title: Postural recovery following voluntary arm movement is impaired in people with chronic low back pain.
abstract: METHODS
  Recovery of postural equilibrium following bilateral voluntary arm movement was evaluated using a case-control study, with 13 subjects with chronic LBP and 13 age- and gendermatched control subjects.
  
  
  OBJECTIVE
  To evaluate control of the centre-of-pressure (COP), as a marker of the quality of control of postural equilibrium associated with voluntary arm movements, in people with and without LBP. Summary of background data. When healthy individuals perform rapid voluntary arm movements, small spinal movements (preparatory movement) opposite to the direction of the reactive moments precede voluntary arm movements. Evaluation of trunk movement in people with LBP suggests that this strategy is used infrequently in this population and is associated with an increased spinal displacement following arm flexion. As the preparatory spinal movement was also thought to be an anticipatory mechanism limiting postural perturbation caused by arm movements, we hypothesized that LBP subjects would have compromised control of postural equilibrium following arm flexion.
  
  
  METHODS
  Subjects performed bilateral voluntary rapid arm flexion while standing on support surface of different dimensions with eyes opened or closed.
  
  
  RESULTS
  Results indicated that people with LBP consistently took longer to recover postural equilibrium and made more postural adjustments in different stance conditions. However, there was no increase in the excursion of the COP during the recovery period in the LBP group.
  
  
  CONCLUSIONS
  These data suggest that while COP is tightly controlled during postural recovery, the finetuning of the control of postural equilibrium is compromised in people with LBP. Postural control dysfunctions should be considered in the management of chronic low back pain.
authors.affiliation: NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health and Division of Physiotherapy, The University of Queensland, Brisbane, Qld, 4072, Australia; Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong.
authors.forename: Nicola W
authors.initials: NW
authors.lastname: Mok
authors.forename: Sandra G
authors.initials: SG
authors.lastname: Brauer
authors.forename: Paul W
authors.initials: PW
authors.lastname: Hodges
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000886:Anthropometry; D001132:Arm / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D002908:Chronic Disease; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D020127:Recovery of Function; D012720:Severity of Illness Index; D012782:Shoulder / Q000503:physiopathology*; D012984:Software; D018709:Statistics, Nonparametric; D013499:Surface Properties; D011795:Surveys and Questionnaires