Alterations in Shoulder Kinematics and Associated Activity in People with Symptoms of Shoulder Impingement

Program in Physical Therapy, Department of Physical Medicine and Rehabilitation, Box 388 Mayo, 420 Delaware St, University of Minnesota, Minneapolis, MN 55455, USA. .
Physical Therapy (Impact Factor: 2.53). 04/2000; 80(3):276-91.
Source: PubMed


Treatment of patients with impingement symptoms commonly includes exercises intended to restore "normal" movement patterns. Evidence that indicates the existence of abnormal patterns in people with shoulder pain is limited. The purpose of this investigation was to analyze glenohumeral and scapulothoracic kinematics and associated scapulothoracic muscle activity in a group of subjects with symptoms of shoulder impingement relative to a group of subjects without symptoms of shoulder impingement matched for occupational exposure to overhead work.
Fifty-two subjects were recruited from a population of construction workers with routine exposure to overhead work.
Surface electromyographic data were collected from the upper and lower parts of the trapezius muscle and from the serratus anterior muscle. Electromagnetic sensors simultaneously tracked 3-dimensional motion of the trunk, scapula, and humerus during humeral elevation in the scapular plane in 3 handheld load conditions: (1) no load, (2) 2. 3-kg load, and (3) 4.6-kg load. An analysis of variance model was used to test for group and load effects for 3 phases of motion (31(-60(, 61(-90(, and 91(-120().
Relative to the group without impingement, the group with impingement showed decreased scapular upward rotation at the end of the first of the 3 phases of interest, increased anterior tipping at the end of the third phase of interest, and increased scapular medial rotation under the load conditions. At the same time, upper and lower trapezius muscle electromyographic activity increased in the group with impingement as compared with the group without impingement in the final 2 phases, although the upper trapezius muscle changes were apparent only during the 4.6-kg load condition. The serratus anterior muscle demonstrated decreased activity in the group with impingement across all loads and phases.
Scapular tipping (rotation about a medial to lateral axis) and serratus anterior muscle function are important to consider in the rehabilitation of patients with symptoms of shoulder impingement related to occupational exposure to overhead work. [Ludewig PM, Cook TM. Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement.

