training programs to improve para-kayakers’ performance.

The association of breast cancer-related lymphedema after unilateral mastectomy with shoulder girdle kinematics and upper extremity function

The purpose of this study was to examine the association of breast cancer-related lymphedema on shoulder girdle kinematics and upper extremity function. The study included 67 breast cancer survivors with and without unilateral lymphedema. Individuals were divided into non-lymphedema, moderate and severe lymphedema groups according to the volumetric measurement difference between the affected and unaffected upper extremities. A three-dimensional motion monitor-electromagnetic system was used to analyze scapular movements during the elevation and depression phases of the upper extremity elevation in the scapular plane. Shoulder range of motion was assessed with a digital inclinometer. Upper extremity function was assessed with the ‘Disabilities of the Arm, Shoulder, and Hand Questionnaire–Short Form (Quick-DASH)’. The scapular upward rotation was lower for the severe lymphedema group than for the non-lymphedema group in the 90–60–30° depression phases of arm elevation (p < .05). The scapular anterior tilt was higher for the severe lymphedema group than for the non-lymphedema group in the 30° depression phase of arm elevation (p < .05). Shoulder abduction range of motion was the lowest in the severe lymphedema group (p < .05). The non-lymphedema group had the lowest quick-DASH score and the severe lymphedema group had the highest score (p < .05). There were statistically significant moderate associations between the quick-DASH scores and scapular movements in all groups (p < .05). The development, presence and/or severity of lymphedema were associated with impaired shoulder-girdle kinematics and decreased upper extremity function. However, a need exists for longitudinal studies comparing individuals with and without lymphedema and healthy controls.

Which Risk Factors Are Associated with Pain and Patient-reported Function in Patients with a Rotator Cuff Tear?

Patient-reported measures guide physicians in clinical decision making and therefore it is critical to determine what clinical factors are associated with these scores. Psychological and physical factors are commonly studied separately in patients with rotator cuff tears to determine their influence on outcomes. It is well established that psychological distress and scapular motion change in the presence of a symptomatic rotator cuff tear. However, these factors have not been studied simultaneously in a clinical setting to determine their association with shoulder outcome scores. After controlling for relevant confounding variables, what physical and psychological factors are associated with better (1) American Shoulder and Elbow Surgeons (ASES) scores for function, (2) ASES pain scores, and (3) total ASES scores? Fifty-nine patients with a potential symptomatic rotator cuff tear were recruited and agreed to participate in this cross-sectional study. Of those, 85% (50 of 59) met eligibility criteria for a primary diagnosis of an MRI-confirmed symptomatic partial-thickness or full-thickness rotator cuff tear without a history of shoulder surgery. Demographics, rotator cuff tear size, arm flexion, and clinical scapular motion during active arm flexion were evaluated by experienced examiners using standardized procedures. Patients completed the ASES questionnaire and the Optimal Screening for Prediction of Referral and Outcomes-Yellow Flag assessment form, which measures 11 different pain-related psychological distress symptoms. Three separate stepwise multiple linear regression analyses were performed for ASES pain, function, and total scores, with significance set at p < 0.05. This model found that ASES function scores were associated with four factors: older age, increased arm flexion, increased percentage of scapular external rotation during arm flexion, and increased scores for acceptance of chronic pain (adjusted r2 = 0.67; p = 0.01). Those four factors appear to explain 67% of the observed variance in ASES function scores in patients with rotator cuff tears. Furthermore, increased percentage of scapular external rotation during arm flexion and decreased fear-avoidance beliefs related to physical activity scores (adjusted r2 = 0.36; p < 0.01) were associated with better ASES pain scores. And finally, better ASES total scores were associated with four factors: increased arm flexion, increased percentage of scapular upward rotation, increased scapular external rotation during arm flexion, and decreased fear-avoidance beliefs related to physical activity scores (adjusted r2 = 0.65; p < 0.001). Our results favor adopting a comprehensive biopsychological clinical assessment for patients with rotator cuff tears that specifically includes humeral and scapular motion, fear-avoidance behaviors, and pain coping behaviors along with demographics. These particular physical and psychological variables were found to be associated with the ASES and, therefore, should be clinically examined simultaneously and targeted as part of a tailored treatment plan. Level II, prognostic study.

