title: Influence of Q-angle on lower-extremity running kinematics.
abstract: METHODS
  Two-group posttest-only comparison.
  
  
  OBJECTIVE
  To assess the influence of the Q-angle on the 3-dimensional lower-extremity kinematics during running.
  
  
  BACKGROUND
  An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. Previous investigations using 2-dimensional analyses during walking did not support this hypothesis.
  
  
  METHODS
  We hypothesized that individuals with Q-angles more than 15 degrees would display an increase in rearfoot eversion and tibial internal rotation during running. Thirty-two nonimpaired subjects (men: n = 16, mean age = 22 +/- 3 years; women: n = 16, mean age = 23 +/- 3 years) ran over ground, and 3-dimensional kinematic data were collected from the right lower extremity. Subjects with a Q-angle of 15 degrees or less comprised the low-Q-angle group, whereas those with Q-angles of more than 15 degrees comprised the high-Q-angle group. Segment and joint maximum angles and the times when the maxima occurred during stance were measured.
  
  
  RESULTS
  The Q-angle magnitude did not increase the maximum segment or joint angles during running. The groups displayed similar maximum angles for rearfoot eversion (low Q-angle, -15.5 +/- 5.0 degrees; high Q-angle, -15.6 +/- 6.6 degrees) and tibial internal rotation (low Q-angle, -8.8 +/- 4.8 degrees; high Q-angle, -6.8 +/- 5.1 degrees). The high-Q-angle group (39.5 +/- 16.3%) achieved maximum tibial internal rotation later in the stance phase than the low-Q-angle group (28.8 +/- 10.7%).
  
  
  CONCLUSIONS
  In support of the previous investigations involving Q-angle influences on kinematics, our study did not reveal any differences between groups in maximum joint or segment angles. The kinematic information did reveal that the high-Q-angle group displayed an increase in time to maximum tibial internal rotation. The impact of this single factor on producing knee injury is unknown.
authors.affiliation: Department of Exercise Science, University of Massachusetts, Amherst 01003, USA. bcheider@excsci.umass.edu
authors.forename: B C
authors.initials: BC
authors.lastname: Heiderscheit
authors.forename: J
authors.initials: J
authors.lastname: Hamill
authors.forename: G E
authors.initials: GE
authors.lastname: Caldwell
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012399:Rotation; D012420:Running / Q000502:physiology*; D014741:Video Recording; D016138:Walking / Q000502:physiology*