title: Reproducibility and validity of A-mode ultrasound for body composition measurement and classification in overweight and obese men and women.
abstract: Identifying portable methods to measure body composition may be more advantageous than using body mass index (BMI) to categorize associated health consequences.
  
  
  OBJECTIVE
  To compare the validity and reliability of a portable A-mode ultrasound (US) to a criterion three compartment model (3C) for the measurement of body composition.
  
  
  METHODS
  Forty-seven overweight and obese subjects participated in this study. Body composition was measured once via air displacement plethysmography for body density (Bd) and bioelectrical impedance spectroscopy for total body water (TBW) for the 3C calculations. Ultrasound measurements (BodyMetrix, Intelametrix) were made using an A mode, 2.5- MHz transmitter. All measurements were made on the right side of the body at 7 skinfold sites. The US software calculated percent body fat (%BF), fat mass (FM) and fat free mass (FFM) from the 7-site Jackson and Pollock equation.
  
  
  RESULTS
  %BF and FM, respectively, measured by the US (29.1 ± 6.5%; 27.4 ± 8.1 kg) was significantly lower compared to the 3C model (33.7 ± 7.6%; 31.8 ± 9.8 kg; p<0.0005). Fat free mass was significantly higher for the US (66.7 ± 13.0 kg) compared to the 3C model (62.3 ± 12.6; p = 0.001). The US demonstrated respectable reliability for %BF, FM, and FFM with intraclass correlation coefficients (ICC) ranging from 0.84-0.98 and standard error of the measurement (SEM) values and 2.2%BF, 1.9 kg, 1.9 kg, respectively.
  
  
  CONCLUSIONS
  The US was found to under predict %BF and FM with large deviations from the criterion (n = 10 >4%BF error). While the US was not valid in this population, it was reliable producing results with minimal error, suggesting this technique may be effective for tracking changes in a weight loss or clinical setting.
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors.forename: Abbie E
authors.initials: AE
authors.lastname: Smith-Ryan
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors.forename: Sarah N
authors.initials: SN
authors.lastname: Fultz
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors.forename: Malia N
authors.initials: MN
authors.lastname: Melvin
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors.forename: Hailee L
authors.initials: HL
authors.lastname: Wingfield
authors.affiliation: Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina, United States of America.
authors.forename: Mary N
authors.initials: MN
authors.lastname: Woessner
mesh_terms: D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009765:Obesity / Q000000981:diagnostic imaging*; D050177:Overweight / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D014463:Ultrasonography