The immediate effect of shoulder brace on muscle activity and scapular kinematics in subjects with shoulder impingement syndrome and rounded shoulder posture

Autor: Yuan-Chun Chiu, 邱元駿
Rok vydání: 2019
Druh dokumentu: 學位論文 ; thesis
Popis: 107
Background: Rounded shoulder posture (RSP), associated with altered scapular kinematics and imbalance of muscle activity, is one of potential risks for shoulder impingement syndrome (SIS) due to alignment deviation of scapula. Evidence showed shoulder brace improved degree of RSP by postural correction. However, it is unknown whether shoulder brace with different characteristics (tension and direction) is optimal for muscle activity and scapular kinematics in patients with SIS and RSP. Objective: The purposes of this study were to (1) compare the effect of shoulder brace (no-brace and comfortable/forced diagonal brace) on clinical RSP measurements, muscle activities and scapular kinematics in subjects with SIS and RSP; (2) compare the effect of two directions (paraspinal muscle and diagonal orientation) and two tensions (self-comfortable and forced tension) of strap on muscle activities, muscle balance ratios and scapular kinematics during arm movements in subjects with SIS and RSP. Design: Twenty-four participants with SIS and RSP were recruited and randomly assigned into 2 groups (self-comfortable following forced tension and forced following self-comfortable tension groups) with 2 directions of strap in each tension wearing shoulder brace. Each subject had the assessment 2 times with 1-week interval. Pectoralis minor index (PMI), acromial distance (AD), scapular index (SI) and shoulder angle (SA) were used to assess degree of RSP. Three-dimensional electromagnetic motion analysis and electromyography muscle activity were used to record the scapular kinematics, absolute muscle activity and muscular balance ratios during arm movements with or without shoulder brace. Main outcome measures: Scapular kinematics (upward/downward rotation, anterior/posterior tilt, external/internal rotation), absolute muscle activity (UT, MT, LT, SA) and muscle balance ratios (UT/LT, UT/SA) were main outcomes of the study. Results: All clinical measurements with the brace were significantly improved, including VAS, AD, PMI, SI, SA and FLEX-SF (p< 0.05). For muscle activities under forced tension, muscle activities were higher in diagonal brace than those in parallel brace for LT (1.2~2.3%MVIC, p< 0.05) and SA (2.3%MVIC, p= 0.015) while UT/LT muscle balance ratio were lower in diagonal brace than those in parallel brace (0.39, p= 0.019). For scapular kinematics under forced tension, upward rotation and posterior tilting of the scapula in diagonal direction were larger than those in parallel direction (1.5°, p= 0.038; 0.4°~0.5°, p< 0.05, respectively). For internal rotation under forced tension, degree of scapular kinematics in diagonal direction brace were less than those in parallel direction (1°~1.8°, p< 0.05). Conclusion: The application of shoulder brace with diagonal orientation and tension between comfortable and forced is suggested for SIS subjects with RSP.
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