title: Concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain.
abstract: BACKGROUND
  Individuals suffering from patellofemoral pain have previously been reported to have decreased isometric strength of the hip musculature; however, no researchers have investigated concentric and eccentric torque of the hip musculature in individuals with patellofemoral pain.
  
  
  OBJECTIVE
  To compare concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain.
  
  
  METHODS
  Case control.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Twenty participants with patellofemoral pain (age = 26.8 +/- 4.5 years, height = 171.8 +/- 8.4 cm, mass = 72.4 +/- 16.8 kg) and 20 control participants (age = 25.6 +/- 2.8 years, height = 169.5 +/- 8.9 cm, mass = 70.0 +/- 16.9 kg) were tested. Volunteers with patellofemoral pain met the following criteria: knee pain greater than or equal to 3 cm on a 10-cm visual analog scale, insidious onset of symptoms not related to trauma, pain with palpation of the patellar facets, and knee pain during 2 of the following activities: stair climbing, jumping or running, squatting, kneeling, or prolonged sitting. Control participants were excluded if they had a prior history of patellofemoral pain, knee surgery in the past 2 years, or current lower extremity injury that limited participation in physical activity.
  
  
  METHODS
  Concentric and eccentric torque of the hip musculature was measured on an isokinetic dynamometer. All volunteers performed 5 repetitions of each strength test. Separate multivariate analyses of variance were performed to compare concentric and eccentric torque of the hip extensors, abductors, and external rotators between groups.
  
  
  METHODS
  Average and peak concentric and eccentric torque of the hip extensors, abductors, and external rotators. Torque measures were normalized to the participant's body weight multiplied by height.
  
  
  RESULTS
  The patellofemoral pain group was weaker than the control group for peak eccentric hip abduction torque (F(1,38) = 6.630, P = .014), and average concentric (F(1,38) = 4.156, P = .048) and eccentric (F(1,38) = 4.963, P = .032) hip external rotation torque.
  
  
  CONCLUSIONS
  The patellofemoral pain group displayed weakness in eccentric hip abduction and hip external rotation, which may allow for increased hip adduction and internal rotation during functional movements.
authors.affiliation: Department of Athletic Training and Physical Therapy, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA. m.boling@unf.edu
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Boling
authors.forename: Darin A
authors.initials: DA
authors.lastname: Padua
authors.forename: R
authors.initials: R
authors.lastname: Alexander Creighton
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006615:Hip; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D035002:Lower Extremity; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D046788:Patellofemoral Pain Syndrome / Q000209:etiology / Q000503:physiopathology*; D019415:Torque; D055815:Young Adult