Effect of race and resistance-training status on the density of fat-free mass and percent fat estimates.
Millard-Stafford, Melinda L., Mitchell A. Collins, Christopher M. Modlesky, Teresa K. Snow, and Linda B. Rosskopf.
1Exercise Physiology Laboratory, Department of Health and Performance Sciences, Georgia Institute of Technology, Atlanta 30332-0110; 2Department of Health, Physical Education, and Sport Science, Kennesaw State University, Kennesaw 30144-5591; and 3Department of Exercise Science and Foods and Nutrition, University of Georgia, Athens, Georgia 30602
APStracts 8:0306A, 2001.
The impact of race and resistance-training status on the assumed density of the fat-free mass (DFFM) and estimates of body fatness via hydrodensitometry (%FatD) vs. a four-component model (density, weight, mineral; %FatD,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 %FatD,W,M. DFFM was not different between B and W (or 1.1 g/ml); however, DFFM in B-RT was significantly lower (1.091 ± 0.012 g/ml; P < 0.05). Therefore, %FatD using the Siri equation was not different from %FatD,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 %FatD,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 DFFM = 1.113 g/ml) did not improve the agreement between %FatD and %FatD,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 DFFM or estimates of %FatD; however, B-RT have a DFFM lower than 1.1 g/ml, leading to an overestimation of %FatD.
Received 16 January 2001; accepted in final form 21 May 2001
APS Manuscript Number A46-1.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 June 2001