From the Department of Kinesiology, Brock University, St. Catherines, Canada (AAR, JEP, ACC, MWRH); and School of Health Professions, Franciscan Missionaries of Our Lady University, Baton Rouge, Louisiana (PP).
Am J Phys Med Rehabil. 2021 Dec 1;100(12):1176-1183. doi: 10.1097/PHM.0000000000001724.
The purpose of this study was to quantify the differences in upper limb muscle activity and kinematics when performing shoulder elastic resistance exercises with no cue, slouched posture, and corrected posture.
Fifteen healthy participants completed four shoulder elastic resistance exercises (unilateral flexion, bilateral flexion, external rotation, and external rotation with towel) across three simulated body postures (no cue, corrected posture, and slouched posture). Surface electromyography was measured on 16 upper limb muscles and kinematics were collected. Two-way repeated-measures analyses of variance examined differences in muscle activation and kinematics across postures and exercises.
Interactions between exercise and posture were found for most muscles. Muscle activity interactions existed in 14 of the 16 muscles examined, with 8 muscles having the greatest activity in the unilateral flexion, slouched condition (P < 0.0001). The slouched posture generated activity up to 88.4 ± 5.1 %MVC in the cervical extensors. Completing flexion or external rotation exercises with a slouched posture led to increased glenohumeral range of motion (P < 0.0001), but these differences were less than 5 degrees between the greatest and smallest ranges of motion (85.8 vs. 81.0 degrees).
Posture influenced muscle activation and kinematics, with slouched postures increasing muscle activity and range of motion. There was little to no difference between the no cue and corrected cue conditions, suggesting that perhaps a clinician's time may be better spent focusing on avoiding slouched postures rather than ensuring mastering technique.
本研究旨在量化在无提示、弓背姿势和矫正姿势下进行肩部弹性阻力练习时上肢肌肉活动和运动学的差异。
15 名健康参与者完成了四项肩部弹性阻力练习（单侧前屈、双侧前屈、外展和毛巾外展外旋），跨越三种模拟身体姿势（无提示、矫正姿势和弓背姿势）。表面肌电图测量了 16 块上肢肌肉的活动，运动学数据也被收集。采用双因素重复测量方差分析比较了不同姿势和练习下肌肉激活和运动学的差异。
大多数肌肉的运动和姿势之间存在交互作用。在 16 块被检查的肌肉中，有 14 块肌肉的肌肉活动存在交互作用，其中 8 块肌肉在单侧前屈、弓背姿势下的活动最大（P<0.0001）。弓背姿势使颈伸肌的活动达到最大肌力的 88.4±5.1%。在弓背姿势下完成前屈或外展练习会导致盂肱关节活动范围增加（P<0.0001），但最大和最小活动范围之间的差异小于 5 度（85.8 度和 81.0 度）。
姿势影响肌肉激活和运动学，弓背姿势增加肌肉活动和活动范围。无提示和矫正提示条件之间几乎没有差异，这表明也许临床医生的时间可以更好地用于避免弓背姿势，而不是确保掌握技术。
