title: A soft ankle brace increases soleus Hoffman reflex amplitude but does not modify presynaptic inhibition during upright standing.
abstract: External ankle supports, such as ankle braces, may improve postural stability by stimulating cutaneous receptors. It remains unknown whether these supports have an effect on the posture central regulation. The aim of this study was to determine the effect of wearing a soft ankle brace on soleus H-reflex amplitude and presynaptic inhibition during standing. Sixteen subjects stood on a rigid floor with their eyes opened, either barefoot or wearing a soft ankle brace. H-reflex amplitude was measured on the soleus muscle by stimulating the tibial nerve electrically. Modulation of presynaptic inhibition was assessed by conditioning the H-reflex with fibular nerve (D1 inhibition) and femoral nerve (heteronymous facilitation) electrical stimulations. The unconditioned H-reflex amplitude was significantly greater when wearing the ankle brace than barefoot, whereas D1 and HF conditioned soleus H-reflex did not differ significantly between bracing conditions. These results suggest that the ankle brace increased the soleus motoneuron excitability without altering presynaptic mechanisms, potentially because of increased cutaneous mechanoreceptors afferent signals provided by the soft ankle brace.
authors.affiliation: Université Savoie Mont Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-73000 Chambéry, France; Salomon SAS, Amer Sports Footwear Innovation and Sport Science Lab, 14 chemin des Croiselets, 74996 Annecy, Cedex 9, France. Electronic address: sebastien.pavailler@univ-savoie.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Pavailler
authors.affiliation: Université Savoie Mont Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-73000 Chambéry, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Forestier
authors.affiliation: Université Savoie Mont Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-73000 Chambéry, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Hintzy
authors.affiliation: Université Savoie Mont Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-73000 Chambéry, France; Salomon SAS, Amer Sports Footwear Innovation and Sport Science Lab, 14 chemin des Croiselets, 74996 Annecy, Cedex 9, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Horvais
authors.affiliation: Univ Lyon, UJM-Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-42023, SAINT-ETIENNE, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lapole
mesh_terms: D000328:Adult; D000842:Ankle; D000843:Ankle Joint / Q000502:physiology*; D001915:Braces; D004558:Electric Stimulation; D004576:Electromyography; D004867:Equipment Design; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D011187:Posture / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology; D055815:Young Adult
keywords: Cutaneous stimulation; D1 inhibition; Heteronymous facilitation; Posture regulation; Surface electromyography; Tibial nerve