Reliability and validity of bioelectrical impedance in determining body composition | JoVE Visualize

Reliability and validity of bioelectrical impedance in determining body composition

¹Department of Health, Physical Education, and Recreation, University of Houston, Texas 77004.

Journal of Applied Physiology (Bethesda, Md. : 1985)|February 1, 1988

View abstract on PubMed

Summary

The bioelectrical impedance method (BIA) for body composition is reliable but less accurate than skinfold measurements. BIA is comparable to body mass index (BMI) for estimating body fat percentage.

Area of Science:

Exercise Physiology
Human Biology
Biomedical Engineering

Background:

Accurate body composition measurement is crucial for health assessment.
Standard anthropometric methods and newer bioelectrical impedance analysis (BIA) are commonly used.
Comparing the reliability and validity of these methods is essential for clinical practice.

Purpose of the Study:

To assess the reliability and validity of the bioelectrical impedance method (BIA) for body composition analysis.
To compare the accuracy of BIA with standard anthropometric methods, including skinfold measurements and hydrostatic weighing.
To evaluate BIA's performance against body mass index (BMI).

Main Methods:

BIA, skinfold fat, and hydrostatic measurements were taken on 44 women and 24 men.
Subjects underwent four tests by two testers on two separate days to assess reliability.
Generalizability theory was applied to analyze reliability and measurement error.
Cross-validation was performed using an additional 50 men and 82 women.

Main Results:

All methods (BIA, skinfold, hydrostatic) demonstrated high reliability (Rxx = 0.957-0.987) with low standard errors (0.9-1.5% fat).
BIA cross-validation correlations (0.71-0.76) were significantly lower than sum of seven skinfolds equations (0.92 for men, 0.88 for women).
BIA accuracy was comparable to BMI (correlations 0.75-0.74), with height and weight being major factors in BIA equations.

Conclusions:

BIA is a reliable method for assessing body composition.
Skinfold measurements offer higher accuracy for estimating body fat percentage compared to BIA.
BIA serves as a viable alternative to BMI for body composition assessment, particularly when hydrostatic weighing or detailed skinfold analysis is unavailable.