Fat-free mass estimation by the two-electrode impedance method.
In 202 healthy subjects (81 men, 121 women) aged 12-71 y, impedance (Z) was measured with a two-electrode analyzer. Fat-free mass was assessed by hydrodensitometry (FFMd). This population was randomized into two groups for cross-validation. In group 1 the relationship between ht2/Z at 1 MHz and FFMd was highly significant (r = 0.85, P less than 0.001). The equation for predicting FFMd from impedance, height2, weight, and age obtained in group 1 (r = 0.97) was applied to group 2 (r = 0.96) without reduction in r value. The accuracy of this equation was not different between men and women or between active and sedentary people. These data indicate that the two-electrode impedance method is a reliable and valid approach not only for the determination of extracellular water (as previously shown) but also for that of FFM.
Laboratory of Physiology, Medical School, University of Caën, France.
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A
Boulier
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J
Fricker
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AL
Thomasset
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M
Apfelbaum
D000293:Adolescent; D000328:Adult; D000368:Aged; D000886:Anthropometry / Q000379:methods*; D001823:Body Composition; D002648:Child; D003720:Densitometry; D004553:Electric Conductivity; D004594:Electrophysiology / Q000379:methods*; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D012044:Regression Analysis