Effect of race and resistance training status on the density of fat-free mass and percent fat estimates.
The impact of race and resistance training status on the assumed density of the fat-free mass (D(FFM)) and estimates of body fatness via hydrodensitometry (%Fat(D)) vs. a four-component model (density, water, mineral; %Fat(D,W,M)) were determined in 45 men: white controls (W; n = 15), black controls (B; n = 15), and resistance-trained blacks (B-RT; n = 15). Body density by hydrostatic weighing, body water by deuterium dilution, and bone mineral by dual-energy X-ray absorptiometry were used to estimate %Fat(D,W,M). D(FFM) was not different between B and W (or 1.1 g/ml); however, D(FFM) in B-RT was significantly lower (1.091 +/- 0.012 g/ml; P < 0.05). Therefore, %Fat(D) using the Siri equation was not different from %Fat(D,W,M) in W (17.5 +/- 5.0 vs. 18.3 +/- 5.4%) or B (14.9 +/- 5.6 vs. 15.7 +/- 5.7%) but significantly overestimated %Fat(D,W,M) in B-RT (14.0 +/- 5.9 vs. 10.4 +/- 6.0%; P < 0.05). The use of a race-specific equation (assuming D(FFM) = 1.113 g/ml) did not improve the agreement between %Fat(D) and %Fat(D,W,M), resulting in a significantly greater mean (+/-SD) discrepancy for B (1.7 +/- 1.8% fat) and B-RT (6.2 +/- 4.3% fat). Thus race per se does not affect D(FFM) or estimates of %Fat(D); however, B-RT have a D(FFM) lower than 1.1 g/ml, leading to an overestimation of %Fat(D).
Millard-Stafford
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ML
Exercise Physiology Laboratory, Department of Health and Performance Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332-0356, USA. mindy.millardstafford@hps.gatech.edu
Collins
M A
MA
Modlesky
C M
CM
Snow
T K
TK
Rosskopf
L B
LB
D000273:Adipose Tissue / Q000502:physiology; D000328:Adult; D044383:Black People; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D014867:Water; D044465:White People
D014867:Water