Analysis of the spine posture, mobility and strength in healthy individuals with and without scapular dyskinesis

Spine posture, mobility and strength can be associated with changes in scapular movement and shoulder pain. However, these aspects have not been assessed in healthy individuals with scapular dyskinesis without shoulder and/or back pain. Objective: To analyze spine posture, mobility and strength in healthy individuals with and without scapular dyskinesis. Method: Cross-sectional study, fifty-two college-aged individuals were divided into two groups, according to scapular dyskinesis testing: a group without scapular dyskinesis (n= 19; age= 22.95±2.86 years; BMI= 22.97±3.12 kg/m²; 10 males) and another with scapular dyskinesis (n= 33; age= 22.06±2.73 years; BMI= 22.14±3.22 kg/m²; 10 males). Posture of the head and shoulders was analyzed from photographs by a postural assessment software (PAS/SAPO). Thoracic kyphosis and range of motion of the cervical and thoracolumbar spine were measured by a digital inclinometer, and the strength of the cervical and thoracolumbar spine muscles by a hand-held dynamometer. Intergroup comparison for all the variables was conducted using analysis of variance (one-way ANOVA), considering p≤0.05 as significant. Results: No intergroup difference was found for spine posture (p= 0.18-0.99), mobility (p= 0.23-0.96) and strength (p= 0.42-0.99). Conclusion: Spine posture, mobility and strength do not differ between healthy individuals with and without scapular dyskinesis. The outcomes suggest that scapular dyskinesis may be related to interpersonal variations. Future prospective studies be conducted in order to verify if these variables can change and influence the development of shoulder pain.

Three-dimensional analysis of winged scapula using four-dimensional computed tomography

It is difficult to evaluate complicated motions of winged scapula in the presence of dyskinesis. This study aimed to analyze the 3-dimensional (3D) motion of winged scapula using upright 4-dimensional computed tomography (upright 4DCT) during elevation.

Acute effect of inhibitory kinesio-tape of the upper trapezius on lower trapezius muscle excitation in healthy shoulders

IntroductionShoulder pain increases excitation of the upper trapezius (UT) and reduces excitation in the lower trapezius (LT). Despite inconclusive evidence, kinesio-tape (KT) is often used to modify muscular excitation within the UT and/or LT to help correct alterations in scapular position and motion associated with shoulder pain/injury. The objective of the current study was to determine if inhibitory KT to the UT acutely increases LT excitation and if load alters the magnitude of change in the excitation observed. MethodsTwenty-two (N = 22, 11 female) individuals with healthy shoulders (24 ± 3 years) completed 10 repetitions of an arm elevation task during 3 taping conditions (no-tape, experimental KT, sham KT) and 2 loading conditions (no load and loaded). Whole-muscle (mean grid) and spatial distribution (grid row) of LT excitation (root mean squared; RMS) was measured using a single high-density surface electromyography 32-electrode grid. Results: There was a main effect for loading condition on whole-muscle LT RMS, F (1, 19) = 38.038, p < .001, partial η2 = 0.667. Whole-muscle LT RMS was significantly higher in the loaded condition (0.055 V ±0 .005) compared to the no-load condition (0.038 V ±0 .004). No effect of tape condition was observed on whole-muscle or spatial distribution of RMS. ConclusionOur findings suggest that inhibitory KT to the UT does not alter whole-muscle excitation or shift the distribution of excitation within the LT during a repeated arm elevation task in healthy shoulders.

Relationship Between Clinical Scapular Assessment and Scapula Resting Position, Shoulder Strength, and Baseball Pitching Kinematics and Kinetics.

