title: Clinimetric analysis of pressure biofeedback and transversus abdominis function in individuals with stabilization classification low back pain.
abstract: METHODS
  Descriptive laboratory study.
  
  
  OBJECTIVE
  To determine if a proposed clinical test (pressure biofeedback) could detect changes in transversus abdominis (TrA) muscle thickness during an abdominal drawing-in maneuver.
  
  
  BACKGROUND
  Pressure biofeedback may be used to assess abdominal muscle function and TrA activation during an abdominal drawing-in maneuver but has not been validated.
  
  
  METHODS
  Forty-nine individuals (18 men, 31 women) with low back pain who met stabilization classification criteria underwent ultrasound imaging to quantify changes in TrA muscle thickness while a pressure transducer was used to measure pelvic and spine position during an abdominal drawing-in maneuver. A paired t test was used to compare differences in TrA activation ratios between groups (able or unable to maintain pressure of 40 ± 5 mmHg). The groups were further dichotomized based on TrA activation ratio (high, greater than 1.5; low, less than 1.5). Sensitivity, specificity, and likelihood ratios were calculated.
  
  
  RESULTS
  There was not a significant difference (P = .57) in TrA activation ratios (able to maintain pressure, 1.59 ± 0.28; unable to maintain pressure, 1.54 ± 0.24) between groups. The pressure biofeedback test had low sensitivity of 0.22 (95% confidence interval [CI]: 0.10, 0.42) but moderate specificity of 0.77 (95% CI: 0.58, 0.89), a positive likelihood ratio of 0.94 (95% CI: 0.33, 2.68), and a negative likelihood ratio of 1.02 (95% CI: 0.75, 1.38).
  
  
  CONCLUSIONS
  Successful completion on pressure biofeedback does not indicate high TrA activation. Unsuccessful completion on pressure biofeedback may be more indicative of low TrA activation, but the correlation and likelihood coefficients indicate that the pressure test is likely of minimal value to detect TrA activation. This study was registered with ClinicalTrials.gov (NCT01015846).J Orthop Sports Phys Ther 2013;43(3):184-193. Epub 16 November 2012. doi:10.2519/jospt.2013.4397.
authors.affiliation: School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA. 　Grooms.69@osu.edu
authors.forename: Dustin R
authors.initials: DR
authors.lastname: Grooms
authors.forename: Terry L
authors.initials: TL
authors.lastname: Grindstaff
authors.forename: Theodore
authors.initials: T
authors.lastname: Croy
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D001676:Biofeedback, Psychology / Q000379:methods*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000145:classification / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D014463:Ultrasonography; D055815:Young Adult