title: Reliability of Ultrasound Imaging Measures of Transverse Abdominis and Lumbar Multifidus in Various Positions.
abstract: OBJECTIVE
  To determine the reliability of measurement of muscle activation via ultrasound imaging measures of the transverse abdominis (TrA) and lumbar multifidus (LM) in tabletop, seated, standing, and walking conditions.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Sixteen healthy participants (age, 20.4 ± 1.8 years; height, 167.7 ± 9.0 cm; mass, 65.1 ± 10.8 kg).
  
  
  METHODS
  None.
  
  
  METHODS
  The activation ratio (AR) of TrA and LM and preferential activation ratio of TrA in tabletop, seated, standing, and walking positions were assessed by the same examiner during 2 ultrasound imaging sessions 24-72 hours apart. Statistical analysis included determination of intraclass correlation coefficients (ICCs) using analysis of variance for each muscle and position between sessions.
  
  
  RESULTS
  Excellent reliability was found in TrA AR between sessions for healthy participants in the tabletop position (ICC3,k = 0.903), and acceptable to excellent reliability was found in seated (ICC3,k = 0.613), standing (ICC3,k = 0.553), and walking (ICC3,k = 0.737) positions. LM AR was fair in the tabletop position for these participants (ICC3,k = 0.264). The preferential activation ratio for healthy participants was substantially reliable in tabletop and seated positions (ICC3,k = 0.668, 0.684) and showed fair reliability for walking (ICC3,k = 0.455).
  
  
  CONCLUSIONS
  Ultrasound imaging is a reliable method of measuring muscle thickness across multiple positions in healthy persons. This measure may be used to compare abdominal muscle thickness across populations or after interventions. LM AR was only found to be reliable in the tabletop position.
authors.affiliation: University of Virginia Exercise and Sport Injury Laboratory, 210 Emmet St South, Charlottesville, VA 22904(∗). Electronic address: lcm5xj@virginia.edu.
authors.forename: L Colby
authors.initials: LC
authors.lastname: Mangum
authors.affiliation: University of Virginia Exercise and Sport Injury Laboratory, 210 Emmet St South, Charlottesville, VA 22904(†).
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sutherlin
authors.affiliation: University of Virginia Exercise and Sport Injury Laboratory, 210 Emmet St South, Charlottesville, VA 22904(‡).
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
authors.affiliation: University of Virginia Exercise and Sport Injury Laboratory, 210 Emmet St South, Charlottesville, VA 22904(¶).
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D064170:Paraspinal Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D011187:Posture; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult