Gaffney Brecca M, Maluf Katrina S, Curran-Everett Douglas, Davidson Bradley S
Department of Mechanical and Materials Engineering, University of Denver, United States.
Department of Physical Medicine and Rehabilitation, Physical Therapy and Rehabilitation Science Programs, University of Colorado Anschutz Medical Campus, United States.
J Electromyogr Kinesiol. 2014 Aug;24(4):542-9. doi: 10.1016/j.jelekin.2014.04.008. Epub 2014 Apr 28.
The first aim of this investigation was to quantify the distribution of trapezius muscle activity with different scapular postures while seated. The second aim of this investigation was to examine the association between changes in cervical and scapular posture when attempting to recruit different subdivisions of the trapezius muscle. Cervical posture, scapular posture, and trapezius muscle activity were recorded from 20 healthy participants during three directed shoulder postures. Planar angles formed by reflective markers placed on the acromion process, C7, and tragus were used to quantify cervical and scapular posture. Distribution of trapezius muscle activity was recorded using two high-density surface electromyography (HDsEMG) electrodes positioned over the upper, middle, and lower trapezius. Results validated the assumption that directed scapular postures preferentially activate different subdivisions of the trapezius muscle. In particular, scapular depression was associated with a more inferior location of trapezius muscle activity (r=0.53). Scapular elevation was coupled with scapular abduction (r=0.52). Scapular adduction was coupled with cervical extension (r=0.35); all other changes in cervical posture were independent of changes in scapular posture. This investigation provides empirical support for reductions in static loading of the upper trapezius and improvements in neck posture through verbal cueing of scapular posture.
本研究的首要目的是量化坐位时不同肩胛骨姿势下斜方肌活动的分布情况。本研究的第二个目的是检验在试图募集斜方肌不同亚部时颈椎和肩胛骨姿势变化之间的关联。在三种特定的肩部姿势下，记录了20名健康参与者的颈椎姿势、肩胛骨姿势和斜方肌活动。通过放置在肩峰、C7和耳屏上的反光标记形成的平面角度来量化颈椎和肩胛骨姿势。使用两个高密度表面肌电图（HDsEMG）电极记录斜方肌活动的分布，电极分别置于斜方肌的上、中、下部分。结果验证了特定肩胛骨姿势优先激活斜方肌不同亚部的假设。特别是，肩胛骨下沉与斜方肌活动位置更靠下有关（r = 0.53）。肩胛骨上提与肩胛骨外展相关（r = 0.52）。肩胛骨内收与颈椎伸展相关（r = 0.35）；颈椎姿势的所有其他变化与肩胛骨姿势的变化无关。本研究为通过对肩胛骨姿势的言语提示来减少上斜方肌的静态负荷和改善颈部姿势提供了实证支持。
