title: The immediate effects of foot orthoses on hip and knee kinematics and muscle activity during a functional step-up task in individuals with patellofemoral pain.
abstract: BACKGROUND
  Evidence shows that anti-pronating foot orthoses improve patellofemoral pain, but there is a paucity of evidence concerning mechanisms. We investigated the immediate effects of prefabricated foot orthoses on (i) hip and knee kinematics; (ii) electromyography variables of vastus medialis oblique, vastus lateralis and gluteus medius during a functional step-up task, and (iii) associated clinical measures.
  
  
  METHODS
  Hip muscle activity and kinematics were measured during a step-up task with and without an anti-pronating foot orthoses, in people (n=20, 9 M, 11 F) with patellofemoral pain. Additionally, we measured knee function, foot posture index, isometric hip abductor and knee extensor strength and weight-bearing ankle dorsiflexion.
  
  
  RESULTS
  Reduced hip adduction (0.82°, P=0.01), knee internal rotation (0.46°, P=0.03), and decreased gluteus medius peak amplitude (0.9mV, P=0.043) were observed after ground contact in the 'with orthoses' condition. With the addition of orthoses, a more pronated foot posture correlated with earlier vastus medialis oblique onset (r=-0.51, P=0.02) whilst higher Kujala scores correlated with earlier gluteus medius onset (r=0.52, P=0.02).
  
  
  CONCLUSIONS
  Although small in magnitude, reductions in hip adduction, knee internal rotation and gluteus medius amplitude observed immediately following orthoses application during a task that commonly aggravates symptoms, offer a potential mechanism for their effectiveness in patellofemoral pain management. Given the potential for cumulative effects of weight bearing repetitions completed with a foot orthoses, for example during repeated stair ascent, the differences are likely to be clinically meaningful.
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, England, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Lack
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, England, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Barton
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, England, United Kingdom.
authors.forename: Roger
authors.initials: R
authors.lastname: Woledge
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, England, United Kingdom.
authors.forename: Markus
authors.initials: M
authors.lastname: Laupheimer
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, England, United Kingdom. Electronic address: d.morrissey@qmul.ac.uk.
authors.forename: Dylan
authors.initials: D
authors.lastname: Morrissey
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002081:Buttocks; D004576:Electromyography; D005260:Female; D005528:Foot / Q000503:physiopathology; D061826:Foot Orthoses; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D009142:Musculoskeletal Physiological Phenomena; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D011187:Posture / Q000502:physiology; D013848:Thigh / Q000503:physiopathology; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Electromyography; Kinematics; Onset times; Orthoses; Patellofemoral pain