Validity of Impedance Predictions at Various Levels of Fatness,
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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Results of whole body electrical resistance RES measurements have been proposed as estimates of total body water and of fat-free mass. The validity of RES to predict percent body fat BF was evaluated in a sample of 403 male Mean values age 32.1 yr, stature 178.6 cm, weight 87.5 kg, BF 21.7, and 135 female Mean values age 27.1 yr, stature 164.6 cm, weight 62.6 kg, BF 26.2 military personnel. There was general over-prediction of individuals having lower BF values and under-prediction of individuals having higher BF values using equations supplied by the manufacturer of the RES measurement device. This problem of non-generalizability was not alleviated by 1 re-determination of regression constants using the variables contained in the manufacturers equations on this particular sample 2 incorporation of anthropometric variables in models involving RES and stature HT and 3 weighting of the cases to provide equal power at all percent body fat values. Subcutaneous adipose tissue mass was estimated from skinfold thickness and body surface area. The difference between this subcutaneous adipose tissue mass and total fat mass predicted from hydrodensitometry residual fat was compared with accepted values for essential fat for men and women. In this sample, over-prediction of low BF individuals occurred at approximately the BF value at which predicted residual fat becomes less than accepted essential fat values.
- Anatomy and Physiology