Background:Scapular assessment is important in examining overhead athletes, but there is inconsistency in scapular clinical assessment and its relation to pathology.Purpose:To determine the relationship between clinical scapular assessment and biomechanical scapula resting position, shoulder strength, and pitching shoulder kinematics and kinetics.Study Design:Descriptive laboratory study.Methods:Two clinicians performed scapular assessments and graded the scapula as presence or absence of scapular dyskinesis. Shoulder external rotation (ER) and internal rotation (IR) strength were collected. The 3-dimensional biomechanics of the scapula resting position (upward/downward rotation, IR/ER, and anterior/posterior tilt) were assessed while participants stood at rest, and pitching kinematics (maximum shoulder ER, shoulder abduction, shoulder horizontal abduction, shoulder rotation velocity) and kinetics (maximum shoulder distraction force) were assessed when participants pitched off the portable pitching mound that was engineered to meet major league specifications.Results:A total of 33 high school baseball pitchers (age, 16.3 ± 1.2 years; height, 184.0 ± 6.9 cm; weight, 76.8 ± 20.8 kg; hand dominance: left, 9 [27%]; right, 24 [73%]; pitch velocity, 34.7 ± 2.3 m/s) participated in this study. Of them, 15 participants had scapular dyskinesis, and 18 had normal scapulothoracic rhythm. No differences were observed for upward/downward rotation or anterior/posterior tilt, shoulder ER, shoulder abduction, or shoulder distraction force, based on the presence of scapular dyskinesis. Pitchers with scapular dyskinesis demonstrated significantly greater scapular resting IR position (effect size [ES], 0.80; 95% CI, 0.06 to 1.54; P = .020), greater nondominant shoulder ER to IR strength ratio (ES, 0.49; 95% CI, –0.02 to 1.00; P = .018), and decreased shoulder rotation velocity (ES, 14.66; 95% CI: 12.06 to 17.25; P = .016). Pitchers with greater anterior tilt demonstrated greater shoulder rotation velocity (r = –0.48; P = .006).Conclusion:Pitchers with scapular dyskinesis had greater scapular IR, greater nondominant shoulder ER to IR strength ratio, and reduced shoulder rotation velocity.Clinical Relevance:Scapular assessment may be more influenced by differential IR than upward rotation or anterior tilt. Scapular dyskinesis has no competitive performance advantage among amateur athletes. Greater understanding is needed to decipher the critical threshold between beneficial and maladaptive scapular movement patterns.

Application of Image Registration to Analyze the Clavicular Rotation of Normal Upper Limb Motion in the Sagittal Plane.

ObjectiveTo use image registration techniques to study the clavicular rotation of the shoulders in the sagittal plane.MethodsFrom 28 April 2019 to 20 May 2019, 13 healthy adults (7 males and 6 females) with no history of shoulder trauma surgery or chronic pain were recruited. Patients’ ages ranged from 22 to 42 years, with a mean age of 26.5 years. Three‐dimensional composite images of the sternum–clavicle–humerus were taken using CT images of upper limb movement in the sagittal plane in the 13 healthy adults. Four different postures were registered: (i) anatomical supine position; (ii) elbow joints lifted anteriorly in the supine position; (iii) posterosuperior hyperextension of the elbow joints in the prone position; and (iv) posteroinferior hyperextension of the elbow joints in the prone position. Image data from the humerus and clavicle in three of the postures were processed to calculate Euler angles for movements in the sagittal plane. SPSS 19 was used to perform statistical analyses.ResultsThere was no significant difference in the angles of change in the clavicle and humerus between the dominant and non‐dominant sides under different movement patterns. For upper limb movements in the sagittal plane, the clavicle displayed different Euler angles in different postures. The rotation angle from the anatomical to the horizontal position was the smallest angle, with an average value of 7.1°, whereas the rotation angle from horizontal to posterosuperior hyperextension was the largest, with an average value of 37.2°. When the upper limb moved from anterior protraction to a posterosuperior extension, the intrinsic rotation angle of the clavicle reached its maximum, with an average value of 27.9°; when moved from the anatomical to the horizontal position, 9.1% of the sagittal rotation was executed by the clavicle. During rotation from the horizontal position to posterosuperior hyperextension and from the anatomical to posterior extension, the clavicle showed relatively higher weights at 29.5% and 37.0%, respectively.ConclusionOur results showed that dominance was not a consideration when studying clavicular rotation. Image registration is an effective method that can be used to study upper limb scapular movements. Through comparing and analyzing the data, two postures had relatively large changes in the rotation angle. This can help improve indicators of clavicular rotational function during physical examinations and postoperative functional evaluations.

