title: Neuromuscular response amplitude to mechanical stimulation using large-array surface electromyography in participants with and without chronic low back pain.
abstract: OBJECTIVE
  The present study aimed to compare the neuromuscular response under various mechanical stimulations of the lumbar spine in participants with and without chronic low back pain (cLBP).
  
  
  METHODS
  Four mechanical stimulations, characterized by forces ranging from 75 to 225N, were delivered using a servo-controlled linear actuator motor to the L3 spinous process of 25 healthy participants and 26 participants with cLBP. Lumbar neuromuscular responses were recorded using 64-electrodes large surface electromyography arrays. Between-group differences in the dose-response relationship (neuromuscular response amplitude according to each force level) were assessed using mixed model ANOVAs.
  
  
  RESULTS
  No differences between groups were shown (all p values>.05). A significant linear relationship was observed between forces and neuromuscular response amplitudes (p<.001) indicating an increase in response amplitudes with increasing stimulation force. Responses were observed throughout the lumbar region with highest response amplitudes in the vicinity of the contacted vertebra.
  
  
  CONCLUSIONS
  The neuromuscular response amplitude triggered by localized lumbar mechanical stimulations does not differ between participants with and without cLBP. Moreover, even though stimulations were delivered at specific spinal segment, a neuromuscular response, although rapidly decreasing, was observed in areas distant from the contact site.
authors.affiliation: Département d'anatomie, Université du Québec à Trois-Rivières, 3351 boul. des Forges, Trois-Rivières, Québec G9A 5H7, Canada. Electronic address: Isabelle.Page1@uqtr.ca.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pagé
authors.affiliation: Département des sciences de l'activité physique, Université du Québec à Trois-Rivières, 3351 boul. des Forges, Trois-Rivières, Québec G9A 5H7, Canada. Electronic address: Francois.Nougarou@gmail.com.
authors.forename: François
authors.initials: F
authors.lastname: Nougarou
authors.affiliation: Département des sciences de l'activité physique, Université du Québec à Trois-Rivières, 3351 boul. des Forges, Trois-Rivières, Québec G9A 5H7, Canada. Electronic address: Martin.Descarreaux@uqtr.ca.
authors.forename: Martin
authors.initials: M
authors.lastname: Descarreaux
mesh_terms: D000328:Adult; D064131:Back Muscles / Q000502:physiology*; D059350:Chronic Pain / Q000175:diagnosis* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology; D008159:Lumbar Vertebrae; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation / Q000295:instrumentation / Q000379:methods
keywords: Dose–response relationship; Electromyography; Neurophysiology; Spinal manipulation; Spine; Stretch reflex