Major role for sensory feedback in soleus EMG activity in the stance phase of walking in man
Sensory feedback plays a major role in the regulation of the spinal neural locomotor circuitry in cats. The present study investigated whether sensory feedback also plays an important role during walking in 20 healthy human subjects, by arresting or unloading the ankle extensors 6 deg for 210 ms in...
Saved in:
Published in | The Journal of physiology Vol. 523; no. 3; pp. 817 - 827 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
The Physiological Society
15.03.2000
Blackwell Science Ltd Blackwell Science Inc |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Sensory feedback plays a major role in the regulation of the spinal neural locomotor circuitry in cats. The present study
investigated whether sensory feedback also plays an important role during walking in 20 healthy human subjects, by arresting
or unloading the ankle extensors 6 deg for 210 ms in the stance phase of gait.
During the stance phase of walking, unloading of the ankle extensors significantly ( P < 0·05) reduced the soleus activity by 50 % in early and mid-stance at an average onset latency of 64 ms.
The onset and amplitude of the decrease in soleus activity produced by the unloading were unchanged when the common peroneal
nerve, which innervates the ankle dorsiflexors, was reversibly blocked by local injection of lidocaine ( n = 3). This demonstrated that the effect could not be caused by a peripherally mediated reciprocal inhibition from afferents
in the antagonist nerves.
The onset and amplitude of the decrease in soleus activity produced by the unloading were also unchanged when ischaemia was
induced in the leg by inflating a cuff placed around the thigh. At the same time, the group Ia-mediated short latency stretch
reflex was completely abolished. This demonstrated that group Ia afferents were probably not responsible for the decrease
of soleus activity produced by the unloading.
The findings demonstrate that afferent feedback from ankle extensors is of significant importance for the activation of these
muscles in the stance phase of human walking. Group II and/or group Ib afferents are suggested to constitute an important
part of this sensory feedback. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1111/j.1469-7793.2000.00817.x |