title: Effect of recurrent low back pain history on volitional pre-emptive abdominal activation during a loaded functional reach activity.
abstract: METHODS
  A 2 (group) × 2 (abdominal contraction) × 2 (reach activity) crossover mixed design with repeated measures for contraction and activity examined the effects of a loaded (4.6 kg) forward-reach activity and abdominal drawing-in maneuver (ADIM) on transversus abdominis (TrA) contraction in subjects with nonspecific low back pain (NSLBP) history versus controls.
  
  
  OBJECTIVE
  We measured TrA contraction during a loaded forward-reach activity while using the ADIM and examined if a NSLBP history affects TrA activity.
  
  
  BACKGROUND
  The ADIM supports trunk stability during function. Clinicians incorporate ADIM during patients' functional tasks. Pain-free individuals can sustain ADIM during function, such as forward-reach. However, this has not been tested in those with a NSLBP history.
  
  
  METHODS
  Eighteen normal subjects and 18 subjects with a history of NSLBP participated. A blinded investigator recorded M-mode ultrasound imaging measurements of TrA thickness (mm) during 4 conditions as follows: (1) quiet standing without ADIM; (2) quiet standing with ADIM; (3) loaded forward-reach without ADIM; and (4) loaded forward-reach with ADIM.
  
  
  RESULTS
  A mixed analysis of variance demonstrated a significant main effect for group (F [1, 34] = 5.404, P = 0.026; ), where TrA thickness was greater for NSLBP history (7.41 + 2.34 mm) versus controls (5.9 + 2.46 mm). A significant main effect was observed for abdominal contraction (F [1, 34] = 49.57, P < 0.0001; ), where TrA thickness was greater during ADIM (7.47 + 2.7 mm) versus without ADIM (5.84, 1.92 m). A significant main effect was observed for forward-reach activity (F [1, 34] = 12.79, P = 0.001; ), where TrA thickness was greater during a loaded forward-reach (7.04 + 2.6 mm) versus quiet standing (6.2 + 2.4 mm). There were no significant interactions.
  
  
  CONCLUSIONS
  Individuals can use a volitional pre-emptive ADIM for trunk protection during loaded forward-reach, potentially reducing injury risk. A NSLBP history increases TrA activation during ADIM, suggesting an enhanced protective role.
  
  
  METHODS
  2.
authors.affiliation: *Center for Rehabilitation Research, SAHS, Texas Tech University Health Sciences Center, Lubbock, TX; and †Doctor of Physical Therapy Program, Campbell University, Buies Creek, NC.
authors.forename: Vittal R
authors.initials: VR
authors.lastname: Nagar
authors.forename: Troy L
authors.initials: TL
authors.lastname: Hooper
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Dedrick
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Brismée
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sizer
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D011187:Posture / Q000502:physiology; D055502:Secondary Prevention; D016037:Single-Blind Method; D054928:Validation Studies as Topic; D014836:Volition / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult