title: Multi-segment foot landing kinematics in subjects with chronic ankle instability.
abstract: BACKGROUND
  Chronic ankle instability has been associated with altered joint kinematics at the ankle, knee and hip. However, no studies have investigated possible kinematic deviations at more distal segments of the foot. The purpose of this study was to evaluate if subjects with ankle instability and copers show altered foot and ankle kinematics and altered kinetics during a landing task when compared to controls.
  
  
  METHODS
  Ninety-six subjects (38 subjects with chronic ankle instability, 28 copers and 30 controls) performed a vertical drop and side jump task. Foot kinematics were obtained using the Ghent Foot Model and a single-segment foot model. Group differences were evaluated using statistical parametric mapping and analysis of variance.
  
  
  RESULTS
  Subjects with ankle instability had a more inverted midfoot position in relation to the rearfoot when compared to controls during the side jump. They also had a greater midfoot inversion/eversion range of motion than copers during the vertical drop. Copers exhibited less plantar flexion/dorsiflexion range of motion in the lateral and medial forefoot. Furthermore, the ankle instability and coper group exhibited less ankle plantar flexion at touchdown. Additionally, the ankle instability group demonstrated a decreased plantar flexion/dorsiflexion range of motion at the ankle compared to the control group. Analysis of ground reaction forces showed a higher vertical peak and loading rate during the vertical drop in subjects with ankle instability.
  
  
  CONCLUSIONS
  Subjects with chronic ankle instability displayed an altered, stiffer kinematic landing strategy and related alterations in landing kinetics, which might predispose them for episodes of giving way and actual ankle sprains.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent University, De Pintelaan 185, Ghent 9000, Belgium. Electronic address: Roel.Deridder@ugent.be.
authors.forename: Roel
authors.initials: R
authors.lastname: De Ridder
authors.affiliation: Department of Physiotherapy and Orthopedics, Ghent University, De Pintelaan 185, Ghent 9000, Belgium. Electronic address: Tine.Willems@ugent.be.
authors.forename: Tine
authors.initials: T
authors.lastname: Willems
authors.affiliation: Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. Electronic address: J.Vanrenterghem@ljmu.ac.uk.
authors.forename: Jos
authors.initials: J
authors.lastname: Vanrenterghem
authors.affiliation: Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. Electronic address: M.A.Robinson@ljmu.ac.uk.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Robinson
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent University, De Pintelaan 185, Ghent 9000, Belgium. Electronic address: Tanneke.Palmans@ugent.be.
authors.forename: Tanneke
authors.initials: T
authors.lastname: Palmans
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent University, De Pintelaan 185, Ghent 9000, Belgium. Electronic address: Philip.Roosen@ugent.be.
authors.forename: Philip
authors.initials: P
authors.lastname: Roosen
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000209:etiology; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D016059:Range of Motion, Articular; D012307:Risk Factors; D055815:Young Adult
keywords: 3D kinematics; Ankle instability; Foot segments; Impact phase