title: Physical therapy alters recruitment of the vasti in patellofemoral pain syndrome.
abstract: OBJECTIVE
  To investigate the effect of physical therapy treatment on the timing of electromyographic (EMG) activity of the vasti in individuals with patellofemoral pain syndrome (PFPS).
  
  
  METHODS
  Sixty-five (42 female, 23 male) participants aged 40 yr or less (29.2 +/- 7.8 yr) diagnosed with PFPS. Participants were randomly allocated into physical therapy treatment (McConnell-based) or placebo groups. Treatment programs were standardized and consisted of six-treatment sessions over 6 wk. Vastus medialis oblique (VMO) and vastus lateralis (VL) EMG activity was recorded with surface electrodes during a stair-stepping task and onsets of EMG activity were measured pre- and post-treatment.
  
  
  RESULTS
  Before treatment, the EMG onset of VL occurred before that of VMO in both participant groups. After physical therapy intervention, there was a reduction in symptoms, and this improvement was associated with a significant change in the time of onset of VMO EMG compared with that of VL in both phases of the stair-stepping task. After physical therapy treatment, the onset of VMO preceded VL in the eccentric phase and occurred at the same time in the concentric phase of the stair-stepping task. There was no change in time of EMG onset in the placebo group.
  
  
  CONCLUSIONS
  This study demonstrates that a "McConnell"-based physical therapy treatment regime for PFPS alters the motor control of VMO relative to VL in a functional task and this is associated with a positive clinical outcome.
authors.affiliation: Centre for Sports Medicine Research and Education, School of Physiotherapy, The University of Melbourne, 200 Berkeley St, Carlton, Vic, 3010, Australia. s.cowan@unimelb.edu.au
authors.forename: Sallie M
authors.initials: SM
authors.lastname: Cowan
authors.forename: Kim L
authors.initials: KL
authors.lastname: Bennell
authors.forename: Kay M
authors.initials: KM
authors.lastname: Crossley
authors.forename: Paul W
authors.initials: PW
authors.lastname: Hodges
authors.forename: Jenny
authors.initials: J
authors.lastname: McConnell
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004576:Electromyography; D005081:Exercise Therapy; D005260:Female; D005269:Femur / Q000503:physiopathology*; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000150:complications / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D015588:Observer Variation; D010146:Pain / Q000150:complications / Q000503:physiopathology*; D010147:Pain Measurement; D010329:Patella / Q000503:physiopathology*; D011237:Predictive Value of Tests; D013223:Statistics as Topic; D013577:Syndrome; D013997:Time Factors; D016896:Treatment Outcome