title: Hip and knee flexion of lead and trail limbs during ascent of a step of different heights by normal adults.
abstract: OBJECTIVE
  To describe and compare hip and knee flexion of the lead and trail limbs during step ascent.
  
  
  METHODS
  Descriptive observational study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Fourteen healthy subjects.
  
  
  METHODS
  A seven-camera tracking system captured the kinematics of the lead and trail limbs as subjects ascended 20.3-cm and 40.6-cm steps, leading with each lower limb. Maximum hip and knee flexion were recorded bilaterally.
  
  
  RESULTS
  During ascent of the 20.3-cm step, mean flexion was 66.3 degrees for the lead hips and 20.6 degrees for the trail hips [mean difference 45.7 degrees , 95% confidence interval (CI) 43.5 degrees to 48.0 degrees]. During ascent of the 40.6-cm step, mean flexion was 92.5 degrees for the lead hips and 26.8 degrees for the trail hips (mean difference 65.6 degrees, 95% CI 62.1 degrees to 69.1 degrees). During ascent of the 20.3-cm step, mean flexion was 90.5 degrees for the lead knees and 57.6 degrees for the trail knees (mean difference 32.9 degrees , 95% CI 29.3 degrees to 36.5 degrees). During ascent of the 40.6-cm step, mean flexion was 119.9 degrees for the lead knees and 73.2 degrees for the trail knees (mean difference 46.7 degrees , 95% CI 41.9 degrees to 51.5 degrees). A general linear model revealed that for both the hip and the knee, flexion was significantly greater in the lead limb than in the trail limb, and during ascent of the 40.6-cm step compared with the 20.3-cm step.
  
  
  CONCLUSIONS
  The hip and knee flexion used to ascend a step depends on whether a limb is leading or trailing, and on step height. For individuals with limited flexion in a limb, range demands will be reduced if the restricted limb trails during a step-to-step pattern.
authors.affiliation: Physical Therapy and Sports Medicine Centers, Watertown, CT, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Smutnick
authors.forename: Richard W
authors.initials: RW
authors.lastname: Bohannon
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D016014:Linear Models; D008124:Locomotion / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D016138:Walking / Q000502:physiology