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    • "Muscle activity in three axioscapular muscles essential for arm elevation (Paine and Voight 2013; Veiersted 1991) was recorded by electromyography (EMG) using surface electrodes , simultaneously with recording the movements of the arm and of the thoracic curvature by using the Zebris ® equipment. The EMG surface electrodes were applied on the upper trapezius (UT), the lower trapezius (LT) and the serratus anterior (SA) muscles on the right side of the body (Ludewig and Cook 2000; Veiersted 1991) (Fig. 1d). The electrodes were placed along the muscle fibers and the inter-electrode center-to-center distance was approximately 20 mm. "
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    ABSTRACT: Purpose: Long-term use of unfavorable postures, congenital deformations and degenerative processes associated with aging or disease may generate an increased thoracic curvature resulting in pain and disability. We wanted to examine whether a slouched postural alignment with increased thoracic kyphosis changes the shoulder kinematics and muscle activity in upper trapezius (UT), lower trapezius (LT) and serratus anterior (SA) during arm elevation. The aim was to determine if a slouched posture influences range of motion, muscle activation patterns, maximal muscle activity and the total muscle work required when performing arm elevations. Method: Twelve male subjects (23.3 ± 1.5 years) performed maximum arm elevations in upright and slouched postures. A combined 3D movement and EMG system recorded arm movements and spine curvature simultaneously with EMG activity in the UT, LT and SA. Results: Slouched posture affected the biomechanical conditions by significantly decreasing maximum arm elevation by ~15° (p < 0.001) and decreasing arm movement velocity by ~8 % during movements upwards (p < 0.001) and downwards (p = 0.034). The peak muscle activity increased in all muscles: UT (p = 0.034, +32.3 %), LT (p = 0.001, +48.6 %) and SA (p = 0.007, +20.9 %). The total muscle work increased significantly in the slouched posture during movements upwards: UT (p = 0.003, +36.6 %), LT (p < 0.001, +89.0 %), SA (p = 0.002, +19.4 %) and downwards: UT (p = 0.012, +29.8 %) and LT (p < 0.001, +122.5 %). Conclusion: An increased thoracic kyphosis was found associated with marked increased physical costs when performing arm movements. Hence, patients suffering from neck-shoulder pain and disability should be investigated and treated for defective thoracic curvature issues.
    Arbeitsphysiologie 10/2015; DOI:10.1007/s00421-015-3257-y · 2.19 Impact Factor
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    • "According to our results, the normalized RMS value of the UT at 40% MVC force corresponded to approximately 39% MVC RMS. In several previous studies, the maximum EMG activities of the UT during shoulder elevation in healthy subjects were less than 30% MVC (Ebaugh et al., 2005; Lin et al., 2005; Ludewig and Cook, 2000). In addition, Kelly et al. (2005) reported that the EMG activities of the UT during shoulder elevation tasks in patients with symptomatic and asymptomatic rotator cuff tears were 39% and 20% MVC, respectively. "
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    ABSTRACT: The purpose of this study was to clarify whether the activity of the shoulder girdle muscles could be estimated by measuring the elasticity of these muscles under several levels of muscle contraction through ultrasound real-time tissue elastography (RTE). Ten healthy men performed submaximal voluntary contractions (MVC) in each manual muscle testing position for the middle deltoid, upper trapezius, supraspinatus, levator scapulae, and rhomboid major. The elasticity of these muscles was measured using ultrasound RTE during the task. The strain ratio of the muscle to an acoustic coupler was calculated as an assessment index of the muscle elasticity. Higher strain ratio values imply lower elasticity. In addition, the electromyographic activity was recorded from surface electrodes attached only to the middle deltoid and upper trapezius. The strain ratios were negatively correlated with the normalized root mean square values for the middle deltoid (r=-0.659, p<0.001) and upper trapezius (r=-0.554, p<0.001). The strain ratios of all the muscles decreased with an increase from 10% MVC force to 30% MVC force. Ultrasound RTE may be useful for noninvasively assessing the activity of the shoulder girdle muscles at certain shoulder positions with low levels of muscle contraction. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Journal of Electromyography and Kinesiology 07/2015; 25(5). DOI:10.1016/j.jelekin.2015.07.010 · 1.65 Impact Factor
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    • "The etiology of SAPS is not yet understood, but there is evidence showing inflammation and degeneration of the bursa and rotator cuff tendons on the sub-acromial space (Lewis, 2011; Diercks et al., 2014). Furthermore, alterations in kinematics (Ludewig and Cook, 2000; Timmons et al., 2012), muscle activity/performance (Camargo et al., 2008; Phadke et al., 2009) and the presence of active trigger points (TrPs) (Hidalgo-Lozano et al., 2010; Alburquerque-Sendín et al., 2013) have also been reported. "
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    ABSTRACT: Topographical pain maps (TPM) are useful tools to assess deep tissue sensitivity in musculoskeletal pain conditions. There is evidence suggesting bilateral sensitivity in subacromial pain syndrome (SAPS), although it is not widely accepted. No previous study has investigated TPM of the shoulder in SAPS. To investigate whether differences for TPM of the shoulder are evident among patients with unilateral SAPS and controls. Pressure pain thresholds (PPTs) were assessed 3 times at each point and there was a 20 s rest period between each one. The TPM were calculated using 29 pre-determined points on both shoulders in all groups by inverse distance weighted interpolation of PPT data. Multivariate Analysis of Covariance was applied to detect differences in PPTs between groups, sides, points (gender as covariate). The results revealed significant differences between points and genders (both, P < 0.001), but not between groups (P = 0.243) and sides (P = 0.812). Heterogeneous distribution of mechanical pain sensitivity was found in both groups as the PPTs were lower on the root spine of the scapula and the posterior border of the acromion (points 5-8, P < 0.05), glenohumeral joint (points 17-20, P < 0.01) and the anterior deltoid muscle (points 21-25, P < 0.001) compared to the average of the other sites on the shoulder. Women exhibited bilateral lower PPTs in all points than men in both groups (all, P < 0.01). This study revealed no differences for mechanical pain sensitivity in patients with SAPS experiencing lower levels of pain compared with matched controls, but showed heterogeneous distribution of PPTs in the shoulder. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Manual therapy 07/2015; DOI:10.1016/j.math.2015.07.002 · 1.71 Impact Factor
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