Validity of Impedance Predictions at Various Levels of Fatness,
Abstract
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 manufacturer's 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1986
- Accession Number
- ADA172235
Entities
People
- James A. Hodgdon
- Patrica I. Fitzgerald
Organizations
- United States Army Research Institute of Environmental Medicine