| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Research Institute, Motor Dysfunction Department, National Rehabilitation Center for the Disabled, Tokorozawa, Saitama, Japan
* To whom correspondence should be addressed. E-mail: nakazawa{at}rehab.go.jp.
Recent studies have revealed that the stretch reflex responses of both ankle flexor and extensor muscles are co-augmented in the early stance phase of human walking, suggesting that these co-augmented reflex responses contribute to secure foot stabilization around the heel strike. In order to test whether the reflex responses mediated by the stretch reflex pathway are actually induced in both the ankle flexor and extensor muscles when the supportive surface is suddenly destabilized, we investigated the electromyographic (EMG) responses induced following a sudden drop of the supportive surface at the early stance phase of human walking. While subjects walked on a walkway, the specially designed movable supportive surface was unexpectedly dropped 10 mm during the early stance phase. The results showed that short-latency reflex EMG responses following the impact of the drop (< 50 ms) were consistently observed in both the ankle flexor and extensor muscles in the perturbed leg. Of particular interest was that a distinct response appeared in the tibialis anterior muscle, though this muscle showed little background EMG activity during the stance phase. These results indicated that the reflex activities in the ankle muscles certainly acted when the supportive surface was unexpectedly destabilized just after the heel strike during walking. These reflex responses were most probably mediated by the facilitated stretch reflex pathways of the ankle muscles at the early stance phase and were suggested to be relevant to secure stabilization around the ankle joint during human walking.
This article has been cited by other articles:
|
|
 |
|
  M. H. van der Linden, D. de Kam, B. G. M. van Engelen, H. T. Hendricks, and J. Duysens Fast Responses to Stepping on an Unexpected Surface Height Depend on Intact Large-Diameter Nerve Fibers: A Study on Charcot-Marie-Tooth Type 1A Disease J Neurophysiol, September 1, 2009; 102(3): 1684 - 1698. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. af Klint, J. B. Nielsen, T. Sinkjaer, and M. J. Grey Sudden Drop in Ground Support Produces Force-Related Unload Response in Human Overground Walking J Neurophysiol, April 1, 2009; 101(4): 1705 - 1712. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P.H.J.A. Nieuwenhuijzen and J. Duysens Proactive and Reactive Mechanisms Play a Role in Stepping on Inverting Surfaces During Gait J Neurophysiol, October 1, 2007; 98(4): 2266 - 2273. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. H. van der Linden, D. S. Marigold, F. J.M. Gabreels, and J. Duysens Muscle Reflexes and Synergies Triggered by an Unexpected Support Surface Height During Walking J Neurophysiol, May 1, 2007; 97(5): 3639 - 3650. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