Scapular motion is accelerated in asymptomatic individuals with dyskinesis: An observational study

IntroductionIndividuals with shoulder and upper extremity pathology often present with altered scapular motion. Few studies have looked at variations in scapular acceleration as a way of quantifying scapular motion. The purpose was to determine the effectiveness of wireless accelerometers for detecting changes in acceleration in individuals with scapular dyskinesis. Materials/methodsTwenty-seven asymptomatic college students (mean age 24 (SD ± 1.54), 65% female, 93% right handed) were visually screened for scapular dyskinesis using previously described criteria. Of the students recruited, fifteen students were determined to have scapular dyskinesis. After securing a wireless accelerometer (MyoResearch 3D DTS) on the dominate scapula, the participants performed five repetitions of standing scaption from 0 to 140°. Linear scapular accelerations along three orthogonal axes (frontal-y, transverse-z, and sagittal-x) were collected. Intraclass correlation coefficients (ICC3, k) were used to determine the between day intra-rater reliability while a one-way analysis of variance was used to determine differences in acceleration between those with and without dyskinesis. ResultsThere was good between day intra-rater reliability for the average of all three axes (ICC = 0.79) and for the x and y axes (ICC > 0.78). Reliability was poor (ICC = 0.31) for the z-axis. There was a significant increase in overall acceleration of the scapula in those with dyskinesis (p = .039). There was also a significant increase in acceleration along the y-axis for those with dyskinesis (p = .003) but not for the other axes (p > .16). ConclusionWireless accelerometers reliably quantify scapular acceleration in healthy individuals. In a healthy population with dyskinesis, the overall magnitude of scapular acceleration was greater when compared to a healthy group without dyskinesis.

Management of Scapular Dyskinesis in Overhead Athletes

Optimal scapular function is integral to optimal shoulder function. Multiple roles of the scapula in arm function and throwing have been identified while scapular dysfunction continues to be associated with various shoulder pathologies. Although scapular motion alterations may be common in overhead athletes, various reports have shown that identification and management of the alterations can result in improved rehabilitation and performance outcomes. Considering that baseball throwing occurs as the result of integrated, multi-segmented, sequential joint motion and muscle activation within the kinetic chain, function and dysfunction within the kinetic chain needs to be understood. Furthermore, the scapula is a key component link within the chain through its function to maximize scapulohumeral rhythm and efficient throwing mechanics. Therefore, evaluation and management beginning with the scapula can produce improved outcomes related to shoulder pathology in overhead athletes. Although rehabilitation programs follow a core set of principles, they should be individualized based on the presentation of the patient and the needs for return to sport. This paper will describe scapular function in throwing, normal and abnormal scapular kinematics and muscle activations in throwing, discuss scapular dyskinesis as an impairment of function that can be associated with throwing injuries and altered performance, and how to detect impairments in order to establish proper treatment programs.

