title: A systematic review of randomized controlled trials on exercise parameters in the treatment of patellofemoral pain: what works?
abstract: OBJECTIVE
  There is research evidence which supports the effectiveness of exercise in reducing pain and increasing function in patients with patellofemoral pain syndrome. However, what is unclear are the parameters underpinning this intervention. This has led to uncertainty when operationalizing exercises for patients with patellofemoral pain syndrome in clinical practice. The aim of this review was to evaluate the parameters of exercise programs reported in primary research, to provide clinicians with evidence-based recommendations for exercise prescription for patellofemoral pain.
  
  
  METHODS
  A systematic review of randomized controlled trials was undertaken. Only trials that identified exercise to be effective in treating patellofemoral pain were included. Appropriate databases and reference lists were searched using established keywords. Data relating to common exercise parameters such as the type of exercise, length, and frequency of intervention, intensity, repetitions, sets, and specific technique were extracted, along with details of co-interventions that may have been used.
  
  
  RESULTS
  A total of ten randomized controlled trials were included in this review and from these trials 14 interventions arms were evaluated. All 14 interventions focused on active exercises, all but two of which also included a passive stretching component. The current body of evidence demonstrates positive results with exercise interventions such as knee extension, squats, stationary cycling, static quadriceps, active straight leg raise, leg press, and step-up and down exercises for patients with patellofemoral pain syndrome. A progressive regime of daily exercises of two to four sets of ten or more repetitions over an intervention period of 6 weeks or more, combined with exercises to address flexibility of the lower limb musculature was commonly used.
  
  
  CONCLUSIONS
  Currently, the primary research on this topic supports the use of closed kinetic chain, strengthening exercises for musculature of the lower limb, combined with flexibility options. The current evidence base supports a prescription of daily exercises of two-four sets of ten or more repetitions over a period of 6 weeks or more.
authors.affiliation: International Centre for Allied Health Evidence (iCAHE), City East Campus, University of South Australia, Adelaide, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Harvie
authors.forename: Timothy
authors.initials: T
authors.lastname: O'Leary
authors.forename: Saravana
authors.initials: S
authors.lastname: Kumar