title: Inhibition of soleus Hoffmann reflex by ankle-foot orthosis application in healthy volunteers.
abstract: BACKGROUND
  An ankle-foot orthosis is suggested to actively assist dorsiflexion of the foot by induction of a positive proprioceptive impact to ankle dorsiflexor muscles. However, an objective proof is missing.
  
  
  OBJECTIVE
  To assess the proprioceptive impact of an ankle-foot orthosis application by Hoffmann reflex recordings of the soleus muscle under static conditions. It was hypothesized that the use of an ankle-foot orthosis facilitated dorsiflexor motor function and thus a decreased the soleus Hoffmann reflex.
  
  
  METHODS
  Experimental study in healthy volunteers, pre-post test design.
  
  
  METHODS
  In all, 20 healthy volunteers were enrolled in order to assess the proprioceptive impact of orthosis application. The Hoffmann reflex was recorded before, during, and after orthosis application.
  
  
  RESULTS
  Under orthosis application, the Hoffmann reflex significantly decreased as compared to before (p < 0.05) and after application (p < 0.05).
  
  
  CONCLUSIONS
  Findings indicate an inhibition of plantarflexors probably induced by facilitation of ankle dorsiflexors under static conditions. At first glance, it seems that foot orthoses primarily have a stabilizing effect on ankle joints in terms of simple mechanical bandages. However, the present results suggest an additional active impact on proprioceptive control.
  
  
  CONCLUSIONS
  The putative neuromodulatory effect on motor control may support the application of such ankle-foot orthoses in, for example, drop foot. Furthermore, the objective assessment of a neurophysiological mode of action of orthoses by Hoffmann reflex recordings might be an appropriate primary outcome parameter in clinical trials.
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Department of Neurology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Lars E
authors.initials: LE
authors.lastname: Larsen
authors.affiliation: Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark.
authors.forename: Lydia A
authors.initials: LA
authors.lastname: Jakobsen
authors.affiliation: Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Jensen
authors.affiliation: Hull York Medical School, University of Hull, Hull, UK.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Lambden
authors.affiliation: Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark.
authors.forename: Morten R
authors.initials: MR
authors.lastname: Sørensen
authors.affiliation: Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark jellrich@hst.aau.dk.
authors.forename: Jens
authors.initials: J
authors.lastname: Ellrich
mesh_terms: D000704:Analysis of Variance; D000842:Ankle / Q000502:physiology; D005260:Female; D005528:Foot / Q000502:physiology; D061826:Foot Orthoses; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D012016:Reference Values; D012021:Reflex, Abnormal / Q000502:physiology*; D055815:Young Adult
keywords: Hoffmann reflex; proprioception; soleus; tibialis anterior