Siu Aaron, Schinkel-Ivy Alison, Drake Janessa Dm
School of Kinesiology & Health Science, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
School of Kinesiology & Health Science, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
Hum Mov Sci. 2016 Oct;49:267-76. doi: 10.1016/j.humov.2016.07.010. Epub 2016 Aug 11.
To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.
为了解躯干肌肉组织的激活模式，考虑相邻结构（如上肢）以及作用于移动手臂的肌肉的影响也很重要。本研究调查了手臂位置对躯干肌肉组织以及在躯干运动范围（最大躯干轴向扭转、屈曲和侧弯）期间移动手臂的肌肉的激活模式和共同激活的影响。15名男性和15名女性，无下背痛症状，进行最大躯干运动范围的动作，轴向扭转有三种手臂位置（放松、交叉、外展），屈曲和侧弯有两种位置（放松、交叉）。双侧采集了八块肌肉的肌电图数据，并对躯干肌肉和移动手臂的肌肉（上斜方肌、背阔肌）之间的激活信号进行了交叉相关分析。结果显示，在最大躯干轴向扭转期间，外展手臂位置时，躯干肌肉和上斜方肌之间的肌肉共同激活（交叉相关系数更高）始终更大，而背阔肌与躯干的配对结果更依赖于特定的躯干肌肉（腹部或背部）和背阔肌（右侧或左侧），以及运动范围。本研究结果有助于理解上肢与躯干之间的相互作用，并突出手臂位置对躯干肌肉组织的影响。此外，将本研究结果与背部或肩部有问题的个体的结果进行比较，最终可能有助于阐明这些问题的潜在机制或促成因素。
