title: Influence of balance surface on ankle stabilizing muscle activity in subjects with chronic ankle instability.
abstract: OBJECTIVE
  To evaluate the effect of balance surface type on muscle activity of ankle stabilizing muscles in subjects with chronic ankle instability.
  
  
  METHODS
  Case-controlled, repeated-measures study design.
  
  
  METHODS
  Twenty-eight subjects with chronic ankle instability and 28 healthy controls.
  
  
  METHODS
  Subjects performed a barefooted single-legged stance on uniaxial and multidirectional unstable surfaces. Muscle activity of the mm. peroneus longus/brevis, tibialis anterior, gastrocnemius medialis were registered using surface electromyography. Mixed model analysis was used to explore differences in muscle activity between subjects with chronic ankle instability and controls, and the effect of surface type on muscle activity levels within subjects with chronic ankle instability.
  
  
  RESULTS
  No differences were found between subjects with chronic ankle instability and healthy controls. Within subjects with chronic ankle instability, balancing along a frontal axis and on the Both Sides Up evoked overall highest muscle activity level, and the firm surface the least. Balancing on the firm surface showed the lowest tibialis anterior/peroneus longus muscle ratio, followed by balancing along a frontal axis and on the Airex pad.
  
  
  CONCLUSIONS
  Clinicians can use these findings to improve the focus of balance training programmes by gradually progressing in difficulty level based on muscle activation levels taking co-contraction ratios into account.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent Universtiy, BE-9000 Ghent, Belgium. roel.deridder@ugent.be.
authors.forename: Roel
authors.initials: R
authors.lastname: De Ridder
authors.forename: Tine
authors.initials: T
authors.lastname: Willems
authors.forename: Jos
authors.initials: J
authors.lastname: Vanrenterghem
authors.forename: Philip
authors.initials: P
authors.lastname: Roosen
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000473:pathology*; D016022:Case-Control Studies; D004576:Electromyography; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007866:Leg / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D016138:Walking / Q000502:physiology; D055815:Young Adult