title: Loading and recovery behavior of the human lumbar spine under static flexion.
abstract: OBJECTIVE
  In this study, the effect of prolonged forward flexion on the recovery process of the reflexive muscle activity of the lumbar musculature to its original state is studied using human participants.
  
  
  METHODS
  The behavior of the lower back erector spinae muscle during 20 minutes of forward bending and three hours of recovery was evaluated experimentally using electromyography (EMG) and mathematical modeling.
  
  
  METHODS
  Ten healthy males participated in this study. The EMG of erector-spinae muscle from two different lumbar levels was recorded and expressed as normalized integrated EMG (NIEMG).
  
  
  RESULTS
  In general, the average NIEMG values of the erector spinae muscles demonstrated an exponential decrease during the 20-minute loading period. The biexoponential structure, derived from the animal model, did not completely explain the muscle behavior during recovery period. Inclusion of the "intrinsic loading factor" to the biexoponential structure improved the fit of the recovery model to 100%.
  
  
  CONCLUSIONS
  Most of the recovery (almost 50%) of the reflexive activity of erector spinae muscle was observed in the initial 30 minutes; yet by the end of three hours, complete recovery was not observed.
authors.affiliation: Department of Construction Management and Industrial Engineering, Louisiana State University, Baton Rouge, LA 708036409, USA.
authors.forename: Guntulu Selen
authors.initials: GS
authors.lastname: Hatipkarasulu
authors.forename: Fereydoun
authors.initials: F
authors.lastname: Aghazadeh
authors.forename: Ashish D
authors.initials: AD
authors.lastname: Nimbarte
mesh_terms: D000328:Adult; D004576:Electromyography; D006801:Humans; D017116:Low Back Pain; D008159:Lumbar Vertebrae / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*