Validity and Reproducibility of a New Treadmill Protocol: The Fitkids Treadmill Test. Med. Sci. Sports Exerc., Vol. 47, No. 10, pp. 2241–2247, 2015. Purpose: This study aimed to investigate the validity and reproducibility of a new treadmill protocol in healthy children and adolescents: the Fitkids Treadmill
Test (FTT). Methods: Sixty-eight healthy children and adolescents (6–18 yr) were randomly divided into a validity group (14 boys and 20 girls; mean T SD age, 12.9 T 3.6 yr) that performed the FTT and Bruce protocol, both with respiratory gas analysis within 2 wk, and a reproducibility group (19 boys and 15 girls; mean T SD age, 13.5 T 3.5 yr) that performed the FTT twice within 2 wk. A subgroup of 21 participants within the reproducibility group performed both FTT with respiratory gas analysis. Time to exhaustion (TTE)
was the main outcome of the FTT. Results: V˙ O2peak measured during the FTT showed excellent correlation with V˙ O2peak measured during the Bruce protocol (r = 0.90; P G 0.01). Backward multiple regression analysis provided the following prediction equations for V˙ O2peak (LIminj1) for boys and girls, respectively: V˙ O2peak FTT ¼ j0:748 þ ð0:117 TTEFTTÞ þ ð0:032 bodymassÞ þ 0:263, and
V˙ O2peak FTT ¼ j0:748 þ ð0:117 TTEFTTÞ þ ð0:032 bodymassÞ [R2 ¼ 0:935; SEE ¼ 0:256LI min j1]. Cross-validation of the regression model showed an R2 value of 0.76. Reliability statistics for the FTT showed an intraclass correlation coefficient of 0.985 (95% confidence interval, 0.971–0.993; P G 0.001) for TTE. Bland–Altman analysis showed a mean bias of j0.07 min, with limits of agreement between +1.30 and j1.43 min. Conclusions: Results suggest that the FTT is a useful treadmill protocol with good validity
and reproducibility in healthy children and adolescents. Exercise performance on the FTT and body mass can be used to adequately predict V˙ O2peak when respiratory gas analysis is not available.