title: Multiple sclerosis influences the precision of the ankle plantarflexon muscular force production.
abstract: OBJECTIVE
  To quantify the precision of the steady-state isometric control of the ankle plantarflexors musculature of individuals with multiple sclerosis (MS), and to evaluate if the precision is related to the mobility impairments.
  
  
  METHODS
  Individuals with MS and healthy adults performed a submaximal steady-state isometric contraction with the ankle plantarflexors. The coefficient of variation was used to assess the amount of variability or error in the precision of the torques generated by the ankle plantarflexor musculature. The participants also walked across a digital mat at their preferred and fast-as-possible walking speeds, which recorded their spatiotemporal gait kinematics.
  
  
  RESULTS
  The individuals with MS: (1) had reduced maximal voluntary torques at the ankle, (2) a greater amount of variability in the precision of the isometric ankle torques, (3) altered and more variable spatiotemporal gait kinematics, and (4) a greater amount of variability in the isometric ankle torques were related to a slower walking speed and cadence, shorter step length and a greater amount of gait variability.
  
  
  CONCLUSIONS
  These results further fuels the impression that a reduction in control of the ankle joint musculature may be a key factor in the mobility and balance impairments seen in individuals with MS.
authors.affiliation: Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Arpin
authors.affiliation: Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States.
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Davies
authors.affiliation: Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States. Electronic address: mkurz@unmc.edu.
authors.forename: Max J
authors.initials: MJ
authors.lastname: Kurz
mesh_terms: D000328:Adult; D000842:Ankle; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
keywords: Gait; Isometric; Motor control; Variability; Walking