title: Attentional demands and postural sway: the effect of the calf muscles fatigue.
abstract: OBJECTIVE
  The purpose of the present experiment was to investigate whether the calf muscle fatigue affects postural sway in bipedal stance and requires additional attentional demands.
  
  
  METHODS
  Nine healthy university students had to respond as rapidly as possible to an unpredictable auditory stimulus while maintaining stable seated and upright postures with their eyes closed in two conditions of no-fatigue and fatigue of the calf muscles. Center of foot pressure (COP) displacements were recorded using a force platform. Reaction times (RTs) values were used as an index of the attentional demand necessary for regulating postural sway.
  
  
  RESULTS
  Fatigue yielded a significant anterior shift of mean position of the COP and increased range, mean speed, and dispersion of COP displacements. An increased attentional demand for regulating postural sway also was observed with fatigue.
  
  
  CONCLUSIONS
  These results suggest that muscular fatigue may put the individuals at higher risk of falling, especially when engaging in concurrent tasks.
authors.affiliation: Laboratoire Sport et Performance Motrice, Université Joseph Fourier, BP 53, 38041 Grenoble cedex 9, France. Nicolas.Vuillerme@ujf-grenoble.fr
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vuillerme
authors.forename: Nicolas
authors.initials: N
authors.lastname: Forestier
authors.forename: Vincent
authors.initials: V
authors.lastname: Nougier
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000842:Ankle / Q000503:physiopathology; D001288:Attention / Q000502:physiology*; D005528:Foot / Q000503:physiopathology; D006801:Humans; D009068:Movement / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D011187:Posture / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D012016:Reference Values