Age-related differences in humerothoracic, scapulothoracic, and glenohumeral kinematics during elevation and rotation motions

Age affects gross shoulder range of motion (ROM), but biomechanical changes over a lifetime are typically only characterized for the humerothoracic joint. Suitable age-related baselines for the scapulothoracic and glenohumeral contributions to humerothoracic motion are needed to advance understanding of shoulder injuries and pathology. Notably, biomechanical comparisons between younger or older populations may obscure detected differences in underlying shoulder motion. Herein, biplane fluoroscopy and skin-marker motion analysis quantified humerothoracic, scapulothoracic, and glenohumeral motion during 3 static poses (resting neutral, internal rotation to L4-L5, and internal rotation to maximum reach) and 2 dynamic activities (scapular plane abduction and external rotation in adduction). Orientations during static poses and rotations during active ROM were compared between subjects <35 years and >45 years of age (N = 10 subjects per group). Numerous age-related kinematic differences were measured, ranging 5–22°, where variations in scapular orientation and motion were consistently observed. These disparities are on par with or exceed mean clinically important differences and standard error of measurement of clinical ROM, which indicates that high resolution techniques and appropriately matched controls are required to avoid confounding results of studies that investigate shoulder kinematics. Understanding these dissimilarities will help clinicians manage expectations and treatment protocols where indications and prevalence between age groups tend to differ. Where possible, it is advised to select age-matched control cohorts when studying the kinematics of shoulder injury, pathology, or surgical/physical therapy interventions to ensure clinically important differences are not overlooked.

Scapular kinematics during unloaded and maximal loaded isokinetic concentric and eccentric shoulder flexion and extension movements

Characterization of scapular kinematics under demanding load conditions might aid to distinguish between physiological and clinically relevant alterations. Previous investigations focused only on submaximal external load situations. How scapular movement changes with maximal load remains unclear. Therefore, the present study aimed to evaluate 3D scapular kinematics during unloaded and maximal loaded shoulder flexion and extension. Twelve asymptomatic individuals performed shoulder flexion and extension movements under unloaded and maximal concentric and eccentric loaded isokinetic conditions. 3D scapular kinematics assessed with a motion capture system was analyzed for 20° intervals of humeral positions from 20° to 120° flexion. Repeated measures ANOVAs were used to evaluate kinematic differences between load conditions for scapular position angles, scapulohumeral rhythm and scapular motion extent. Increased scapular upward rotation was seen during shoulder flexion and extension as well as decreased posterior tilt and external rotation during eccentric and concentric arm descents of maximal loaded compared to unloaded conditions. Load effects were further seen for the scapulohumeral rhythm with greater scapular involvement at lower humeral positions and increased scapular motion extent under maximal loaded shoulder movements. With maximal load applied to the arm physiological scapular movement pattern are induced that may imply both impingement sparing and causing mechanisms.

Measurements of Tendon Movement Within the Bicipital Groove After Suprapectoral Intra-articular Biceps Tenodesis in a Cadaveric Model.

Background:Lesions of the long head of the biceps can be successfully treated with biceps tenotomy or tenodesis when surgical management is elected. The advantage of a tenodesis is that it prevents the potential development of a cosmetic deformity or cramping muscle pain. Proponents of a subpectoral tenodesis believe that “groove pain” may remain a problem after suprapectoral tenodesis as a result of persistent motion of the tendon within the bicipital groove.Purpose/Hypothesis:To evaluate the motion of the biceps tendon within the bicipital groove before and after a suprapectoral intra-articular tenodesis. The hypothesis was that there would be minimal to no motion of the biceps tendon within the bicipital groove after tenodesis.Study Design:Controlled laboratory study.Methods:Six fresh-frozen cadaveric arms were dissected to expose the long head of the biceps tendon as well as the bicipital groove. Inclinometers and fiducials (optical markers) were used to measure the motions of the scapula, forearm, and biceps tendon through a full range of shoulder and elbow motions. A suprapectoral biceps tenodesis was then performed, and the motions were repeated. The motion of the biceps tendon was quantified as a function of scapular or forearm motion in each plane, both before and after the tenodesis.Results:There was minimal motion of the native biceps tendon during elbow flexion and extension but significant motion during all planes of scapular motion before tenodesis, with the most motion occurring during shoulder flexion-extension (20.73 ± 8.21 mm). The motion of the biceps tendon after tenodesis was significantly reduced during every plane of scapular motion compared with the native state (P < .01 in all planes of motion), with a maximum motion of only 1.57 mm.Conclusion:There was a statistically significant reduction in motion of the biceps tendon in all planes of scapular motion after the intra-articular biceps tenodesis. The motion of the biceps tendon within the bicipital groove was essentially eliminated after the suprapectoral biceps tenodesis.Clinical Relevance:This arthroscopic suprapectoral tenodesis technique can significantly reduce motion of the biceps tendon within the groove in this cadaveric study, possibly reducing the likelihood of groove pain in the clinical setting.

