ELECTROMYOGRAPHIC ACTIVITY OF THE ABDOMINAL AND LOW-BACK MUSCULATURE DURING THE GENERATION OF ISOMETRIC AND DYNAMIC AXIAL TRUNK TORQUE - IMPLICATIONS FOR LUMBAR MECHANICS
ELECTROMYOGRAPHIC ACTIVITY OF THE ABDOMINAL AND LOW-BACK MUSCULATURE DURING THE GENERATION OF ISOMETRIC AND DYNAMIC AXIAL TRUNK TORQUE - IMPLICATIONS FOR LUMBAR MECHANICS
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DOI：
10.1002/jor.1100090112
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发表时间：
1991-01-01
影响因子：
2.8
通讯作者：
MCGILL, SM
中科院分区：
文献类型：
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作者：
MCGILL, SM
这项研究的重点是躯干肌肉组织的肌电活动，因为职业性扭转与腰痛发生率增加之间的联系已得到充分证明。 10 名男性和 15 名女性自愿参加了这项研究，其中检查了肌肉活动的几个方面。 第一个方面评估等长运动期间的肌电关系。 肌肉之间和受试者之间的这种关系存在很大差异。 此外，尽管尽最大努力产生轴向扭矩（例如，腹直肌，最大随意收缩；22% 外斜肌，52%；内斜肌，55%；背阔肌，74%；上竖脊肌 [T9]，61%；下竖脊肌，从非扭转活动获得的肌电活动水平（标准化）到最大电活动）并不是最大。 ]L3[，33%）。 在该研究的第二个方面，在以 30 度/秒和 60 度/秒的速度进行的动态轴向扭转试验中检查了肌肉活动。 背阔肌和外斜肌似乎在整个扭转范围内强烈参与轴向扭矩的产生，并且上竖脊肌的活动显示出与轴向扭矩和扭转方向的紧密联系，尽管它们没有贡献轴向扭矩的机械潜力，这表明它们具有稳定作用。 该研究的第三个方面是建立一个模型，该模型由三维骨盆、胸腔和腰椎组成，并由轴向扭转和肌肉肌电图的运动学测量驱动。 最大扭转力过程中标准化肌电活动水平相对较低，加上激动剂-拮抗剂共同收缩水平较高，导致模型严重低估了测量的扭矩（例如，测量的 91 Nm 预测为 14 Nm）。 这种主导的协同性表明，扭转过程中关节的稳定性对于腰椎来说比产生大水平的轴向扭矩重要得多。
This study focused on the electromyographic activity of the trunk musculature, given the well-documented link between occupational twisting and the increased incidence of low back pain. Ten men and 15 women volunteered for this study, in which several aspects of muscle activity were examined. The first aspect assessed the myoelectric relationships during isometric exertions. There was great variability in this relationship between muscles and between subjects. Further, the myoelectric activity levels (normalized) to maximal electrical activity) obtained from nontwist activities were not maximal despite maximal efforts to generate axial torque (e.g., rectus abdominis, maximum voluntary contraction; 22% external oblique, 52%; internal oblique, 55%; latissimus dorsi, 74%; upper erector spinae [T9], 61%; lower erector spinae ]L3[, 33%). In the second aspect of the study, muscle activity was examined during dynamic axial twist trials conducted at a velocity of 30 and 60-degrees/s. The latissimus dorsi and external oblique appeared to be strongly involved in the generation of axial torque throughout the twist range and activity in the upper erector spinae displayed a strong link with axial torque and direction of twist, even though they have no mechanical potential to contribute axial torque, suggesting a stabilization role. The third aspect of the study was comprised of the formulation of a model consisting of a three-dimensional pelvis, rib cage, and lumbar vertebrae and driven from kinematic measures of axial twist and muscle electromyograms. The relatively low levels of normalized myoelectric activity during maximal twisting efforts coupled with large levels of agonist-antagonist cocontraction caused the model to severely underpredict measured torques (e.g., 14 Nm predicted for 91 Nm measured). Such dominant coactivity suggests that stabilization of the joints during twisting is far more important to the lumbar spine than production of large levels of axial torque.