title: Evaluation of a new device for measuring responses to posteroanterior forces in a patient population, Part 1: Reliability testing.
abstract: OBJECTIVE
  This study determined the test-retest reliability of measurements of responses to posteroanterior (PA) forces made using a recently developed instrument.
  
  
  METHODS
  Twenty-two subjects with nonspecific low back pain participated.
  
  
  METHODS
  The length of the low- stiffness or "toe" region and the slope of the linear portion of the force-displacement curve were measured on two occasions. Reliability of repeated measurements was evaluated by intraclass correlation coefficients and percentage-of-agreement scores. The presence of a systematic change in the response to PA forces was evaluated by a paired-samples t test.
  
  
  RESULTS
  High reliability coefficients were obtained for both indices of the response to PA forces. The t test revealed no systematic change with repeated testing.
  
  
  CONCLUSIONS
  The new device provides highly reliable measurement of the lumbar PA force-displacement relationship and may prove useful in evaluating theories that have suggested a relationship between spinal symptoms and abnormal PA stiffness.
authors.affiliation: School of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Lidcombe, New South Wales, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Latimer
authors.forename: M M
authors.initials: MM
authors.lastname: Goodsel
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.forename: C G
authors.initials: CG
authors.lastname: Maher
authors.forename: B N
authors.initials: BN
authors.lastname: Wilkinson
authors.forename: C C
authors.initials: CC
authors.lastname: Moran
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D026741:Physical Therapy Modalities / Q000295:instrumentation*; D015203:Reproducibility of Results