title: Weight-Bearing Dorsiflexion Range of Motion and Landing Biomechanics in Individuals With Chronic Ankle Instability.
abstract: BACKGROUND
  People with chronic ankle instability (CAI) exhibit less weight-bearing dorsiflexion range of motion (ROM) and less knee flexion during landing than people with stable ankles. Examining the relationship between dorsiflexion ROM and landing biomechanics may identify a modifiable factor associated with altered kinematics and kinetics during landing tasks.
  
  
  OBJECTIVE
  To examine the relationship between weight-bearing dorsiflexion ROM and single-legged landing biomechanics in persons with CAI.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  Fifteen physically active persons with CAI (5 men, 10 women; age = 21.9 ± 2.1 years, height = 168.7 ± 9.0 cm, mass = 69.4 ± 13.3 kg) participated.
  
  
  METHODS
  Participants performed dorsiflexion ROM and single-legged landings from a 40-cm height. Sagittal-plane kinematics of the lower extremity and ground reaction forces (GRFs) were captured during landing.
  
  
  METHODS
  Static dorsiflexion was measured using the weight-bearing-lunge test. Kinematics of the ankle, knee, and hip were observed at initial contact, maximum angle, and sagittal displacement. Sagittal displacements of the ankle, knee, and hip were summed to examine overall sagittal displacement. Kinetic variables were maximum posterior and vertical GRFs normalized to body weight. We used Pearson product moment correlations to evaluate the relationships between dorsiflexion ROM and landing biomechanics. Correlations (r) were interpreted as weak (0.00-0.40), moderate (0.41-0.69), or strong (0.70-1.00). The coefficient of determination (r(2)) was used to determine the amount of explained variance among variables.
  
  
  RESULTS
  Static dorsiflexion ROM was moderately correlated with maximum dorsiflexion (r = 0.49, r(2) = 0.24), ankle displacement (r = 0.47, r(2) = 0.22), and total displacement (r = 0.67, r(2) = 0.45) during landing. Dorsiflexion ROM measured statically and during landing demonstrated moderate to strong correlations with maximum knee (r = 0.69-0.74, r(2) = 0.47-0.55) and hip (r = 0.50-0.64, r(2) = 0.25-0.40) flexion, hip (r = 0.53-0.55, r(2) = 0.28-0.30) and knee (r = 0.53-0.70, r(2) = 0.28-0.49) displacement, and vertical GRF (-0.47- -0.50, r(2) = 0.22-0.25).
  
  
  CONCLUSIONS
  Dorsiflexion ROM was moderately to strongly related to sagittal-plane kinematics and maximum vertical GRF during single-legged landing in persons with CAI. Persons with less dorsiflexion ROM demonstrated a more erect landing posture and greater GRF.
authors.affiliation: Old Dominion University, Norfolk, VA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Hoch
authors.affiliation: Old Dominion University, Norfolk, VA.
authors.forename: Kelley E
authors.initials: KE
authors.lastname: Farwell
authors.affiliation: Franklin College, IN.
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Gaven
authors.affiliation: Old Dominion University, Norfolk, VA.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Weinhandl
mesh_terms: D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: ankle sprain; drop landing; kinematics; kinetics; neuromuscular control