Drill Index

The Broca index is a formula that was developed in 1871 by the French physician and surgeon Paul Broca (1824-1880) from studies carried out on soldiers. It is a quick and easy way to determine the reference body mass of an adult person from their height:

Calculation

Broca's index is calculated from the following formulaː

P(kg)=E(cm)− − 100{displaystyle P(kg)=E(cm)-100}

where P is the mass, expressed in kg, and E is the height, measured in cm. The value obtained varies depending on the sex:

• Men: ±10%
• Women: ±15%

For example, the reference body weight for a 180 cm male will be equal to:

ː P (kg) = (180 - 100) ± (180-100) × 0.1 = 80 ± 8 = (88-72) kg

that is, the reference weight for men of 180 cm, according to the Broca index, would be between 72 and 88 kg.

Although this index is still used in some scientific studies, it has serious limitations when medical studies are carried out on individuals with certain anthropometric characteristics^,. In clinical practice, other coefficients are used, such as the body mass index also known as the Quetelet index, to estimate the reference weight of an individual.

Observation

A frequent error in the use and interpretation of the data obtained with this index is to believe that it is the value corresponding to the weight that a particular person should have. Nothing is further from the truth: it is the characteristic average weight of the population that has characteristics similar to those of the individual being analyzed.