DIFFERENCE IN THE AMPLITUDE OF THE HUMAN SOLEUS H REFLEX DURING WALKING AND RUNNING
DIFFERENCE IN THE AMPLITUDE OF THE HUMAN SOLEUS H REFLEX DURING WALKING AND RUNNING
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DOI：
10.1113/jphysiol.1987.sp016794
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发表时间：
1987-11-01
影响因子：
5.5
通讯作者：
STEIN, RB
中科院分区：
文献类型：
--
作者：
CAPADAY, C;STEIN, RB
1. 霍夫曼反射，或H反射，在人类比目鱼肌中在步行（4公里/小时）和跑步（8公里/小时）时都被强烈调节。在与脚跟接触时相对较低，在站立阶段逐渐增加，并在站立阶段后期达到最大振幅。踝关节背屈时没有H反射。2. 在跑步时，比目鱼肌的峰值e.m.g.水平平均比走路时高2.4倍，但H反射的最大振幅从未比走路时大。事实上，跑步时的H反射平均显著小于步行时（单尾t检验P < 0.05）。此外，与H反射振幅与背景电图关系拟合的最小二乘线斜率对于步行数据总是比跑步数据更陡。3. 两个任务中H反射的差异证明了H反射的大小不仅仅是。α的被动结果。-运动神经元的兴奋水平，如肌电图所示，但也受到其他中枢神经机制的影响。我们认为突触前抑制是解释斜率变化的最可能的机制。4. 步行和跑步过程中反射的调节可以用自动增益补偿的概念来解释。跑步过程中减少的增益可能适合于减少运动输出的饱和和拉伸反射反馈回路的潜在不稳定性。
1. The Hoffman reflex, or H reflex, was strongly modulated in the human soleus muscle during both walking (4 km/h) and running (8 km/h). It was relatively low at the time of heel contact, increased progressively during the stance phase, and reached its maximum amplitude late in the stance phase. During ankle dorsiflexion the H reflex was absent. 2. During running the peak e.m.g. level of the soleus was on average 2.4 times higher than during walking but the maximum amplitude of the H reflex was never larger than during walking. In fact, the H reflex was on average significantly (P < 0.05 for one-tailed t test) smaller during running than during walking. Furthermore, the slope of the least-squared line fitted to the relation between the H reflex amplitude and the background e.m.g. was always steeper for the walking data than for the running data. 3. The difference in the H reflex in the two tasks is evidence that the size of the H reflex is not simpoly a passive consequence of the .alpha.-motoneurone excitation level, as indicated by the e.m.g., but is also influenced by other central neural mechanisms. We suggest that presynaptic inhibition is the most likely mechanism accounting for the change in the slope. 4. The modulation of the reflexes during walking and running can be interpreted in terms of the idea of automatic gain compensation. The decreased gain during running may be appropriate to reduce saturation of motor output and potential instability of the stretch reflex feed-back loop.