Use of standardised, size-matched clothing enables accurate assessment of percentage body fat by air-displacement plethysmography.

BACKGROUND & AIMS: Air-displacement plethysmography (ADP) is a precise methodology for the examination of body composition. Due to the recommended wearing of tight-fitting and minimal clothing like swimwear during ADP measurements, subject compliance may be reduced. The aim of this study was therefore to evaluate accuracy of alternative body composition measurement methods such as ADP when wearing alternative standardized clothing adapted to the individual size or skinfold thickness (SFT) measuring based on three or seven measurement points.

METHODS

Body composition was measured by ADP and SFT in 48 subjects (30 women, 18 men). ADP measurement was performed in reference clothing (tight-fitting and minimal clothing, ADP) and in scrubs adapted to the individual size (ADP). SFT was measured at seven predefined locations, body composition was calculated based on three or all seven measurements (SFT or SFT).

RESULTS

Compared to ADP, alternative measurement methods resulted in lower values of percentage body fat (P < 0.05) of different levels in each method (ADP - ADP = 9.3 ± 0.2 %; ADP - SFT = 3.5 ± 0.7 % and ADP - SFT = 3.7 ± 0.7 %) in subjects with a body mass index (BMI) of ≥18.5-< 30 kg/m (n = 45). These differences were independent of sex, age, or BMI. According to regression analyses, correct ADP values could be reliably calculated from ADP (Y = 10.622 + 0.924 ∗ X; R = 0.967), which was also possible with SFT and SFT, but not to the same extent.

CONCLUSIONS

Wearing scrubs instead of reference clothing results in a significant underestimation of 9.3 % percentage body fat by ADP measurement. However, if the scrubs are adapted to the individual size, correct values of percentage body fat can be calculated for normal and overweight people. This simplification of the measurement process may lead to increased compliance.