Alteration in shoulder kinematics and associated muscle activity in people with symptom of shoulder impingement
ABSTRACT 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.
- SourceAvailable from: Paula Rezende Camargo
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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. "
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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- "Research with EMG has noted late activation onset (Moraes et al., 2008), decreases in force output (Cools et al., 2005), changes in muscle balance ratios (Cools et al., 2005), and alterations in the length/tension relationship between muscle groups, all of which have an effect on rotator cuff function. Alterations in scapular kinematics associated with short pectoralis minor length have been noted by authors in patients with impingement syndrome (Endo et al., 2004; Hebert et al., 2002; Ludewig and Cook, 2000; Warner et al., 1990). Although muscle peak isometric concentric and eccentric torque has be shown to be impaired in patients with rotator cuff tendinopathy compared to asymptomatic patients (MacDermid, n.d.; Tyler et al., 2009; Warner et al., 1992), the question remains whether the alterations in muscle function arise as a result of the impingement syndrome or as a cause of impingement syndrome. "
ABSTRACT: Abstract Background Reduction of the subacromial space as a mechanism in the etiology of shoulder impingement syndromes is debated. Although a reduction in this space is associated with shoulder impingement syndromes, it is unclear if this observation is cause or consequence. Method The purposes of this descriptive review are to provide a broad perspective on the current perceptions with regard to the pathology and pathomechanics of subacromial and internal impingement syndromes, consider the role of the subacromial space in impingement syndromes, describe the intrinsic and extrinsic mechanisms considered to influence the subacromial space, and critique the level of evidence supporting these concepts. Finding Based on the current evidence, the hypothesis that a reduction in subacromial space is an extrinsic cause of impingement syndromes is not conclusively established and the evidence permits no conclusion. Interpretation If maintenance of the subacromial space is important in impingement syndromes regardless of whether it is a cause or consequence, research exploring the correlation between biomechanical factors and the subacromial space, using the later as the outcome measure, would be beneficial.Clinical Biomechanics 06/2015; DOI:10.1016/j.clinbiomech.2015.06.001 · 1.97 Impact Factor
- "Specifically, the serratus anterior stabilizes the medial border and inferior angle of the scapula, which revokes scapular anterior tilting (Ebaugh et al., 2005; McClure et al., 2001). Previous investigators have explained how the serratus anterior controls the movement of the scapula and that reduced serratus anterior activity contributes to altered scapula kinematics, such as scapular winging (Ludewig and Cook, 2000). Weakness of the serratus anterior is often related with improper scapular anterior tilting and protraction (Kuhn et al., 1995; Warner and Navarro, 1998). "