title: Fatigue-induced alterations of static and dynamic postural control in athletes with a history of ankle sprain.
abstract: BACKGROUND
  Sensorimotor control is impaired after ankle injury and in fatigued conditions. However, little is known about fatigue-induced alterations of postural control in athletes who have experienced an ankle sprain in the past.
  
  
  OBJECTIVE
  To investigate the effect of fatiguing exercise on static and dynamic balance abilities in athletes who have successfully returned to preinjury levels of sport activity after an ankle sprain.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  University sport science research laboratory.
  
  
  METHODS
  30 active athletes, 14 with a previous severe ankle sprain (return to sport activity 6-36 months before study entry; no residual symptoms or subjective instability) and 16 uninjured controls.
  
  
  METHODS
  Fatiguing treadmill running in 2 experimental sessions to assess dependent measures.
  
  
  METHODS
  Center-of-pressure sway velocity in single-legged stance and time to stabilization (TTS) after a unilateral jump-landing task (session 1) and maximum reach distance in the Star Excursion Balance Test (SEBT) (session 2) were assessed before and immediately after a fatiguing treadmill exercise. A 2-factorial linear mixed model was specified for each of the main outcomes, and effect sizes (ESs) were calculated as Cohen d.
  
  
  RESULTS
  In the unfatigued condition, between-groups differences existed only for the anterior-posterior TTS (P = .05, ES = 0.39). Group-by-fatigue interactions were found for mean SEBT (P = .03, ES = 0.43) and anterior-posterior TTS (P = .02, ES = 0.48). Prefatigue versus postfatigue SEBT and TTS differences were greater in previously injured athletes, whereas static sway velocity increased similarly in both groups.
  
  
  CONCLUSIONS
  Fatiguing running significantly affected static and dynamic postural control in participants with a history of ankle sprain. Fatigue-induced alterations of dynamic postural control were greater in athletes with a previous ankle sprain. Thus, even after successful return to competition, ongoing deficits in sensorimotor control may contribute to the enhanced ankle reinjury risk.
authors.affiliation: Institute of Sport Science and Sport, University of Erlangen-Nuremberg, Erlangen, Germany. simon.steib@sport.uni-erlangen.de
authors.forename: Simon
authors.initials: S
authors.lastname: Steib
authors.forename: Astrid
authors.initials: A
authors.lastname: Zech
authors.forename: Christian
authors.initials: C
authors.lastname: Hentschke
authors.forename: Klaus
authors.initials: K
authors.lastname: Pfeifer
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D056352:Athletes; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D009068:Movement / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013180:Sprains and Strains / Q000503:physiopathology*