Soleus stretch reflex modulation during gait in humans
Soleus stretch reflex modulation during gait in humans
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DOI：
10.1152/jn.1996.76.2.1112
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发表时间：
1996-08-01
影响因子：
2.5
通讯作者：
Larsen, B
中科院分区：
文献类型：
--
作者：
Sinkjaer, T;Andersen, JB;Larsen, B
1.研究了不同步行速度对短潜伏期牵张反射的调制，并与健康人站立时的牵张反射进行了比较.踝关节伸展施加的系统能够旋转人类踝关节在跑步机行走在任何阶段的步骤周期。该系统由一个机械关节组成，该关节连接到受试者的踝关节，并通过波顿线连接到放置在跑步机旁边的电机。连接到受试者腿部的整个系统的重量为900 g。短潜伏期比目鱼肌牵张反射在一个步骤中调制。在站立相，振幅等于发现在匹配的比目鱼肌背景肌电图（EMG）站立。在从站立到摆动的过渡中，所有受试者的振幅均为0。在摆动后期，牵张反射振幅增加到站立相最大振幅的45+/-27%（平均值+/-SD）（牵张振幅8度，牵张速度250度/秒）.牵张反射的起始（42+/-3.2 ms）和峰值潜伏期（59+/-2.5 ms）并不依赖于引起反射的步进周期的相位。当踝关节旋转时，可以测量扭矩的变化。在第一个35毫秒后测量的扭矩拉伸发作（无反射扭矩）是在后期的立场，当腿支持了身体的重量的大部分，并在摆动阶段的最小值最大。足跟接触时无反射力矩为最大值的50%.在站立相，最大肌电牵张反射相对于最大背景肌电具有约120 ms的相位超前，相对于最大无反射力矩具有约250 ms的相位超前.在一个步骤中，伸展反射的恒定潜伏期意味着踝伸肌肌梭在行走过程中总是绷紧的。在摆动后期和脚跟接触时的牵张反射的相对高的振幅使得牵张反射可能有助于在早期站立阶段激活踝伸肌。
1. The modulation of the short-latency stretch reflex during walking at different walking speeds was investigated and compared with the stretch reflex during standing in healthy human subjects.2. Ankle joint stretches were applied by a system able to rotate the human ankle joint during treadmill walking in any phase of the step cycle. The system consisted of a mechanical joint attached to the subject's ankle joint and connected to a motor placed beside the treadmill by means of bowden wires. The weight of the total system attached to the leg of the subject was 900 g.3. The short-latency soleus stretch reflex was modulated during a step. In the stance phase, the amplitude equaled that found during standing at matched soleus background electromyogram (EMG). In the transition from stance to swing, the amplitude was 0 in all subjects. In late swing, the stretch reflex amplitude increased to 45+/-27% (mean+/-SD) of the maximal amplitude in the stance phase (stretch amplitude 8 degrees, stretch velocity 250 degrees/s).4. The onset (42+/-3.2 ms) and peak latencies (59+/-2.5 ms) of the stretch reflex did not depend on the phase in the step cycle at which the reflex was elicited.5. When the ankle joint is rotated, a change in torque can be measured. The torque measured over the first 35 ms after stretch onset (nonreflex torque) was at a maximum during late stance, when the leg supported a large part of the body's weight, and at a minimum during the swing phase. At heel contact the nonreflex torque was 50% of its maximal value.6. During the stance phase the maximal EMG stretch reflex had a phase lead of similar to 120 ms with respect to the maximal background EMG and a phase lead of similar to 250 ms with respect to the maximal nonreflex torque.7. The constant latency of the stretch reflex during a step implied that the ankle extensor muscle spindles are always taut during walking.8. The relatively high amplitude of the stretch reflex in late swing and at heel contact made it likely that the stretch reflex contributed to the activation of the ankle extensor muscles in early stance phase.