title: Repositioning accuracy and movement parameters in low back pain subjects and healthy control subjects.
abstract: METHODS
  A control group study with repeated measures.
  
  
  OBJECTIVE
  To compare trunk repositioning parameters in chronic low back pain (LBP) and healthy subjects.
  
  
  BACKGROUND
  Recent evidence suggests that chronic LBP patients exhibit deficits in trunk proprioception and motor control. Trunk repositioning and the various spatio-temporal parameters related to it can be used to evaluate sensori-motor control and movement strategies.
  
  
  METHODS
  Fifteen control subjects and 16 chronic LBP subjects participated in this study. Subjects were required to reproduce different trunk position in flexion (15 degrees, 30 degrees and 60 degrees) and extension (15 degrees). In the learning phase preceding each condition, visual feedback was provided. Following these learning trials, subjects were asked to perform ten consecutive trials without any feedback. Movement time, movement time variability and peak velocity were obtained and a temporal symmetry ratio was calculated. Peak angular position variability and absolute error in peak angular position were also calculated to evaluate spatial accuracy.
  
  
  RESULTS
  Two subgroups of LBP patients were identified. One subgroup of LBP subjects demonstrated longer movement time and smaller peak velocities and symmetry ratios than normal subjects. No group difference was observed for peak angular position variability and absolute error in peak angular position.
  
  
  CONCLUSIONS
  Chronic LBP patients, when given a sufficient learning period, were able to reproduce trunk position with a spatial accuracy similar to control subjects. Some LBP subjects, however, showed modifications of movement time, peak velocity and acceleration parameters. We propose that the presence of persistent chronic pain could induce an alteration or an adaptation in the motor responses of chronic LBP subjects.
authors.affiliation: Département de Chiropratique, Université du Québec à Trois-Rivières, Bureau 3613, 3351 Boulevarde Des Forges C.P. 500, Trois-Rivières, Qc, Canada, G9A5H7. Martin_descarreaux@uqtr.ca
authors.forename: Martin
authors.initials: M
authors.lastname: Descarreaux
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Blouin
authors.forename: Normand
authors.initials: N
authors.lastname: Teasdale
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011434:Proprioception / Q000502:physiology*