Table 2.
CRF and Other Time‐Varying Covariates From Childhood to Young Adulthood
| Variables | Childhood (n=410)a | Adolescence (n=742)a | Young Adulthood (n=356)a |
|---|---|---|---|
| Sex, % female | 51.2 | 52.2 | 50.0 |
| Age, y | 12.5 (0.3) | 15.5 (0.3) | 22.4 (1.7) |
| VO2max, L/min | 1.96 (0.38) | 2.54 (0.58) | 2.31 (0.84) |
| VO2max, mL/min per kg | 45.6 (4.9) | 43.7 (6.9) | 33.0 (9.8) |
| VO2max, mL/min per kgFFM | 58.9 (4.7) | 56.8 (6.2) | 42.0 (9.5) |
| VO2max, mL/min per kg0.67 | 157 (16) | 167 (28) | 134 (41) |
| VO2max, mL/min per kg0.79 | 100 (10) | 102 (16) | 80 (24) |
| Poor CRF, %b | 8.1 | 14.3 | 31.2 |
| Height, cm | 150 (8) | 165 (8) | 171 (10) |
| Weight, kg | 43.3 (9.3) | 58.1 (9.9) | 69.7 (12.9) |
| Body mass index, kg/m2 | 19.0 (3.2) | 21.3 (3.1) | 23.7 (3.7) |
| Underweight, % | 9.8 | 5.0 | 2.2 |
| Normal weight, % | 73.4 | 79.5 | 68.3 |
| Overweight, % | 13.6 | 12.8 | 23.9 |
| Obese, % | 3.2 | 2.7 | 5.6 |
| Sum of 4 skinfolds, median (interquartile range), mm | 34.4 (27.6–49.5) | 38.6 (28.5–52.4) | 48.2 (35.6–59.6) |
| FFM, kg | 33.2 (5.6) | 44.5 (7.2) | 54.1 (10.9) |
| Maturity stage, %c | |||
| Prepubescent (stage I) | 48.7 | 1.0 | ··· |
| Pubescent (stages II–III) | 35.2 | 5.5 | ··· |
| Post‐pubescent (stages IV–V) | 16.1 | 93.5 | 100.0 |
Data are mean (SD) unless otherwise indicated. CRF indicates cardiorespiratory fitness; FFM, fat‐free mass; VO2max, maximal oxygen uptake (measure of CRF).
a
Numbers are exact number of individuals, from the 791 selected for the present study contributing data at the specific age period.
b
Poor CRF was defined on the basis of the following age‐ and sex‐specific cut points for VO2max (in mL/kg per minute): <41.8 (childhood and adolescence) and <33 (young adulthood) in males and <34.6 (childhood and adolescence) and <24 (young adulthood) in females.
c
According to Tanner stages for pubic hair development.