title: Using Balance Tests to Discriminate Between Participants With a Recent Index Lateral Ankle Sprain and Healthy Control Participants: A Cross-Sectional Study.
abstract: BACKGROUND
  The first step to identifying factors that increase the risk of recurrent ankle sprains is to identify impairments after a first sprain and compare performance with individuals who have never sustained a sprain. Few researchers have restricted recruitment to a homogeneous group of patients with first sprains, thereby introducing the potential for confounding.
  
  
  OBJECTIVE
  To identify impairments that differ in participants with a recent index lateral ankle sprain versus participants with no history of ankle sprain.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  We recruited a sample of convenience from May 2010 to April 2013 that included 70 volunteers (age = 27.4 ± 8.3 years, height = 168.7 ± 9.5 cm, mass = 65.0 ± 12.5 kg) serving as controls and 30 volunteers (age = 31.1 ± 13.3 years, height = 168.3 ± 9.1 cm, mass = 67.3 ± 13.7 kg) with index ankle sprains.
  
  
  METHODS
  We collected demographic and physical performance variables, including ankle-joint range of motion, balance (time to balance after perturbation, Star Excursion Balance Test, foot lifts during single-legged stance, demi-pointe balance test), proprioception, motor planning, inversion-eversion peak power, and timed stair tests. Discriminant analysis was conducted to determine the relationship between explanatory variables and sprain status. Sequential discriminant analysis was performed to identify the most relevant variables that explained the greatest variance.
  
  
  RESULTS
  The average time since the sprain was 3.5 ± 1.5 months. The model, including all variables, correctly predicted a sprain status of 77% (n = 23) of the sprain group and 80% (n = 56) of the control group and explained 40% of the variance between groups ([Formula: see text] = 42.16, P = .03). Backward stepwise discriminant analysis revealed associations between sprain status and only 2 tests: Star Excursion Balance Test in the anterior direction and foot lifts during single-legged stance ([Formula: see text] = 15.2, P = .001). These 2 tests explained 15% of the between-groups variance and correctly predicted group membership of 63% (n = 19) of the sprain group and 69% (n = 48) of the control group.
  
  
  CONCLUSIONS
  Balance impairments were associated with a recent first ankle sprain, but proprioception, motor control, power, and function were not.
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Pourkazemi
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Claire
authors.initials: C
authors.lastname: Hiller
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Raymond
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Deborah
authors.initials: D
authors.lastname: Black
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Nightingale
authors.affiliation: The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Refshauge
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005528:Foot / Q000502:physiology; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D016059:Range of Motion, Articular; D012008:Recurrence; D012307:Risk Factors; D013180:Sprains and Strains / Q000503:physiopathology*; D055815:Young Adult
keywords: index inversion ankle sprain; inversion-eversion peak power; proprioception