Modulations of soleus H-reflex excitability during gait initiation: central versus peripheral influences.
Soleus and tibialis anterior electromyogram (EMG) and soleus H-reflexes were recorded from the stance limb of an individual who suffered a traumatic peroneal nerve injury and of four nonimpaired individuals during gait initiation. The control subjects also initiated walking after swaying forward (sway-gait initiation), which eliminated the initial tibialis anterior activation. During the initial period of gait initiation, H-reflexes were depressed to 43% of standing values during normal-gait initiation and 86% during sway-gait initiation in the nonimpaired subjects. H-reflexes of the nerve-injured subject were depressed to 37%, even though no tibialis anterior EMG was observed. The findings support the view that reciprocal inhibition of the soleus during a task, which normally involves tibialis anterior activation, is due to a centrally mediated process.
Trimble
M H
MH
Department of Physical Therapy, University of Florida, P.O. Box 100154 HSC, Gainesville, Florida 32610-0154, USA.
Brunt
D
D
Jeon
H S
HS
Kim
H D
HD
D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D010543:Peroneal Nerve / Q000293:injuries / Q000502:physiology*; D014836:Volition / Q000502:physiology