title: Extensor muscle responses to tibial nerve stimulation are enhanced during dynamic tilts in standing humans.
abstract: We studied the interaction between muscle responses evoked in standing by electrical stimulation (ES) of the tibial nerve and dynamic tilts of the head-and-body in 13 young healthy subjects. Subjects were attached to an L-shaped tilting apparatus and underwent sudden forward tilting of their head-and-body as a whole, without ankle rotation. During such tilts, the area of response evoked in the ipsilateral vastus lateralis (iVL) muscle by the ES was significantly increased by 74% as compared to quiet supported stance (P = 0.01). The response latency of the contralateral VL and soleus muscles i.e. the crossed extension reflex, was significantly shorter during tilt (54 +/- 22 ms) than during quiet supported stance (115 +/- 13 ms, P < 0.01). The increased excitability of extensor muscles activated by ES during tilt seems appropriate to maintain stance during a forward perturbation of the body.
authors.affiliation: School of Physical and Occupational Therapy and Physiology Department, Faculty of Medicine, McGill University, Montreal, Québec, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Paquet
authors.forename: C W
authors.initials: CW
authors.lastname: Hui-Chan
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*