title: Lower extremity kinematics of females with patellofemoral pain syndrome while stair stepping.
abstract: METHODS
  Cross-sectional case-control design.
  
  
  BACKGROUND
  Although the etiology of patellofemoral pain syndrome (PFPS) is not completely understood, there is some evidence to suggest that hip position during weight-bearing activities contributes to the disorder.
  
  
  OBJECTIVE
  To compare the knee and hip motions (and their coordination) during stair stepping in female athletes with and without PFPS.
  
  
  METHODS
  Two groups of female recreational athletes, 1 group with PFPS (n = 10) and a control group without PFPS (n = 10), were tested. All participants ascended and descended stairs (condition) at 2 speeds (self-selected comfortable and taxing [defined as 20% faster than the comfortable speed]), while the knee and hip angles were measured with a magnetic-based kinematic data acquisition system. Angle-angle diagrams were used to examine the relationship between flexion/extension of the knee and flexion/extension, adduction/abduction, and internal/external rotation of the hip. The angle of the knee and the 3 angles of the hip at foot contact on the third step were compared between groups by means of 3-way analyses of variance (ANOVA), with repeated measures on speed and condition.
  
  
  RESULTS
  Group-by-speed interaction for knee angle was significant, with knee flexion being greater for the PFPS group for stair ascent and descent at a comfortable speed. Both the angle-angle diagrams and ANOVA demonstrated greater adduction and internal rotation of the hip in the individuals with PFPS compared to control participants during stair descent.
  
  
  CONCLUSIONS
  Compared to control participants, females with PFPS descend stairs with the knee in a more flexed position and have the hip in a more adducted and internally rotated position at foot contact during stair stepping at a comfortable speed.
authors.affiliation: Bachelor of Applied Health Sciences (Athletic Therapy) Program, Sheridan College Institute of Technology and Advanced Learning, Brampton, ON, Canada. kirsty.mckenzie@sheridanc.on.ca
authors.forename: Kirsty
authors.initials: K
authors.lastname: McKenzie
authors.forename: Victoria
authors.initials: V
authors.lastname: Galea
authors.forename: Jean
authors.initials: J
authors.lastname: Wessel
authors.forename: Michael
authors.initials: M
authors.lastname: Pierrynowski
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D016059:Range of Motion, Articular; D055815:Young Adult