title: Altered muscle recruitment during extension from trunk flexion in low back pain developers.
abstract: BACKGROUND
  A functionally induced, transient low back pain model consisting of exposure to prolonged standing has been used to elucidate baseline neuromuscular differences between previously asymptomatic individuals classified as pain developers and non-pain developers based on their pain response during a standing exposure. Previous findings have included differences in frontal plane lumbopelvic control and altered movement strategies that are present prior to pain development. Control strategies during sagittal plane movement have not been previously investigated in this sample. The purpose of this research was to investigate neuromuscular control differences during the extension phase from trunk flexion between pain developers and non-pain developers.
  
  
  METHODS
  Continuous electromyography and kinematic data were collected during standing trunk flexion and extension on 43 participants (22 male) with an age range of 18-33 years, prior to entering into the prolonged standing exposure. Participants were classified as pain developer/non-pain developer by their pain response (≥ 10 mm increase on a 100 mm visual analog scale) during standing. Relative timing and sequencing data between muscle pairs were calculated through cross-correlation analyses, and evaluated by group and gender.
  
  
  RESULTS
  Pain developers demonstrated a 'top-down' muscle recruitment strategy with lumbar extensors activated prior to gluteus maximus, while non-pain developers demonstrated a typical 'bottom-up' muscle recruitment strategy with gluteus maximus activated prior to lumbar extensors.
  
  
  CONCLUSIONS
  Individuals predisposed to low back pain development during standing exhibited altered neuromuscular strategies prior to pain development. These findings may help to characterize biomechanical movement profiles that could be important for early identification of people at risk for low back pain.
authors.affiliation: Regis University School of Physical Therapy, 3333 Regis Blvd, G4, Denver, CO 80221, USA. enelsonw@regis.edu
authors.forename: Erika
authors.initials: E
authors.lastname: Nelson-Wong
authors.forename: Brendan
authors.initials: B
authors.lastname: Alex
authors.forename: David
authors.initials: D
authors.lastname: Csepe
authors.forename: Denver
authors.initials: D
authors.lastname: Lancaster
authors.forename: Jack P
authors.initials: JP
authors.lastname: Callaghan
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D006615:Hip / Q000502:physiology; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008161:Lumbosacral Region / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011999:Recruitment, Neurophysiological; D012737:Sex Factors; D055815:Young Adult