title: Reliability of rehabilitative ultrasound imaging of the transversus abdominis and lumbar multifidus muscles.
abstract: OBJECTIVE
  To evaluate the intraexaminer and interexaminer reliability of rehabilitative ultrasound imaging (RUSI) in obtaining thickness measurements of the transversus abdominis (TrA) and lumbar multifidus muscles at rest and during contractions.
  
  
  METHODS
  Single-group repeated-measures reliability study.
  
  
  METHODS
  University and orthopedic physical therapy clinic.
  
  
  METHODS
  A volunteer sample of adults (N=30) with current nonspecific low back pain (LBP) was examined by 2 clinicians with minimal RUSI experience.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Thickness measurements of the TrA and lumbar multifidus muscles at rest and during contractions were obtained by using RUSI during 2 sessions 1 to 3 days apart. Percent thickness change was calculated as thickness(contracted)-thickness(rest)/thickness(rest). Intraclass correlation coefficients (ICC) were used to estimate reliability.
  
  
  RESULTS
  By using the mean of 2 measures, intraexaminer reliability point estimates (ICC(3,2)) ranged from 0.96 to 0.99 for same-day comparisons and from 0.87 to 0.98 for between-day comparisons. Interexaminer reliability estimates (ICC(2,2)) ranged from 0.88 to 0.94 for within-day comparisons and from 0.80 to 0.92 for between-day comparisons. Reliability estimates comparing measurements by the 2 examiners of the same image (ICC(2,2)) ranged from 0.96 to 0.98. Reliability estimates were lower for percent thickness change measures than the corresponding single thickness measures for all conditions.
  
  
  CONCLUSIONS
  RUSI thickness measurements of the TrA and lumbar multifidus muscles in patients with LBP, when based on the mean of 2 measures, are highly reliable when taken by a single examiner and adequately reliable when taken by different examiners.
authors.affiliation: College of Health, University of Utah, Salt Lake City, UT, USA. shanekoppenhaver@mac.com
authors.forename: Shane L
authors.initials: SL
authors.lastname: Koppenhaver
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Hebert
authors.forename: Julie M
authors.initials: JM
authors.lastname: Fritz
authors.forename: Eric C
authors.initials: EC
authors.lastname: Parent
authors.forename: Deydre S
authors.initials: DS
authors.lastname: Teyhen
authors.forename: John S
authors.initials: JS
authors.lastname: Magel
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging* / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D015588:Observer Variation; D015203:Reproducibility of Results; D012146:Rest; D014463:Ultrasonography