DETERMINATION OF PERCENT BODY-FAT BY THE NEWLY DEVELOPED SULFUR-HEXAFLUORIDE DILUTION METHOD AND AIR DISPLACEMENT PLETHYSMOGRAPHY

The reliability and validity of two newly developed densitometric meth ods for determining the human body volume and percent body fat (%FAT), the sulfur hexafluoride dilution method (SHF) and air displacement pl ethysmography (ADP), were evaluated in comparison with the underwater weighing method (UWW). Seven healthy male volunteers (age 31 to 44, me an height 166.0 cm, weight 61.4 kg) participated in this study. The sa me-day test-retest coefficients of variation (CVs) for body volume and %FAT measurements were not significantly different among the three me thods. SHF and UWW showed a strong correlation in terms of body volume and %FAT, with the correlation coefficients (r) being 0.9997 and 0.98 6, respectively. The correlation between ADP and UWW was slightly weak er (r=0.9997 for body volume and 0.907 for %FAT). However, body volume s measured by SHF and ADP were significantly different from that by UW W when compared by mean values. Such differences were also found for % FAT measurements. The regression lines of body volume measured by SHF and ADP on that by UWW were almost equivalent to the line of identity. However, those of %FAT measured by SHF and ADP on that by UWW were si gnificantly different from the line of identity. Because the reliabili ty of SHF and ADP appeared to be high, further validation and improvem ent are required and worth doing.