title: Effect of head and limb orientation on trunk muscle activation during abdominal hollowing in chronic low back pain.
abstract: BACKGROUND
  Individuals with chronic low back pain (CLBP) have altered activations patterns of the anterior trunk musculature when performing the abdominal hollowing manœuvre (attempt to pull umbilicus inward and upward towards the spine). There is a subgroup of individuals with CLBP who have high neurocognitive and sensory motor deficits with associated primitive reflexes (PR). The objective of the study was to determine if orienting the head and extremities to positions, which mimic PR patterns would alter anterior trunk musculature activation during the hollowing manoeuvre.
  
  
  METHODS
  This study compared surface electromyography (EMG) of bilateral rectus abdominis (RA), external oblique (EO), and internal obliques (IO) of 11 individuals with CLBP and evident PR to 9 healthy controls during the hollowing manoeuvre in seven positions of the upper quarter.
  
  
  RESULTS
  Using magnitude based inferences it was likely (>75%) that controls had a higher ratio of left IO:RA activation with supine (cervical neutral), asymmetrical tonic neck reflex (ATNR) left and right, right cervical rotation and cervical extension positions. A higher ratio of right IO:RA was detected in the cervical neutral and ATNR left position for the control group. The CLBP group were more likely to show higher activation of the left RA in the cervical neutral, ATNR left and right, right cervical rotation and cervical flexion positions as well as in the cervical neutral and cervical flexion position for the right RA.
  
  
  CONCLUSIONS
  Individuals with CLBP and PR manifested altered activation patterns during the hollowing maneuver compared to healthy controls and that altering cervical and upper extremity position can diminish the group differences. Altered cervical and limb positions can change the activation levels of the IO and EO in both groups.
authors.forename: Kevin
authors.initials: K
authors.lastname: Parfrey
authors.forename: Sean G T
authors.initials: SG
authors.lastname: Gibbons
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Drinkwater
authors.affiliation: School of Human Kinetics and Recreation, Memorial University of Newfoundland, St, John's, Newfoundland, Canada. dbehm@mun.ca.
authors.forename: David G
authors.initials: DG
authors.lastname: Behm
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D059350:Chronic Pain / Q000175:diagnosis / Q000503:physiopathology*; D004185:Disability Evaluation; D004576:Electromyography; D005081:Exercise Therapy; D005260:Female; D019416:Head Movements; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009119:Muscle Contraction; D004856:Postural Balance; D011187:Posture; D017568:Rectus Abdominis / Q000294:innervation / Q000503:physiopathology*; D012018:Reflex; D011795:Surveys and Questionnaires; D016896:Treatment Outcome