title: Spine loading in patients with low back pain during asymmetric lifting exertions.
abstract: BACKGROUND
  Recurrent low back pain (LBP) is a common and costly problem that might be related to increased spine loads in those with LBP. However, we know little about how the spine is loaded when those with LBP perform lifting exertions.
  
  
  OBJECTIVE
  Document spine loading patterns of patients with LBP performing symmetric and asymmetric lifting exertions compared with asymptomatic individuals performing the same tasks.
  
  
  METHODS
  Spine loadings during lifting exertions that varied in asymmetric origin as well as horizontal and vertical distance from the spine were compared between asymptomatic subjects and patients with LBP.
  
  
  METHODS
  Sixty-two patients with LBP and 61 asymptomatic individuals performed a variety of lifting exertions that varied in lift origin horizontal and vertical position (region), lift asymmetry position and weight lifted. An electromyography-assisted model was used to evaluate spine loading in each subject during the lifting exertions. Differences in spine loading between the LBP and asymptomatic subjects were noted as a function of the experimental variables.
  
  
  RESULTS
  Patients with LBP experienced greater spine compression and shear forces when performing lifting tasks compared with asymptomatic individuals. The least taxing conditions resulted in some of the greatest differences between LBP and asymptomatic individuals.
  
  
  CONCLUSIONS
  Greater levels of antagonistic muscle coactivation resulted in increases in spine loading for patients with LBP. Specific lifting conditions that tend to exacerbate loading can be identified by means of physical workplace requirements. These findings may impact acceptable return-to-work conditions for those with LBP.
authors.affiliation: Biodynamics Laboratory, The Ohio State University, 210 Baker Systems Engineering, 1971 Neil Avenue, Columbus, OH 43210, USA. marras.1@osu.edu
authors.forename: William S
authors.initials: WS
authors.lastname: Marras
authors.forename: Sue A
authors.initials: SA
authors.lastname: Ferguson
authors.forename: Deborah
authors.initials: D
authors.lastname: Burr
authors.forename: Kermit G
authors.initials: KG
authors.lastname: Davis
authors.forename: Purnendu
authors.initials: P
authors.lastname: Gupta
mesh_terms: D000328:Adult; D019245:Compressive Strength / Q000502:physiology; D004576:Electromyography; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D013131:Spine / Q000503:physiopathology*; D014891:Weight Lifting; D016474:Weight-Bearing