title: Plinth padding and measures of posteroanterior lumbar stiffness.
abstract: OBJECTIVE
  To investigate whether measurement of posteroanterior (PA) lumbar stiffness is affected by the presence of padding on the testing plinth.
  
  
  METHODS
  Within a repeated-measures design, measurements were made of lumbar PA stiffness in subjects without low back pain on both a rigid and a padded plinth surface.
  
  
  METHODS
  Nineteen subjects with no history of any low back pain requiring treatment over the preceding 12 months participated in this study.
  
  
  METHODS
  PA stiffness was measured at L3 on two occasions under two different conditions. The first condition involved measurement of lumbar stiffness on a rigid plinth surface; the second involved measurement on a padded plinth surface. A reliable mechanical device was used to obtain the PA stiffness measures.
  
  
  RESULTS
  Mean lumbar PA stiffness values obtained when testing on a padded plinth were 2.86 N/mm less than those values obtained when testing the same lumbar spines on a rigid plinth. A paired t test showed a significant difference between the PA stiffness measures at L3 obtained on the padded plinth and those obtained on the rigid plinth (t = 6.66, df = 18, p < or = .0001).
  
  
  CONCLUSIONS
  These findings suggest that to improve the reliability of lumbar PA stiffness assessment, testing should be performed under the same plinth surface conditions.
authors.affiliation: School of Physiotherapy, Faculty of Health Sciences, University of Sydney, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Latimer
authors.forename: M
authors.initials: M
authors.lastname: Holland
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.forename: R
authors.initials: R
authors.lastname: Adams
mesh_terms: D000328:Adult; D002684:Chiropractic / Q000379:methods*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis*; D008297:Male