title: Trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during a single-leg squat in males and females with and without patellofemoral pain syndrome.
abstract: METHODS
  Controlled laboratory study using a cross-sectional design.
  
  
  OBJECTIVE
  To determine whether there are any differences between the sexes in trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during the performance of a single-leg squat in individuals with patellofemoral pain syndrome (PFPS) and control participants.
  
  
  BACKGROUND
  Though there is a greater incidence of PFPS in females, PFPS is also quite common in males. Trunk kinematics may affect hip and knee function; however, there is a lack of studies of the influence of the trunk in individuals with PFPS.
  
  
  METHODS
  Eighty subjects were distributed into 4 groups: females with PFPS, female controls, males with PFPS, and male controls. Trunk, pelvis, hip, and knee kinematics and gluteal muscle activation were evaluated during a single-leg squat. Hip abduction and external rotation eccentric strength was measured on an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFPS status).
  
  
  RESULTS
  Compared to controls, subjects with PFPS had greater ipsilateral trunk lean (mean ± SD, 9.3° ± 5.3° versus 6.7° ± 3.0°; P = .012), contralateral pelvic drop (10.3° ± 4.7° versus 7.4° ± 3.8°; P = .003), hip adduction (14.8° ± 7.8° versus 10.8° ± 5.6°; P<.0001), and knee abduction (9.2° ± 5.0° versus 5.8° ± 3.4°; P<.0001) when performing a single-leg squat. Subjects with PFPS also had 18% less hip abduction and 17% less hip external rotation strength. Compared to female controls, females with PFPS had more hip internal rotation (P<.05) and less muscle activation of the gluteus medius (P = .017) during the single-leg squat.
  
  
  CONCLUSIONS
  Despite many similarities in findings for males and females with PFPS, there may be specific sex differences that warrant consideration in future studies and when clinically evaluating and treating females with PFPS.
authors.affiliation: Federal University of São Carlos, São Carlos, SP, Brazil. theresa.nakagawa@yahoo.com.br
authors.forename: Theresa H
authors.initials: TH
authors.lastname: Nakagawa
authors.forename: Erika T U
authors.initials: ET
authors.lastname: Moriya
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Maciel
authors.forename: Fábio V
authors.initials: FV
authors.lastname: Serrão
mesh_terms: D000293:Adolescent; D000328:Adult; D002081:Buttocks / Q000502:physiology*; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D004576:Electromyography / Q000295:instrumentation; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007717:Knee / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D010329:Patella / Q000502:physiology; D046788:Patellofemoral Pain Syndrome / Q000453:epidemiology / Q000473:pathology*; D010388:Pelvis / Q000502:physiology*; D012737:Sex Factors; D019415:Torque; D014481:United States / Q000453:epidemiology; D014891:Weight Lifting / Q000502:physiology; D055815:Young Adult