title: Modifications in ankle dorsiflexor activation by applying a torque perturbation during walking in persons post-stroke: a case series.
abstract: BACKGROUND
  Results obtained in a previous study (Gait Posture 34:358-363, 2011) have shown that, in non-disabled participants, a specific increase in ankle dorsiflexor (Tibialis anterior [TA]) activation can be induced by walking with a torque perturbation that plantarflexes the ankle during the swing phase. After perturbation removal, the increased TA activation persisted temporarily and was associated with a more dorsiflexed ankle during swing. The objective of the present case-series study was to verify if these results can be reproduced in persons post-stroke.
  
  
  METHODS
  Six participants who sustained a stroke walked on a treadmill before, during and after exposure to a torque perturbation applied at the ankle by a robotized ankle-foot orthosis. Spatiotemporal gait parameters, ankle and knee kinematics, and the electromyographic activity of TA and Soleus were recorded. Mean amplitude of the TA burst located around toe off and peak ankle dorsiflexion angle during swing were compared across the 3 walking periods for each participant.
  
  
  RESULTS
  At the end of the walking period with the perturbation, TA mean amplitude was significantly increased in 4 of the 6 participants. Among these 4 participants, modifications in TA activation persisted after perturbation removal in 3 of them, and led to a statistically significant increase in peak dorsiflexion during swing.
  
  
  CONCLUSIONS
  This approach may be helpful to evaluate the residual adaptive capacity in the ankle dorsiflexors after a stroke and guide decision-making for the selection of optimal rehabilitation interventions. Future work will investigate the clinical impact of a multiple-session gait training based on this approach in persons presenting a reduced ankle dorsiflexion during the swing phase of walking.
authors.forename: Andreanne K
authors.initials: AK
authors.lastname: Blanchette
authors.forename: Martin
authors.initials: M
authors.lastname: Noël
authors.forename: Carol L
authors.initials: CL
authors.lastname: Richards
authors.forename: Sylvie
authors.initials: S
authors.lastname: Nadeau
authors.affiliation: Multidisciplinary Team in Locomotor Rehabilitation, Canadian Institutes of Health Research, Quebec, Canada. laurent.bouyer@rea.ulaval.ca.
authors.forename: Laurent J
authors.initials: LJ
authors.lastname: Bouyer
mesh_terms: D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009989:Orthotic Devices; D012371:Robotics / Q000379:methods; D020521:Stroke / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D019415:Torque; D016138:Walking / Q000502:physiology*