title: A biomechanical comparison of lifting techniques between subjects with and without chronic low back pain during freestyle lifting and lowering tasks.
abstract: OBJECTIVE
  To evaluate if chronic low back pain patients perform manual material handling tasks differently from control subjects.
  
  
  METHODS
  Comparative study using a repeated measures design.
  
  
  BACKGROUND
  No study evaluated the lifting technique of back pain patients relative to control subjects during free style lifting and lowering tasks. Previous findings suggest that lowering would be more hazardous than lifting to the low back. It would be interesting to evaluate if chronic low back pain patients behave differently than controls when lifting and lowering.
  
  
  METHODS
  Thirty-three male subjects (18 controls, 15 suffering from non-specific chronic low back pain) participated. A 12-kg box was lifted (freestyle) from the floor to the hips (1) in front (symmetric task) or (2) to a shelf located at 90 degree on the right (asymmetric task) and was lowered back to the floor. A 3D biomechanical analysis involving the assessment of L5/S1 loading, posture of segments, inertial parameters, and EMG was performed.
  
  
  RESULTS
  There was no difference between the groups for postural (trunk and lower limb angles), inertial (trunk velocity and acceleration), and L5/S1 loading (moments and compression) variables. The patients showed abnormally low left lumbar erector spinae (symmetric task, lowering) or high left thoracic erector spinae (all tasks) EMG activation. Significant Group x Action (lifting vs. lowering) interactions were also observed for some inertial and L5/S1 loading variables suggesting that the biomechanical differences detected between lifting and lowering may have a differential influence on the technique used by back pain patients and control subjects.
  
  
  CONCLUSIONS
  The gross lifting technique of back pain patients was unaltered relative to controls but the activation of paraspinal muscles differed, suggesting that a more detailed biomechanical analysis, such as the use of EMG driven models, might be required to reveal lumbar impairments during lifting.
  
  
  CONCLUSIONS
  To evaluate if chronic low back pain patients use naturally different lifting techniques to prevent pain exacerbation and damaged lumbar tissue overloading.
authors.affiliation: Centre de Recherche Clinique en Readaptation au Travail, Charles LeMoyne Hospital (PREVICAP), University of Sherbrooke, Bureau 101, 1111 St. Charles Ouest, J4K 5G4, Longueil, Que., Canada. christian.lariviere@courrier.usherb.ca
authors.forename: Christian
authors.initials: C
authors.lastname: Larivière
authors.forename: Denis
authors.initials: D
authors.lastname: Gagnon
authors.forename: Patrick
authors.initials: P
authors.lastname: Loisel
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D006801:Humans; D017770:Lifting; D017116:Low Back Pain / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000503:physiopathology; D012447:Sacrum / Q000503:physiopathology; D013647:Task Performance and Analysis