title: Ankle dynamic in stroke patients: agonist vs. antagonist muscle relations.
abstract: BACKGROUND
  Atypical ankle patterns of muscle activity during gait are commonly reported in patients with stroke. These findings can be due to changes between tibialis anterior (TA) and soleus (SOL) coactivation mechanisms.
  
  
  OBJECTIVE
  To compare the electromyographic activity (EMGa) of SOL and TA muscles and antagonist coactivation (C) level in the contralateral (CONTRA) and ipsilateral (IPSI) limbs to the side of the stroke lesion during the stance phase of the gait cycle.
  
  
  METHODS
  Twelve subjects with a stroke episode participated in this study. The electromyographic signal of TA and SOL and ground reaction forces were acquired while subjects walked at their self-selected speed. Values of ground reaction forces were used to divide the stance phase of gait into initial contact, midstance, and terminal stance. In each sub-phase, the magnitude of TA and SOL was calculated as well as the level of the antagonist C.
  
  
  RESULTS
  Although no statistical differences were found, mean values of SOL EMGa were lower in the IPSI limb in all stance phases in relation to the CONTRA limb, and the opposite was observed in the TA EMGa. Moreover, higher mean levels of antagonist C were only found during the initial contact sub-phase in the CONTRA limb and in the other sub-phases in the IPSI limb. Besides, statistical differences were observed only during midstance.
  
  
  CONCLUSIONS
  In stroke subjects, the antagonist C level during midstance of gait may reflect the dysfunction of the neuronal system over the IPSI limb.
authors.affiliation: Área Científica de Fisioterapia, Escola Superior de Tecnologia da Saúde do Instituto Politécnico do Porto, Vila Nova de Gaia, Portugal. smaugusta@gmail.com
authors.forename: Augusta
authors.initials: A
authors.lastname: Silva
authors.forename: Andreia S P
authors.initials: AS
authors.lastname: Sousa
authors.forename: João Manuel R S
authors.initials: JM
authors.lastname: Tavares
authors.forename: Ana
authors.initials: A
authors.lastname: Tinoco
authors.forename: Rubim
authors.initials: R
authors.lastname: Santos
authors.forename: Filipa
authors.initials: F
authors.lastname: Sousa
mesh_terms: D000842:Ankle / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology*