Gemperline J J, Allen S, Walk D, Rymer W Z
Sensory Motor Performance Program, Rehabilitation Institute of Chicago, IL 60611, USA.
Muscle Nerve. 1995 Oct;18(10):1101-14. doi: 10.1002/mus.880181006.
We studied the discharge rates and recruitment characteristics of single motor units in paretic and contralateral arm muscles of 6 hemiparetic subjects. Motor unit activity in biceps brachii was recorded at different elbow torques, and the activity related both to the mean level of surface electromyographic activity, and to the degree of weakness. In 3 of the 6 subjects, there were significant reductions in mean discharge rate of motor units in the paretic muscle. All 6 subjects showed compression of the range of motoneuron recruitment forces, and a failure to increase motor unit discharge rate during voluntary force increases in paretic muscles. These rate reductions could potentially alter the precise match of motoneuron properties to the mechanical properties of the innervated muscle fibers, and reduce the efficiency of muscle contraction. This reduction could lead, in turn to increased effort, to fatigue, and ultimately to a sense of weakness for voluntary force generation.
我们研究了6名偏瘫患者患侧和对侧手臂肌肉中单个运动单位的放电率和募集特征。在不同的肘部扭矩下记录肱二头肌的运动单位活动，该活动与表面肌电图活动的平均水平以及虚弱程度均有关。6名受试者中有3名患侧肌肉运动单位的平均放电率显著降低。所有6名受试者均表现出运动神经元募集力范围的压缩，并且在患侧肌肉主动用力增加期间，运动单位放电率未能增加。这些放电率降低可能会潜在地改变运动神经元特性与所支配肌纤维机械特性的精确匹配，并降低肌肉收缩效率。这种降低进而可能导致用力增加、疲劳，并最终导致主动用力产生时的虚弱感。