Effects of Conscious Control of Scapular Orientation in Oral Cancer Survivors With Scapular Dyskinesis: A Randomized Controlled Trial.

Objectives:Spinal accessory nerve dysfunction is one of the complications of neck dissection in patients with oral cancer. This study aimed to explore the effects of long-term scapular-focused exercises and conscious control of scapular orientation on scapular movement and quality of life (QoL).Methods:This study was a randomized controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Thirty-six patients with oral cancer were randomly allocated to the motor-control group (scapular-focused exercise + conscious control of scapular orientation) or the regular-exercise group (scapular-focused exercises only). Both groups received conventional physical therapy after neck dissection for 3 months. Shoulder pain intensity, active range of motion (AROM) of shoulder abduction, scapular muscle strength and activity under maximal voluntary isometric contraction (MVIC), scapular muscle activity when performing scapular movements, and QoL were measured at baseline, 1 month after the start of the intervention, and the end of the intervention.Results:Both groups showed significant improvement in all outcomes except shoulder pain intensity. After the 3-month intervention, the motor-control group had more significant improvement in AROM of shoulder abduction with a 19° difference (95% CI: 10-29, P < .001), muscle strength of upper trapezius with an 11 N difference (95% CI: 2-20; P = .021), and QoL than the regular-exercise group. When performing shoulder horizontal adduction and flexion, the relative value (%MVIC) of serratus anterior was smaller in the motor-control group with a 106%MVIC difference (95% CI: 7-205, P = .037).Conclusions:Scapular-focused exercises have promising effects on spinal accessory nerve dysfunction. Combining scapular-focused exercises with conscious control of scapular orientation has more remarkable benefits on AROM of shoulder abduction, UT muscle strength, and muscle activation pattern than the scapular-focused exercises alone. Conscious control of scapular orientation should be considered to integrate into scapular-focused exercises in patients with oral cancer and scapular dyskinesis.Trial registry name and URL, and registration number: ClinicalTrials.gov (URL: https://clinicaltrials.gov; Approval No: NCT03545100)

Effect of Trunk Anterior Tilt Restriction on Scapula Movement and Finger Vertebral Distance during Shoulder Internal Rotation of Hand-behind-back Movement

Effect of Trunk Anterior Tilt Restriction on Scapula Movement and Finger Vertebral Distance during Shoulder Internal Rotation of Hand-behind-back Movement

Influence of Pre-Emptive Scapular Posterior Tilt on Scapular Muscle Activation and Scapulohumeral Movements during Shoulder Horizontal Abduction in the Prone Position

Influence of Pre-Emptive Scapular Posterior Tilt on Scapular Muscle Activation and Scapulohumeral Movements during Shoulder Horizontal Abduction in the Prone Position

Differences in Scapular Movement and Muscle Activity of the Periscapular Muscle According to the Belt-tying Movement Method

Differences in Scapular Movement and Muscle Activity of the Periscapular Muscle According to the Belt-tying Movement Method

Differences in scapular motion and parascapular muscle activities among patients with symptomatic and asymptomatic rotator cuff tears, and healthy individuals.

