Samenvatting

Background. Recent research has shown that the Fitkids Treadmill Test (FTT) is a valid
and reproducible exercise test for the assessment of aerobic exercise capacity in children and
adolescents who are healthy.
Objective. The study objective was to provide sex- and age-related normative values for
FTT performance in children and adolescents who were healthy, developing typically, and 6
to 18 years of age.
Design. This was a cross-sectional, observational study.
Methods. Three hundred fifty-six children and adolescents who were healthy (174 boys
and 182 girls; mean age12.9 years, SD3.7) performed the FTT to their maximal effort to
assess time to exhaustion (TTE). The least-mean-square method was used to generate sex- and
age-related centile charts (P3, P10, P25, P50, P75, P90, and P97) for TTE on the FTT.
Results. In boys, the reference curve (P50) showed an almost linear increase in TTE with
age, from 8.8 minutes at 6 years of age to 16.1 minutes at 18 years of age. In girls, the P50 values
for TTE increased from 8.8 minutes at 6 years of age to 12.5 minutes at 18 years of age, with
a plateau in TTE starting at approximately 10 years of age.
Limitations. Youth who were not white were underrepresented in this study.
Conclusions. This study describes sex- and age-related normative values for FTT performance
in children and adolescents who were healthy, developing typically, and 6 to 18 years
of age. These age- and sex-related normative values will increase the usefulness of the FTT in
clinical practice.