Andersen J B, Sinkjaer T
Center for Sensory-Motor Interaction, Dept. Med. Inform. & Image Analysis, Aalborg Univ., Fredrik Bajers Vej 7D-3, DK-9220 Aalborg, Denmark.
Motor Control. 1999 Apr;3(2):151-7. doi: 10.1123/mcj.3.2.151.
Due to the complexity of applying a well-defined stretch during human walking, most of our knowledge about the short latency stretch reflex modulation in humans is based on H-reflex studies. To illuminate the difference between the two methodologies, both types of reflexes were evoked in the same subjects, same experiment. Stretch reflexes were evoked via a stretch device capable of evoking stretch reflexes of the human soleus muscles during walking. H-reflexes were elicited by an electrical stimulation of the tibial nerve at the popliteal fossa at the knee. A significantly different modulation of the two reflexes was found in the late stance where the stretch reflex decreased in relation to the H-reflex. This was consistent with the unloading of the muscle spindles during the push-off in the late stance, suggesting a complex alpha-gamma coactivation, if any, at this time of the step. The soleus stretch reflex and H-reflex were compared during the stance phase of walking and sitting at matched soleus activity. No difference was found in the amplitude of the stretch reflex. However, there was a significant decrease of the H-reflex during the stance phase of walking, consistent with a task-specific presynaptic mediated reflex control. It is proposed that the short latency stretch reflex during walking is not sensitive to such a presynaptic inhibition.
由于在人类行走过程中施加明确界定的牵张存在复杂性，我们关于人类短潜伏期牵张反射调制的大部分知识都基于Hoffmann反射（H反射）研究。为了阐明这两种方法之间的差异，在同一受试者、同一实验中诱发了这两种反射。牵张反射通过一种能够在行走过程中诱发人类比目鱼肌牵张反射的牵张装置诱发。H反射通过在膝盖腘窝处对胫神经进行电刺激来引出。在站立后期发现这两种反射存在显著不同的调制，其中牵张反射相对于H反射有所下降。这与站立后期蹬离时肌梭卸载一致，表明在该步此时存在复杂的α-γ共同激活（如果有的话）。在行走和坐着的站立阶段，在比目鱼肌活动匹配的情况下比较了比目鱼肌牵张反射和H反射。牵张反射的幅度未发现差异。然而，在行走的站立阶段H反射显著下降，这与任务特异性的突触前介导的反射控制一致。有人提出，行走过程中的短潜伏期牵张反射对这种突触前抑制不敏感。
