Table 1.
Age- and sex-specific constants for conversion of body density, water, and mineral to %FM in children and youth.
| Age (years) | Females | Males | ||||
|---|---|---|---|---|---|---|
| D FFM | C1 | C2 | D FFM | C1 | C2 | |
| 7–9 | 1.079 | 5.451 | 5.052 | 1.081 | 5.400 | 4.996 |
| 9–11 | 1.082 | 5.376 | 4.968 | 1.084 | 5.327 | 4.914 |
| 11–13 | 1.086 | 5.279 | 4.861 | 1.087 | 5.255 | 4.835 |
| 13–15 | 1.092 | 5.141 | 4.708 | 1.094 | 5.098 | 4.660 |
| 15–17 | 1.094 | 5.098 | 4.660 | 1.096 | 5.055 | 4.612 |
| 17–20 | 1.095 | 5.076 | 4.636 | 1.099 | 5.002 | 4.554 |
| 20–25 | 1.096 | 5.055 | 4.612 | 1.100 | 4.971 | 4.519 |
%FM: percent fat mass; Db: body density; D FFM: fat-free mass density; C1: constant 1; C2: constant 2.
*Calculation of percent fat mass (%FM) using age- and sex-specific values for the density of the FFM: %FM = [(C1/Db) − C2] ∗ 100, where Db represents body density. Adapted from Lohman [10].