The role of joint biomechanics in determining stretch reflex latency at the normal human ankle
The role of joint biomechanics in determining stretch reflex latency at the normal human ankle
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关节生物力学在确定正常人踝关节牵张反射潜伏期中的作用
DOI：
10.1007/bf00250575
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发表时间：
2004
影响因子：
2
通讯作者：
A. Thilmann
中科院分区：
文献类型：
--
作者：
S. Fellows;A. Thilmann
为了研究生物力学因素对踝关节伸肌群牵张反射活动时间的影响，在生理运动范围内，以一系列角度对正常人的踝关节施加定义明确的、小幅度的和相对快速的背屈牵张。如果踝关节肌肉组织是放松的，一个单一的反射组件出现在小腿三头肌（TS）肌电图的潜伏期兼容的主要单突触通路。这种反应的潜伏期可以通过从最初的跖屈位置施加拉伸而延长，并且类似地，通过从背屈位置施加拉伸而减少。通过将位移前踝关节角度从105度改变到75度，可以实现5-30 ms的潜伏期减少。起始角度的中间变化导致潜伏期的中间变化。这种趋势是高度线性的。然而，如果在受试者保持TS低水平收缩的同时施加拉伸，则潜伏期的这种变化被消除，最早的反射成分出现在放松状态下或接近最大背屈时的潜伏期。有人建议，这种转变的潜伏期的结果，从属性的长，顺应性肌腱，通过该关节运动传输到TS肌肉。当对机械输入引起的反射进行分类时，或者当使用潜伏期测定作为其起源中涉及特定通路的证据时，应考虑到由诱发反射的踝关节角度的被动改变引起的潜伏期的这种变化。
SummaryIn order to study the influence of biomechanical factors on the timing of stretch reflex activity in the ankle extensor musculature, well defined, small amplitude and relatively rapid dorsiflexing stretch was applied to the ankle of seated normal human subjects at a series of angles within the range of physiological movement. If the ankle musculature was relaxed, a single reflex component appeared in the Triceps surae (TS) EMG with a latency compatible with a predominantly monosynaptic pathway. The latency of this response could be prolonged by applying stretch from an initially plantarflexed position and, similarly, decreased by applying stretch from a dorsiflexed position. A decrease in latency of 5–30 ms could be achieved by altering the pre-displacement ankle angle from 105 to 75 degrees. Intermediate changes in the start angle led to intermediate changes in latency. This trend was highly linear. If stretch was applied while the subject maintained a low level contraction in the TS, however, this shift in latency was abolished, with the earliest reflex components appearing with a latency obtained in the relaxed state at or close to maximum dorsiflexion. It is suggested that this shift in latency results from the properties of the long, compliant tendon through which joint movements are transmitted to the TS muscle. This shift in latency caused by passive alteration in the ankle angle at which a reflex was evoked should be taken into account when classifying reflexes arising from a mechanical input, or when using latency determinations as evidence for the involvement of particular pathways in their genesis.