title: Measurement of the number of lumbar spinal movements in the sagittal plane in a 24-hour period.
abstract: OBJECTIVE
  Little is known about the number of spinal movements in the sagittal plane in daily life, mainly due to the lack of adequate techniques to assess these movements. Our aim was to measure these movements in asymptomatic volunteers.
  
  
  METHODS
  Two sensor strips based on strain gauge technology (Epionics SPINE system) were fixed on the skin surface of the back parallel to the spine on a total of 208 volunteers without back pain. First, the lordosis angle was determined during relaxed standing. The volunteers were then released to daily life. The increases and decreases in the back lumbar lordosis angle over a period of 24 h were determined and classified into 5° increments. Changes in the lordosis angle greater than 5° were considered.
  
  
  RESULTS
  The median number of spinal movements performed within 24 h was approximately 4,400. Of these movements, 66 % were between 5° and 10°. The proportions of higher-magnitude lordosis angle changes were much lower (e.g., 3 % for the 20-25° movement bin). Surprisingly, the median total number of movements was significantly higher (29 %) in women than in men. Large inter-individual differences were observed in the number of movements performed. The volunteers spent a median of 4.9 h with the lumbar spine flexed between 20° and 30° and only 24 min with the spine extended relative to the reference standing position. A median of 50 movements reached or exceeded full-flexion angle and zero movements full-extension angle.
  
  
  CONCLUSIONS
  These data illustrate the predominantly small range of movement of the spine during daily activities and the small amount of time spent in extension. These unique data strongly contribute to the understanding of patients' everyday behavior, which might affect the development and testing of spinal implants and the evaluation of surgical and nonsurgical treatments.
authors.affiliation: Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany, antonius.rohlmann@charite.de.
authors.forename: Antonius
authors.initials: A
authors.lastname: Rohlmann
authors.forename: Tobias
authors.initials: T
authors.lastname: Consmüller
authors.forename: Marcel
authors.initials: M
authors.lastname: Dreischarf
authors.forename: Maxim
authors.initials: M
authors.lastname: Bashkuev
authors.forename: Alexander
authors.initials: A
authors.lastname: Disch
authors.forename: Esther
authors.initials: E
authors.lastname: Pries
authors.forename: Georg N
authors.initials: GN
authors.lastname: Duda
authors.forename: Hendrik
authors.initials: H
authors.lastname: Schmidt
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D008141:Lordosis / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D009068:Movement / Q000502:physiology*; D012737:Sex Factors; D055815:Young Adult