BackgroundAltered scapular motion is thought to be one of the factors associated with the development of symptomatic rotator cuff tears. However, the differences in kinematics and muscle activities of scapular upward/downward rotation between patients with symptomatic and asymptomatic tears are unclear. The purpose of this study was to compare the differences in kinematics and muscle activities of scapular rotation among patients with symptomatic and asymptomatic tears, and healthy individuals.MethodsTwenty-three patients with rotator cuff tears and 9 healthy individuals (healthy group) participated in this study. Based on a visual analog scale (VAS, 0-100 mm), the patients were divided into symptomatic (13 patients; VAS ≥20 mm) and asymptomatic (10 patients; VAS <20 mm) groups. Scapular upward rotation was measured with a digital inclinometer. Elasticities of the upper trapezius, levator scapulae, and rhomboid major were assessed by using ultrasound real-time tissue elastography to quantify their muscle activities. All measurements were performed at 0°, 60°, 90°, and 120° of active arm elevation in the scapular plane.ResultsScapular upward rotation was significantly less in the symptomatic group (9.4° ± 5.6°) compared with the asymptomatic group (15.7° ± 6.0°; P = .022) at 90° of arm elevation. The activity of the levator scapulae was significantly higher in the symptomatic group compared with the asymptomatic and healthy groups (P = .013 and P = .005, respectively) at 90° of arm elevation. The activity of the upper trapezius was significantly higher in the symptomatic group compared with the healthy group (P = .015) at 120° of arm elevation.ConclusionPatients with symptomatic rotator cuff tears showed less scapular upward rotation and higher activity of the levator scapulae at 90° of arm elevation compared to patients with asymptomatic rotator cuff tears.

Kinetic Chain Exercise Intervention Improved Spiking Consistency and Kinematics in Volleyball Players With Scapular Dyskinesis.

Chang, C-C, Chang, C-M, and Shih, Y-F. Kinetic chain exercise intervention improved spiking consistency and kinematics in volleyball players with Scapular Dyskinesis. J Strength Cond Res 36(10): 2844-2852, 2022-Scapular dyskinesis (SD) is a common problem among volleyball players with chronic shoulder pain. This randomized controlled study examined the effectiveness of kinetic chain (KC) training on neuromuscular performance of the scapula and trunk during volleyball spikes. Forty volleyball players with SD and chronic shoulder pain received 4 weeks of KC training or the conventional shoulder exercise training (CT). Shoulder pain was assessed using the visual analogue scale (VAS) every week. The kinematics and muscle activation of the shoulder and upper trunk, and proprioceptive feedback magnitude (PFM) for scapular movement consistency, were recorded at the maximum shoulder flexion (T1) and ball contact (T2) during spiking tasks. The two-way repeated measures analysis of variances was used to assess the between-group differences before and after the intervention. The results showed a significant time by group interaction for the upper trunk rotation ( p < 0.001) and PFM ( p = 0.03) at T2. The post-hoc test indicated that the KC group significantly increased contralateral rotation of the upper trunk (9.63 ± 4.19° vs. -4.25 ± 10.05°), and improved movement consistency (error: 8.88 ± 11.52° vs. 19.73 ± 12.79°) at T2 compared with the CT group. Significant time effects were also identified for VAS, scapular upward rotation (T1 and T2), upper trunk contralateral side-bending and PFM at T1, and upper trunk contralateral rotation at T2. In conclusion, both KC and CT training would relieve shoulder pain and improve scapular and trunk movement, whereas the KC program was more effective for increasing scapular movement consistency and upper trunk rotation during volleyball spikes.

Influence of Pre-Emptive Scapular Posterior Tilt on Scapular Muscle Activation and Scapulohumeral Movements during Shoulder Horizontal Abduction in the Prone Position

Influence of Pre-Emptive Scapular Posterior Tilt on Scapular Muscle Activation and Scapulohumeral Movements during Shoulder Horizontal Abduction in the Prone Position