title: Take your shoes off to reduce patellofemoral joint stress during running.
abstract: OBJECTIVE
  Elevated patellofemoral joint stress is thought to contribute to the development and progression of patellofemoral pain syndrome. The purpose of this study was to determine if running barefoot decreases patellofemoral joint stress in comparison to shod running.
  
  
  METHODS
  Lower extremity kinematics and ground reaction force data were collected from 22 trained runners during overground running while barefoot and in a neutral running shoe. The kinematic and kinetic data were used as input variables into a previously described mathematical model to determine patellofemoral joint stress. Knee flexion angle, net knee extension moment and the model outputs of contact area, patellofemoral joint reaction force and patellofemoral joint stress were plotted over the stance phase of the gait cycle and peak values compared using paired t tests and standardised mean differences calculated.
  
  
  RESULTS
  Running barefoot decreased peak patellofemoral joint stress by 12% (p=0.000) in comparison to shod running. The reduction in patellofemoral joint stress was a result of reduced patellofemoral joint reaction forces (12%, p=0.000) while running barefoot.
  
  
  CONCLUSIONS
  Elevated patellofemoral joint stress during shod running might contribute to patellofemoral pain. Running barefoot decreases patellofemoral joint stress.
authors.affiliation: Centre for Exercise and Sports Science, School of Exercise and Nutrition Sciences, Deakin University, , Geelong, Victoria, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Bonacci
authors.forename: Bill
authors.initials: B
authors.lastname: Vicenzino
authors.forename: Wayne
authors.initials: W
authors.lastname: Spratford
authors.forename: Paul
authors.initials: P
authors.lastname: Collins
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D057071:Patellofemoral Joint / Q000502:physiology*; D046788:Patellofemoral Pain Syndrome / Q000209:etiology / Q000503:physiopathology; D012420:Running / Q000502:physiology*; D012775:Shoes; D013312:Stress, Physiological / Q000502:physiology*
keywords: Biomechanics; Gait analysis; Knee; Running; Running shoes