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.
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.
BACKGROUND: Muscle quantity at intensive care unit (ICU) admission has been independently associated with mortality. In addition to quantity, muscle quality may be important for survival. Muscle quality is influenced by fatty infiltration or myosteatosis, which can be assessed on computed tomography (CT) scans by analysing skeletal muscle density (SMD) and the amount of intermuscular adipose tissue (IMAT). We investigated whether CT-derived low skeletal muscle quality at ICU admission is independently associated with 6-month mortality and other clinical outcomes.METHODS: This retrospective study included 491 mechanically ventilated critically ill adult patients with a CT scan of the abdomen made 1 day before to 4 days after ICU admission. Cox regression analysis was used to determine the association between SMD or IMAT and 6-month mortality, with adjustments for Acute Physiological, Age, and Chronic Health Evaluation (APACHE) II score, body mass index (BMI), and skeletal muscle area. Logistic and linear regression analyses were used for other clinical outcomes.RESULTS: Mean APACHE II score was 24 ± 8 and 6-month mortality was 35.6%. Non-survivors had a lower SMD (25.1 vs. 31.4 Hounsfield Units (HU); p < 0.001), and more IMAT (17.1 vs. 13.3 cm(2); p = 0.004). Higher SMD was associated with a lower 6-month mortality (hazard ratio (HR) per 10 HU, 0.640; 95% confidence interval (CI), 0.552-0.742; p < 0.001), and also after correction for APACHE II score, BMI, and skeletal muscle area (HR, 0.774; 95% CI, 0.643-0.931; p = 0.006). Higher IMAT was not significantly associated with higher 6-month mortality after adjustment for confounders. A 10 HU increase in SMD was associated with a 14% shorter hospital length of stay.CONCLUSIONS: Low skeletal muscle quality at ICU admission, as assessed by CT-derived skeletal muscle density, is independently associated with higher 6-month mortality in mechanically ventilated patients. Thus, muscle quality as well as muscle quantity are prognostic factors in the ICU.TRIAL REGISTRATION: Retrospectively registered (initial release on 06/23/2016) at ClinicalTrials.gov: NCT02817646 .
