title: Single-leg drop landing movement strategies in participants with chronic ankle instability compared with lateral ankle sprain 'copers'.
abstract: OBJECTIVE
  To compare the movement patterns and underlying energetics of individuals with chronic ankle instability (CAI) to ankle sprain 'copers' during a landing task.
  
  
  METHODS
  Twenty-eight (age 23.2 ± 4.9 years; body mass 75.5 ± 13.9 kg; height 1.7 ± 0.1 m) participants with CAI and 42 (age 22.7 ± 1.7 years; body mass 73.4 ± 11.3 kg; height 1.7 ± 0.1 m) ankle sprain 'copers' were evaluated 1 year after incurring a first-time lateral ankle sprain injury. Kinematics and kinetics of the hip, knee and ankle joints from 200 ms pre-initial contact (IC) to 200 ms post-IC, in addition to the vertical component of the landing ground reaction force, were acquired during performance of a drop land task.
  
  
  RESULTS
  The CAI group adopted a position of increased hip flexion during the landing descent on their involved limb. This coincided with a reduced post-IC flexor pattern at the hip and increased overall hip joint stiffness compared to copers (-0.01 ± 0.05 vs. 0.02 ± 0.05°/Nm kg(-1), p = 0.03).
  
  
  CONCLUSIONS
  Individuals with CAI display alterations in hip joint kinematics and energetics during a unipodal landing task compared to LAS 'copers'. These alterations may be responsible for the increased risk of injury experienced by individuals with CAI during landing manoeuvres. Thus, clinicians must recognise the potential for joints proximal to the affected ankle to contribute to impaired function following an acute lateral ankle sprain injury and to develop rehabilitation protocols accordingly.
  
  
  METHODS
  Level III.
authors.affiliation: A101, School of Public Health, Physiotherapy and Sport Science, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland. cailbhe.doherty@ucdconnect.ie.
authors.forename: Cailbhe
authors.identifier: http://orcid.org/0000-0002-5284-856X
authors.initials: C
authors.lastname: Doherty
authors.affiliation: Sport and Exercise Sciences Research Institute, Ulster Sports Academy, University of Ulster, Newtownabbey, Co. Antrim, Northern Ireland, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Bleakley
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville, VA, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Hertel
authors.affiliation: A101, School of Public Health, Physiotherapy and Sport Science, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: Caulfield
authors.affiliation: St. Vincent's University Hospital, Dublin 4, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Ryan
authors.affiliation: A101, School of Public Health, Physiotherapy and Sport Science, Health Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.|Institute for Sport and Health, University College Dublin, Dublin 4, Ireland.
authors.forename: Eamonn
authors.initials: E
authors.lastname: Delahunt
mesh_terms: D000222:Adaptation, Physiological; D000223:Adaptation, Psychological; D000328:Adult; D016512:Ankle Injuries / Q000503:physiopathology*; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D005260:Female; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007700:Kinetics; D007719:Knee Joint / Q000503:physiopathology*; D017844:Lateral Ligament, Ankle / Q000293:injuries / Q000503:physiopathology*; D008297:Male; D016059:Range of Motion, Articular; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Ankle joint; Biomechanics; Joint instability; Kinematics; Kinetics; Task performance and analysis