Ponderal index

The Ponderal Index , also known as the Rohrer Index , is a measure for assessing body weight (physically correct body mass) in relation to body size, similar to the body mass index . It was introduced in 1908 by the Swiss physiologist Fritz Rohrer (1888–1926). In contrast to this, the mass m is divided by the third power of the body size l , i.e. based on a (fictitious) volume instead of an area:

{\ displaystyle PI = {\ frac {m} {l ^ {3}}}}

with in kg and in m. ${\ displaystyle m}$ ${\ displaystyle l}$

Values between 11 and 14 kg / m ³ correspond to normal weight. In contrast to the BMI, according to Ditmier, the Ponderal Index also provides a valid statement for very small and very large body sizes. The reason for this is that the index fulfills the conditions of a dimensionless number of the similarity theory for the influence of body size. The index proposed as early as 1908 (cited in) is even suitable for assessing the birth mass and the mass of small children, even if the normal values then roughly double, as an expression of the relatively short leg lengths. The normal value for 12-month-old children is 24 kg / m ³ .

For infants and young children, however, the PI is often calculated using the following formula:

{\ displaystyle PI _ {\ mathrm {k}} = 100 \, {\ frac {m} {l ^ {3}}}}

with in g and in cm. ${\ displaystyle m}$ ${\ displaystyle l}$

The numerical values PI _k are then smaller than PI by a factor of 10 . The first formula should therefore be used uniformly for all body sizes, which is based on the SI base units meter (m) and kilogram (kg) of the International System of Units .

Sample table


height	Weight for PI = 11	Weight for PI = 14
150 cm	37 kg	47 kg
155 cm	41 kg	52 kg
160 cm	45 kg	57 kg
165 cm	49 kg	63 kg
170 cm	54 kg	69 kg
175 cm	59 kg	75 kg
180 cm	64 kg	82 kg
185 cm	70 kg	89 kg
190 cm	75 kg	96 kg
195 cm	82 kg	104 kg
200 cm	88 kg	112 kg

literature

↑ ^a ^b Lawrence F. Ditmier: New Developments in Obesity Research . Nova Science Publishers, Hauppauge, New York 2006, ISBN 1-60021-296-4
↑ ^a ^b Fritz Rohrer: The index of body fullness as a measure of nutritional status, Münchner Med. Wschr. 68: 580-582 (1921)

^ Peter Christoph Biel: Physical development after intrauterine dystrophy. Evaluation & follow-up of the birth cohorts 1982–1994 . Dissertation University of Hamburg. on-line

↑ Fritz Rohrer: A new formula for determining body fullness . Corresponding sheets of the German Society for Anthropology, Ethnology and Prehistory. Volume 39, 1908, No. 1/2

↑ DP Davies: Size at birth and growth in the first year of life of babies who are overweight and underweight at birth , Proc. Nutr. Soc. 39: 25-33 (1980)

Web links

[Ditmier-1] Lawrence F. Ditmier: New Developments in Obesity Research . Nova Science Publishers, Hauppauge, New York 2006, ISBN 1-60021-296-4

[rohrer-2] Fritz Rohrer: The index of body fullness as a measure of nutritional status, Münchner Med. Wschr. 68: 580-582 (1921)

[3] Peter Christoph Biel: Physical development after intrauterine dystrophy. Evaluation & follow-up of the birth cohorts 1982–1994 . Dissertation University of Hamburg. on-line

[4] Fritz Rohrer: A new formula for determining body fullness . Corresponding sheets of the German Society for Anthropology, Ethnology and Prehistory. Volume 39, 1908, No. 1/2

[5] DP Davies: Size at birth and growth in the first year of life of babies who are overweight and underweight at birth , Proc. Nutr. Soc. 39: 25-33 (1980)