title: Kinematic analyses during stair descent in young women with patellofemoral pain.
abstract: BACKGROUND
  Compensatory movement strategies may develop in response to pain to avoid stress on the affected area. Patellofemoral pain is characterised by intermittent periods of pain and the present study addresses whether long-term pain leads to compensatory movement strategies that remain even when the pain is absent.
  
  
  METHODS
  Lower extremity kinematics in three dimensions was studied in stair descent in 17 women with patellofemoral and in 17 matched controls. A two-dimensional geometric model was constructed to normalise kinematic data for subjects with varying anthropometrics when negotiating stairs of fixed proportions.
  
  
  RESULTS
  There were minor differences in movement patterns between groups. Knee joint angular velocity in the stance leg at foot contact was lower and the movement trajectory tended to be jerkier in the patellofemoral group. The two-dimensional model showed greater plantar flexion in the swing leg in preparation for foot placement in the patellofemoral group.
  
  
  CONCLUSIONS
  The results indicate that an altered stair descent strategy in the patellofemoral group may remain also in the absence of pain. The biomechanical interpretation presumes that the strategy is aimed to reduce knee joint loading by less knee joint moment and lower impact force.
authors.affiliation: Dept. of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, SE-901 87 Umeå, Sweden.
authors.forename: Anton
authors.initials: A
authors.lastname: Grenholm
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Stensdotter
authors.forename: Charlotte
authors.initials: C
authors.lastname: Häger-Ross
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000503:physiopathology; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008954:Models, Biological; D010329:Patella / Q000503:physiopathology; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology* / Q000523:psychology; D011597:Psychomotor Performance; D016059:Range of Motion, Articular; D016138:Walking / Q000523:psychology