Research Center, Montreal Rehabilitation Institute, Montreal, Quebec, Canada; School of Rehabilitation, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.
J Electromyogr Kinesiol. 1992;2(2):91-102. doi: 10.1016/1050-6411(92)90020-J.
This article reports the results of a comparative study on directional patterns of muscle activation at the lower limb in 15 subjects with hemiparesis and 18 healthy subjects. Subjects were required to exert static hip and knee torques using multidirectional and biarticular dynamometers designed for the lower limbs. Hip torques were performed in abduction, adduction, flexion, extension, and in combined directions (e.g., hip flexion and abduction) and knee torques were exerted in flexion and extension. The required torque levels corresponded to approximately 5% of the maximal voluntary contraction of healthy subjects. Electromyographic (EMG) activities of the rectus femoris, biceps femoris, gracilis, gluteus medius, gluteus maximus, vastus lateralis, tibialis anterior, and soleus were recorded during these torques. The descriptive analysis involved comparison between either the polar plots (for hip tasks) or the histograms (for knee tasks) representing the mean muscle activity obtained across subjects during torques exerted in each direction for the three groups of muscles analyzed (normal, paretic, and nonparetic muscles). Ciucular statistics were also used to characterize directional patterns of activation in each muscle during hip tasks while linear statistics permitted one to analyze these patterns during knee tasks. In general, the results of both the descriptive and inferential statistical analyses indicated that directional patterns of muscle activation during hip and knee torques are not altered in subjects with hemiparesis. These results are in contrast to the disturbances observed previously in a study of directional patterns of muscle activation at the upper extremity in this population. It is suggested that the contrast between the present results and those obtained at the upper limb in subjects with hemiparesis may reflect the difference in the motor recovery of upper and lower paretic limbs or in the severity of spasticity in the muscles involved at the studied joints. Results of this study also showed that the paretic muscles often demonstrate larger EMG signals than normal and nonparetic muscles, especially during knee flexion torques. These last observations, in addition to the fact that some subjects with hemiparesis could not complete all of the tasks with their paretic limb, under-score the muscle weakness inherent to this population.
本文报告了一项对比研究的结果，研究了 15 名偏瘫患者和 18 名健康受试者下肢肌肉激活的方向模式。要求受试者使用为下肢设计的多向和双关节测力计，施加静态髋关节和膝关节扭矩。髋关节扭矩在外展、内收、屈曲、伸展以及组合方向（例如髋关节屈曲和外展）下进行，膝关节扭矩在屈曲和伸展下进行。所需的扭矩水平约为健康受试者最大随意收缩的 5%。在施加这些扭矩时，记录了股直肌、股二头肌、股薄肌、臀中肌、臀大肌、股外侧肌、胫骨前肌和比目鱼肌的肌电图（EMG）活动。描述性分析包括比较代表三组肌肉（正常、偏瘫和非偏瘫肌肉）在每个方向施加扭矩时，受试者的平均肌肉活动的极坐标图（用于髋关节任务）或直方图（用于膝关节任务）。循环统计也用于描述性分析用于描述性分析髋关节任务中每个肌肉的激活方向模式，而线性统计则允许在膝关节任务中分析这些模式。一般来说，无论是描述性还是推论性统计分析的结果都表明，偏瘫患者在髋关节和膝关节扭矩下肌肉激活的方向模式没有改变。这些结果与先前在该人群中对上肢肌肉激活方向模式的研究中观察到的干扰形成对比。有人认为，目前在偏瘫患者上肢和下肢研究结果之间的差异可能反映了上肢和下肢偏瘫肢体运动恢复的差异，或研究关节中受累肌肉的痉挛程度的差异。本研究的结果还表明，偏瘫患者的瘫痪肌肉通常比正常和非瘫痪肌肉产生更大的肌电图信号，尤其是在膝关节屈曲扭矩下。除了一些偏瘫患者无法用其瘫痪肢体完成所有任务的事实外，这些最后观察结果强调了该人群的肌肉无力。
