title: Movement system impairment-based categories for low back pain: stage 1 validation.
abstract: METHODS
  Cross-sectional study of patients with mechanical low back pain (MLBP).
  
  
  OBJECTIVE
  To test the construct validity of 3 categories of a movement system impairment-based classification proposed for use with patients with MLBP.
  
  
  BACKGROUND
  A pathoanatomic basis for directing treatment has not proven useful in a wide variety of patients with MLBP. In addition, there is a paucity of data describing the movement system impairments that characterize many of the pathoanatomically based MLBP diagnoses. Because of the mechanical nature of MLBP, a system based on groups of signs and symptoms relevant to conservative management needs to be developed.
  
  
  METHODS
  A movement system impairment-based classification was proposed that defined 5 categories of MLBP based on the findings from a standardized examination. Using the examination, 5 physical therapists examined a total of 188 patients with MLBP. A principal components analysis with an oblique rotation was conducted. Eigenvalues were plotted and a scree test was used to determine the number of factors to retain. A split-sample cross-validation procedure was conducted to verify the factor structure.
  
  
  RESULTS
  Three factors were identified in both samples: 2 factors related to symptoms with lumbar rotation and lumbar extension alignments or movements, and 1 factor related to signs of lumbar rotation with different alignments and movements.
  
  
  CONCLUSIONS
  Our results provide support for 3 factors related to 3 of the 5 proposed categories: lumbar rotation with extension, lumbar rotation, and lumbar extension. The existence of these 3 factors provides preliminary evidence for specific clusters of tests of alignment and movement impairments that could be used in classifying patients with MLBP into movement-system-related categories.
authors.affiliation: Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO 63110, USA. vandillenl@msnotes.wustl.edu
authors.forename: Linda R
authors.initials: LR
authors.lastname: Van Dillen
authors.forename: Shirley A
authors.initials: SA
authors.lastname: Sahrmann
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Norton
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Caldwell
authors.forename: Mary Kate
authors.initials: MK
authors.lastname: McDonnell
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Bloom
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000145:classification* / Q000503:physiopathology / Q000534:rehabilitation; D008161:Lumbosacral Region / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D010808:Physical Examination / Q000379:methods*; D011187:Posture / Q000502:physiology; D015203:Reproducibility of Results; D012399:Rotation