Kiba Hospital, Medical Corporation, Juzankai, Osaka, Japan.
Graduate School of Health Sciences, Graduate School of Kansai University of Health Sciences, Osaka, Japan.
J Back Musculoskelet Rehabil. 2024;37(4):967-974. doi: 10.3233/BMR-230217.
The normal value of the scapular muscle activity ratio during arm elevation is not clear.
To obtain normal values of the scapular muscle activity ratio during arm elevation in healthy individuals.
This cross-sectional study enrolled 47 healthy people. The participants performed shoulder flexion and lowered task with 90-degree movements every 2 seconds. Muscle activities of scapular muscles were measured. For normalization, the maximum isometric contraction of the shoulder flexion was measured at 90∘ (reference contraction). The integrated electromyographic value (IEMG) obtained during the task was normalized by IEMG during the reference contraction and the relative IEMG value was calculated. Then, the scapular muscle activity ratio was computed. The relationship between muscle strength and other factors was also investigated.
The median values for upper trapezius/serratus anterior and upper trapezius/lower trapezius were often approximately 1, and that for upper trapezius/middle trapezius was often between 1 and 2. The shoulder flexion isometric strength and scapular muscle activity ratio showed significant negative correlations in multiple phases.
Normal values for upper trapezius/serratus anterior and upper trapezius/lower trapezius during arm elevation and lowering were generally 1. Low muscle strength may contribute to an abnormal scapular muscle activity balance.
手臂抬高时肩胛带肌活动比率的正常值尚不清楚。
获得健康个体手臂抬高时肩胛带肌活动比率的正常值。
本横断面研究纳入了 47 名健康人。参与者以每 2 秒 90°的运动进行肩部前屈和降低任务。测量肩胛带肌肉的肌肉活动。为了进行归一化，在 90°（参考收缩）处测量肩前屈的最大等长收缩。将任务期间获得的积分肌电值（IEMG）通过参考收缩期间的 IEMG 进行归一化，并计算相对 IEMG 值。然后计算肩胛带肌活动比率。还研究了肌肉力量与其他因素之间的关系。
在多个阶段，三角肌上部/前锯肌和三角肌上部/下部的中位数通常接近 1，三角肌上部/中部的中位数通常在 1 到 2 之间。等长握力和肩胛带肌活动比率在多个阶段均呈显著负相关。
手臂抬高和降低时三角肌上部/前锯肌和三角肌上部/下部的正常值通常为 1。肌肉力量低可能导致肩胛带肌活动平衡异常。
