A Comparison of the Fat-Free Mass of Young Adults Estimated by Anthropometry, Body Density and Total Body Potassium Content

1972 ◽  
Vol 43 (3) ◽  
pp. 469-475 ◽  
Author(s):  
J. Womersley ◽  
K. Boddy ◽  
Priscilla C. King ◽  
J. V. G. A. Durnin

1. The fat-free mass (FFM) of ten male and ten female subjects was calculated from measurement of (i) height and weight, (ii) skinfold thickness, (iii) body density, (iv and v) total body potassium by two different methods. All the subjects were apparently healthy and in the medium range of body build and they were mainly young adults. 2. The mean FFM of the ten male subjects was similar as calculated by all methods, although comparisons between pairs of methods sometimes produced discrepancies of up to 2 kg. 3. Agreement was less good for the females but, with the exception of one of the potassium methods, still reasonable. 4. The potassium content of the FFM as mEq K/kg of FFM, was compared with the direct analysis of Forbes, Gallup & Hursh (1961) on four male cadavers. The agreement was close for the men but the K content of the FFM in women was lower than that for men. This difference is discussed.

1975 ◽  
Vol 39 (5) ◽  
pp. 825-830 ◽  
Author(s):  
S. Chien ◽  
M. T. Peng ◽  
K. P. Chen ◽  
T. F. Huang ◽  
C. Chang ◽  
...  

On 27 men and 6 women, total body density and 10 skinfolds were measured 12 yr apart, with the mean age increasing from 31 to 43 yr. The increase in skinfold thickness was found to be related to the increase in total body adiposity, calculated from hydrostatic weighing. The external adipose tissue was calculated from the mean skinfold thickness and body surface area. Variations in total adiposity among the population studied as well as changes in total adiposity with age showed a characteristic distribution with approximately two-thirds on the surface and one-third in the interior. The essential body mass or total adipose mass determined by hydrostatic weighing was compared with the values obtained by water-immersion volumetry, total body potassium counting, and skinfold measurements. Teh volumetric and skinfold determinations gave better estimates of these parameters than total body potassium counting.


1983 ◽  
Vol 65 (4) ◽  
pp. 407-414 ◽  
Author(s):  
D. B. Morgan ◽  
L. Burkinshaw

1. Many previous reports have shown that the ratio of total body potassium to fat-free tissue mass is, on average, higher in men than in women. 2. In an attempt to explain this finding we have re-examined our own data and data taken from the literature. Our own data comprise measurements on 333 healthy people (196 men and 137 women). In all subjects we measured total body potassium and estimated fat-free mass from body weight and skinfold thickness; in 91 of them (62 men and 29 women) we measured, in addition, total body nitrogen. 3. We have used the statistical technique of factor analysis to obtain unbiased estimates of the relationships between the three quantities measured in the smaller group. The validity of the relationships is supported by the results from the larger group and by data from the literature. 4. The average values of total body potassium and fat-free mass are greater in men than in women, but the relationship between the two variables is identical in men and women. The relationship has a positive intercept on the axis of fat-free mass, so that the ratio of total body potassium to fat-free mass increases with fat-free mass. The higher ratio in men compared with women can therefore be explained by a difference in size alone. 5. The relationship between total body potassium and total body nitrogen has a negligible intercept. Therefore the ratio of total body potassium to total body nitrogen does not change with size. 6. These findings suggest that, on average, the fat-free mass is made up of a fixed component of approximately 9 kg of tissue containing no potassium or nitrogen, and a variable component with a potassium to nitrogen ratio of about 1.81 mmol/g.


1981 ◽  
Vol 61 (4) ◽  
pp. 457-462 ◽  
Author(s):  
L. Burkinshaw ◽  
D. B. Morgan ◽  
N. P. Silverton ◽  
R. D. Thomas

1. The amount of lean tissue in the body can be assessed by measuring total body nitrogen, total body potassium or fat-free mass. To compare these techniques we have measured total body nitrogen, total body potassium and fat-free mass in 91 healthy subjects (62 males, 29 females). 2. Total body nitrogen in the women and civilian men agreed closely with the few values reported previously and was closely related to total body potassium and fat-free mass. 3. The simplest estimate of total body nitrogen in a subject whose body content has not been measured is the mean value for healthy people of the same sex. The standard deviation of individual values about this mean is 253 g. The precision of the estimate can be improved considerably by predicting body nitrogen from fat-free mass (156 g) and somewhat more by predicting it from body potassium (115 g). The error of measuring total body nitrogen directly is approximately 76 g. 4. When an individual's total body potassium is measured in a search for potassium depletion, the observed value must be compared with the value expected if the subject were healthy. The standard deviation of the healthy values about the group means is 408 mmol. The precision of the estimate can be improved by predicting total body potassium from fat-free mass (sd 237 mmol), and rather more by predicting it from total body nitrogen (sd 186 mmol). If gross body composition is normal, measurement of total body nitrogen has little advantage over measurement of fat-free mass by the anthropometric technique. 5. These results suggest that the simpler measure of fat-free mass from body weight and skinfold thickness has a major role in the assessment of total body nitrogen, and thus lean body tissue, in the individual.


2001 ◽  
Vol 281 (1) ◽  
pp. E1-E7 ◽  
Author(s):  
Zimian Wang ◽  
F. Xavier Pi-Sunyer ◽  
Donald P. Kotler ◽  
Jack Wang ◽  
Richard N. Pierson ◽  
...  

Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water ( E/I) is the major factor leading to between-individual variation in the TBK/FFM ratio. The present study provides a conceptual framework for examining the separate TBK/FFM determinants and suggests important limitations of the TBK/FFM method used in estimating total body fat in humans and other mammals.


2017 ◽  
Vol 38 (12) ◽  
pp. 890-896
Author(s):  
Helouane Ázara ◽  
Paulo Farinatti ◽  
Adrian Midgley ◽  
Fabrício Vasconcellos ◽  
Patrícia Vigário ◽  
...  

AbstractThe main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P<0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P<0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P<0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.


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