title: Effectiveness of hip muscle strengthening in patellofemoral pain syndrome patients: a systematic review.
abstract: BACKGROUND
  Patellofemoral pain syndrome (PFPS) is characterized by anterior knee pain, which may limit the performance of functional activities. The influence of hip joint motion on the development of this syndrome has already been documented in the literature. In this regard, studies have investigated the effectiveness of hip muscle strengthening in patients with PFPS.
  
  
  OBJECTIVE
  The aims of this systematic review were (1) to summarize the literature related to the effects of hip muscle strengthening on pain intensity, muscle strength, and function in individuals with PFPS and (2) to evaluate the methodological quality of the selected studies.
  
  
  METHODS
  A search for randomized controlled clinical trials was conducted using the following databases: Google Scholar, MEDLINE, PEDro, LILACS, and SciELO. The selected studies had to distinguish the effects of hip muscle strengthening in a group of patients with PFPS, as compared to non-intervention or other kinds of intervention, and had to investigate the following outcomes: pain, muscle strength, and function. The methodological quality of the selected studies was analyzed by means of the PEDro scale.
  
  
  RESULTS
  Seven studies were selected. These studies demonstrated that hip muscle strengthening was effective in reducing pain. However, the studies disagreed regarding the treatments' ability to improve muscle strength. Improvement in functional capabilities after hip muscle strengthening was found in five studies.
  
  
  CONCLUSIONS
  Hip muscle strengthening is effective in reducing the intensity of pain and improving functional capabilities in patients with PFPS, despite the lack of evidence for its ability to increase muscle strength.
authors.affiliation: Departamento de Fisioterapia, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Thiago R T
authors.initials: TR
authors.lastname: Santos
authors.affiliation: Departamento de Fisioterapia, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Bárbara A
authors.initials: BA
authors.lastname: Oliveira
authors.affiliation: Departamento de Fisioterapia, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Ocarino
authors.affiliation: Department of Physical Therapy and Athletic Training, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts, United States.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Holt
authors.affiliation: Departamento de Fisioterapia, Escola de Educação Física, Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Sérgio T
authors.initials: ST
authors.lastname: Fonseca
mesh_terms: D005081:Exercise Therapy; D006615:Hip; D006801:Humans; D053580:Muscle Strength; D046788:Patellofemoral Pain Syndrome / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome