Table 2. CRF and Other Time‐Varying Covariates From Childhood to Young Adulthood
VariablesChildhood (n=410)aAdolescence (n=742)aYoung Adulthood (n=356)a
Sex, % female51.252.250.0
Age, y12.5 (0.3)15.5 (0.3)22.4 (1.7)
VO2max, L/min1.96 (0.38)2.54 (0.58)2.31 (0.84)
VO2max, mL/min per kg45.6 (4.9)43.7 (6.9)33.0 (9.8)
VO2max, mL/min per kgFFM58.9 (4.7)56.8 (6.2)42.0 (9.5)
VO2max, mL/min per kg0.67157 (16)167 (28)134 (41)
VO2max, mL/min per kg0.79100 (10)102 (16)80 (24)
Poor CRF, %b 8.114.331.2
Height, cm150 (8)165 (8)171 (10)
Weight, kg43.3 (9.3)58.1 (9.9)69.7 (12.9)
Body mass index, kg/m219.0 (3.2)21.3 (3.1)23.7 (3.7)
Underweight, %9.85.02.2
Normal weight, %73.479.568.3
Overweight, %13.612.823.9
Obese, %3.22.75.6
Sum of 4 skinfolds, median (interquartile range), mm34.4 (27.6–49.5)38.6 (28.5–52.4)48.2 (35.6–59.6)
FFM, kg33.2 (5.6)44.5 (7.2)54.1 (10.9)
Maturity stage, %c
Prepubescent (stage I)48.71.0···
Pubescent (stages II–III)35.25.5···
Post‐pubescent (stages IV–V)16.193.5100.0
  • 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.