Changes in hip position modulate soleus H-reflex excitability in man.
Changes in hip position modulate soleus H-reflex excitability in man.
复制标题
髋部位置的变化调节人类比目鱼肌 H 反射的兴奋性。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
A. Arsenault
中科院分区：
文献类型：
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作者：
C. Chapman;S. J. Sullivan;J. Pompura;A. Arsenault
本文研究了11名健康人髋关节屈伸运动对同侧比目鱼肌Hoffmann（H）反射募集曲线的影响。髋关节屈曲（50度），而不是髋关节伸展（15 - 20度），产生H反射的变化。在6/18次会议中观察到维持的促进作用，在产生最大H反射（Hmax）的刺激强度达到峰值。在7/18次治疗中观察到抑制，在Hmax的次最大强度达到峰值。在后面的一些实验中，在高强度刺激（大于Hmax）下也存在促进作用。其余的实验被归类为没有显示效果：3个未调节，但2个显示在高强度刺激（大于Hmax）的促进。由于膝关节在测试位置伸展，因此进行第二系列实验（n = 7），以通过比较膝关节伸展时髋关节屈曲的效果与膝关节屈曲时获得的效果来确定双关节腘绳肌群的伸展对比目鱼肌H反射的可能影响，从而放松腘绳肌。研究结果没有提供证据表明，这种变异性可以解释为不同的相对程度的拉伸腿筋肌肉群。然而，有系统的变化，在相应的控制H-反射募集曲线的形状之间的主题：募集曲线的上升分支的平均斜率是最高的那些实验中显示出抑制，中间无效的实验和最低的那些显示出维持便利。这些观察结果表明，研究的反射输出是不同的，在三个组，可能反映了差异的相对比例的慢，快颤运动单位有助于反射反应。
The effects of hip flexion and extension on the ipsilateral soleus Hoffmann (H) reflex recruitment curve were studied in 11 healthy subjects. Hip flexion (50 degrees), but not hip extension (15-20 degrees), produced changes in the H-reflex. A maintained facilitation, peaking at intensities of stimulation producing a maximal H-reflex (Hmax), was observed in 6/18 sessions. Inhibition, peaking at intensities submaximal for Hmax, was seen in 7/18 sessions. In some of the latter experiments, there was also a facilitation at high intensities of stimulation (greater than Hmax). The remaining experiments were classified as showing no effect: 3 were unmodulated but 2 showed a facilitation at high intensities of stimulation (greater than Hmax). Since the knee was extended in the test position, a second series of experiments (n = 7) were carried out to determine the possible influence of stretch of the biarticular hamstrings muscle group on the soleus H-reflex by comparing the effects of hip flexion with the knee extended with those obtained when the knee was flexed, thereby relaxing the hamstrings. The results provided no evidence that the variability could be explained by differences in the relative degree of stretch on the hamstrings muscle group. There were, however, systematic variations in the shape of the corresponding control H-reflex recruitment curves between subjects: the mean slope of the rising limb of the recruitment curve was highest in those experiments showing an inhibition, intermediate in the ineffective experiments and lowest in those showing a maintained facilitation. These observations indicate that the reflex output studied was different in the three groups, possibly reflecting differences in the relative proportions of slow- and fast-twitch motor units contributing to the reflex response.