title: A comparison of lumbopelvic motion patterns and erector spinae behavior between asymptomatic subjects and patients with recurrent low back pain during pain-free periods.
abstract: OBJECTIVE
  The purpose of this study was to determine the patterns of lumbopelvic motion and erector spinae (ES) activity during trunk flexion-extension movements and to compare these patterns between patients with recurrent low back pain (LBP) in their pain-free periods and matched asymptomatic subjects.
  
  
  METHODS
  Thirty subjects participated (15 patients with disc herniation and recurrent LBP in their pain-free periods and 15 asymptomatic control subjects). A 3-dimensional videophotogrammetric system and surface electromyography (EMG) were used to record the angular displacements of the lumbar spine and hip in the sagittal plane and the EMG activity of the ES during standardized trunk flexion-extension cycles. Variables were maximum ranges of spine and hip flexion; percentages of maximum lumbar and hip flexion at the start and end of ES relaxation; average percentages of EMG activity during flexion, relaxation, and extension; and flexion-extension ratio of myoelectrical activity.
  
  
  RESULTS
  Recurrent LBP patients during their pain-free period showed significantly greater ES activation both in flexion and extension, with a higher flexion-extension ratio than controls. Maximum ranges of lumbar and hip flexion showed no differences between controls and patients, although patients spent less time with their lumbar spine maximally flexed.
  
  
  CONCLUSIONS
  This study showed that reduced maximum ranges of motion and absence of ES flexion-relaxation phenomenon were not useful to identify LBP patients in the absence of acute pain. However, these patients showed subtle alterations of their lumbopelvic motion and ES activity patterns, which may have important clinical implications.
authors.affiliation: Associate Professor, Department of Anatomy and Human Embryology, Universitat de València, Valencia, Spain. Electronic address: daniel.sanchez@uv.es.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sánchez-Zuriaga
authors.affiliation: Researcher, Research and Development Area, Instituto de Biomecánica de Valencia, Valencia, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: López-Pascual
authors.affiliation: Technological Services Manager, Instituto de Biomecánica de Valencia, Valencia, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Garrido-Jaén
authors.affiliation: Manager, Biomechanical Assessment Unit, Biovalcor, Valencia, Spain.
authors.forename: Maria Amparo
authors.initials: MA
authors.lastname: García-Mas
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D017116:Low Back Pain / Q000175:diagnosis* / Q000628:therapy; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012008:Recurrence; D012016:Reference Values
keywords: Low Back Pain; Lumbar Region; Movement; Muscle Relaxation; Paraspinal Muscles