Major role for sensory feedback in soleus EMG activity in the stance phase of walking in man
Article first published online: 12 AUG 2004
The Journal of Physiology
Volume 523, Issue 3, pages 817–827, March 2000
How to Cite
Sinkjær, T., Andersen, J. B., Ladouceur, M., Christensen, L. O. D. and Nielsen, J. B. (2000), Major role for sensory feedback in soleus EMG activity in the stance phase of walking in man. The Journal of Physiology, 523: 817–827. doi: 10.1111/j.1469-7793.2000.00817.x
- Issue published online: 13 AUG 2004
- Article first published online: 12 AUG 2004
- (Received 30 June 1999; accepted after revision 7 December 1999)
- 1Sensory 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.
- 2During 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.
- 3The 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.
- 4The 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.
- 5The 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.