title: The relationship between quadriceps strength and joint position sense, functional outcome and painful activities in patellofemoral pain syndrome.
abstract: OBJECTIVE
  The aim of this study was to investigate how strongly the concentric and eccentric quadriceps strengths were correlated with the joint position sense, functional outcomes and painful activities in patients with patellofemoral pain syndrome (PFPS).
  
  
  METHODS
  The study included forty-six women diagnosed with unilateral PFPS. Eccentric and concentric quadriceps strengths were recorded at 60 and 180°/s. Active knee joint position sense (JPS) was measured at 20° and 60° of flexion. Functional levels were determined by using Kujala patellofemoral scores. Pain levels during stair descending and ascending, squatting and prolonged sitting were measured using 0-10 cm visual analogue scale. The relationship of isokinetic quadriceps strength with JPS results, Kujala score and pain levels were evaluated using Spearman's correlation coefficient test.
  
  
  RESULTS
  Eccentric and concentric quadriceps strengths were significantly lower on involved side than uninvolved side. JPS results were poorer on the painful knee when compared to uninvolved side. While eccentric strength correlated with both JPS target angles, concentric strength was correlated only with 20°. Both eccentric and concentric strengths were significantly correlated with Kujala scores and pain levels.
  
  
  CONCLUSIONS
  Quadriceps eccentric strength was correlated more to joint position sense than concentric strength. Both eccentric and concentric quadriceps strength related to pain and functional level in PFPS patients.
authors: Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Hacettepe University, 06100, Ankara, Turkey. hande.guney@hacettepe.edu.tr.
authors: Hande
authors: H
authors: Guney
authors: Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Hacettepe University, 06100, Ankara, Turkey.
authors: Inci
authors: I
authors: Yuksel
authors: Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Biruni University, 34010, Istanbul, Turkey.
authors: Defne
authors: D
authors: Kaya
authors: Department of Orthopaedics and Traumatology, Faculty of Medicine, Hacettepe University, 06100, Ankara, Turkey.
authors: Mahmut Nedim
authors: MN
authors: Doral
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D011434:Proprioception / Q000502:physiology*; D011446:Prospective Studies; D052097:Quadriceps Muscle / Q000503:physiopathology*; D016059:Range of Motion, Articular
keywords: Eccentric strength; Function; Joint position sense; Pain; Patellofemoral pain syndrome