title: Reduced hip extension in the elderly: dynamic or postural?
abstract: OBJECTIVE
  To test the hypothesis that reduced hip extension and increased anterior pelvic tilt in the elderly are dynamic gait phenomena that do not occur during normal standing posture.
  
  
  METHODS
  Experimental.
  
  
  METHODS
  Gait laboratory.
  
  
  METHODS
  Twenty-five older adult subjects (mean age +/- standard deviation, 71+/-5 y) and 25 young adult subjects (mean age, 26+/-5 y).
  
  
  METHODS
  Subjects were observed during standing and walking at self-determined comfortable, slow, and fast walking speeds. Positions and kinematics of the pelvis and lower extremities were measured using a 3-dimensional video-based motion analysis system.
  
  
  METHODS
  Peak hip extension and anterior pelvic tilt.
  
  
  RESULTS
  There were no statistically significant differences between the older and young adult groups during standing with respect to either hip extension (3 degrees +/-5 degrees vs 1 degrees +/-6 degrees) or anterior pelvic tilt (11 degrees +/-5 degrees vs 10 degrees +/-5 degrees). On the other hand, at comfortable walking speeds, the older adult group had reduced peak hip extension (7 degrees +/-6 degrees vs 11 degrees +/-6 degrees , P<.05) and increased anterior pelvic tilt (15 degrees +/-5 degrees vs 11 degrees +/-5 degrees) compared with the young adult group. At fast walking speeds, peak hip extension was significantly reduced in the older adult group than in the young adult group (9 degrees +/-6 degrees vs 14 degrees +/-6 degrees , P<.05), but there was no significant difference at slow walking speeds (6 degrees +/-6 degrees vs 9 degrees +/-5 degrees ).
  
  
  CONCLUSIONS
  Age-related changes in gait defined by reduced peak hip extension and increased pelvic tilt are dynamic rather than standing postural characteristics.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Virginia School of Medicine, Charlottesville, VA 22098-1004, USA. lwl62@virginia.edu
authors.forename: Laura W
authors.initials: LW
authors.lastname: Lee
authors.forename: Keyvan
authors.initials: K
authors.lastname: Zavarei
authors.forename: Jonathan
authors.initials: J
authors.lastname: Evans
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Lelas
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Riley
authors.forename: D Casey
authors.initials: DC
authors.lastname: Kerrigan
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D015577:Geriatric Assessment; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D009142:Musculoskeletal Physiological Phenomena; D004856:Postural Balance / Q000502:physiology*; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology*; D012307:Risk Factors