title: Intraindividual Variability in Test-Retest Air Displacement Plethysmography Measurements of Body Density for Men and Women.
abstract: Air displacement plethysmography (ADP) is a popular method for estimating body density (Db). Most ADP tests are performed once, with test-retest investigations scarce. Therefore, we investigated test-retest reliability of ADP. Active men (n = 25) and women (n = 25) volunteered and followed standard pretest guidelines. Participants wore dry, form-fitting swimwear and manufacturer-supplied swim caps. In a single session, two ADP trials with measured thoracic gas volume (TGV) were performed without repositioning participants. Separate 2 (sex) × 2 (ADP trial) repeated-measures ANOVAs were performed to investigate within-between comparisons of Db, TGV, body volume (Vb), and relative fatness (%BF). Paired t tests were used to investigate significant differences as appropriate. The Bland and Altman technique was used to depict individual intertrial variations. For all analyses, α =.05. A significant main effect for sex was found; men were lower in %BF and higher in all other variables compared with women. Individual variability was notable (ADP1-ADP2). The range of individual intertrial differences were larger for women than men, respectively, for Db (-0.0096-0.0045 g/cc; -0.0019-0.0054 g/cc), TGV (-0.623-1.325 L; -0.584-0.378 L), Vb (-0.249-2.10 L; -0.234-0.397 L), and %BF (-2.1-4.4%; -0.2-0.9%). When assessing body composition of women via ADP or using Db from ADP in a multicomponent model, at least two trials with measured TGV should be performed and the average of the values recorded and reported.
authors: Ann L
authors: AL
authors: Gibson
authors: Jenevieve L
authors: JL
authors: Roper
authors: Christine M
authors: CM
authors: Mermier
mesh_terms: D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D005740:Gases / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography / Q000379:methods*; D015203:Reproducibility of Results; D012119:Respiration; D013550:Swimming; D055815:Young Adult
chemical_list: D005740:Gases
keywords: BodPod; adults; body composition