Afferent Contribution to Locomotor Muscle Activity During Unconstrained Overground Human Walking: An Analysis of Triceps Surae Muscle Fascicles
Afferent Contribution to Locomotor Muscle Activity During Unconstrained Overground Human Walking: An Analysis of Triceps Surae Muscle Fascicles
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DOI：
10.1152/jn.00852.2009
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发表时间：
2010-03-01
影响因子：
2.5
通讯作者：
Grey, M. J.
中科院分区：
文献类型：
--
作者：
af Klint, R.;Cronin, N. J.;Grey, M. J.
作者：Klint R，Cronin NJ，石川M，Sinkjaer T，Grey MJ.人在地面上自由行走时运动肌活动的传入贡献：小腿三头肌肌束的分析。神经生理学杂志103：1262-1274，2010。首次发表于2009年12月23日; doi：10.1152/jn.00852.2009。足底屈肌系列弹性可以用来分离肌肉束和肌肉肌腱的行为，从而在人类行走过程中的传入反馈。我们同时使用肌电图（EMG）和高速超声检查来监测19名健康志愿者走过平台时的肌肉活动和肌束行为。在随机试验中，平台相对于水平地面下降（8 cm，0.9 g加速度）或保持在小的倾斜度（在平行平面中高达+/- 3度）。下降的平台在中期和后期阶段的立场产生了抑郁症的比目鱼肌肌肉活动的发病潜伏期约50毫秒。地面反作用力的减少也卸载跖屈肌肌肉。比目鱼肌肌束缩短与最小延迟14毫秒。小的平台倾斜度的变化产生了显着的变化，小腿三头肌肌肉活动; EMG增加时，踩在一个倾斜的表面上，踩在一个下降的表面上时下降。这种运动输出的感觉调节是伴随着小腿三头肌肌束和腓肠肌肌腱长度的变化。假设传入活动与这些机械变化相关，我们的研究结果表明，足底屈肌的步内感觉反馈自动调整肌肉活动，以补偿小的地面不规则性。下降后的平台的延迟开始的肌肉束运动表明，至少初始部分的比目鱼肌抑郁症更有可能介导的减少力反馈比长度敏感的反馈，表明力反馈有助于在人类行走的运动活动。
af Klint R, Cronin NJ, Ishikawa M, Sinkjaer T, Grey MJ. Afferent contribution to locomotor muscle activity during unconstrained over-ground human walking: an analysis of triceps surae muscle fascicles. J Neurophysiol 103: 1262-1274, 2010. First published December 23 2009; doi: 10.1152/jn.00852.2009. Plantar flexor series elasticity can be used to dissociate muscle-fascicle and muscle-tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to +/- 3 degrees in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.