title: The effects of wedged footwear on lower limb frontal plane biomechanics during running.
abstract: OBJECTIVE
  Patellofemoral pain syndrome (PFPS), the most common running injury, has been associated with increased internal knee abduction angular impulses (KAAI). Wedged footwear can reduce these impulses during walking, but their effects during running are not well understood. The purpose of this study was to identify the effects of wedged footwear on KAAIs and describe the mechanism by which wedged footwear alters KAAIs during running.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Motion analysis laboratory.
  
  
  METHODS
  Nine healthy male subjects.
  
  
  METHODS
  Participants ran at a speed of 4 m/s with 7 different footwear conditions (3-, 6-, and 9-mm lateral wedges; 3-, 6-, and 9-mm medial wedges; neutral).
  
  
  METHODS
  Knee abduction angular impulses and 8 predictor variables were measured and compared by 1-way repeated measures analysis of variance (α = 0.05) with Bonferroni-adjusted 2-tailed paired t tests for post hoc analysis (α = 0.002). Correlation (α = 0.05) was used to determine the relationship between the mediolateral center of pressure to ankle joint center (COP-AJC) lever arm length and KAAIs.
  
  
  RESULTS
  Laterally wedged conditions produced significantly lower KAAIs (P = 0.001) than medial wedge conditions. Peak knee abduction moments decreased (P = 0.001), whereas ankle inversion moments (P = 0.041) and the COP-AJC lever arms increased (P < 0.001) as wedges progressed from medial to lateral. KAAIs were negatively correlated with COP-AJC lever arm length (r = -0.50, P < 0.001).
  
  
  CONCLUSIONS
  KAAIs are reduced with laterally wedged footwear because of lateral shifts in the center of pressure beneath the foot, which then increases ankle inversion moments and decreases peak knee abduction moments. Laterally wedged footwear may therefore offer greater relief to runners with PFPS than medially wedged footwear by reducing KAAIs.
authors.affiliation: Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. lewinson@ucalgary.ca
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Lewinson
authors.forename: Claudiane A
authors.initials: CA
authors.lastname: Fukuchi
authors.forename: Jay T
authors.initials: JT
authors.lastname: Worobets
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Stefanyshyn
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D061826:Foot Orthoses / Q000592:standards*; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D046788:Patellofemoral Pain Syndrome / Q000209:etiology / Q000517:prevention & control*; D012420:Running / Q000293:injuries*; D012775:Shoes; D055815:Young Adult