How many daily steps are really enough for adolescents? A cross-validation study

espanolEl proposito principal del presente estudio fue comparar la precision de los umbrales de pasos diarios totales asociados a la recomendacion de 60 minutos por dia de actividad fisica moderada-vigorosa en adolescentes. Un total de 156 adolescentes, 87 varones y 69 mujeres, participaron en el presente estudio. La actividad fisica moderada-vigorosa y pasos se evaluaron objetivamente con acelerometros GT3X durante ocho dias consecutivos. Se calculo la precision de los siguientes umbrales de pasos diarios totales (varones/mujeres): 9.930, 11.714, 12.000, 11.000/10.500, 14.000/11.500, 13.000/12.000, 8.500/7.500, 11.500/9.000, 10.500/9.500, 12.118, 12.118/12.605 y 10.000. Los resultados de precision para los puntos de corte de los pasos diarios ajustados y no ajustados variaron de bajo a alto. Para los pasos diarios no ajustados, los puntos de corte 11.000 para los varones y 10.500 para las mujeres mostraron los mejores resultados: Sensibilidad= 0,85; Especificidad= 0,94; Indice de Youden= 0,78; Proporcion de acuerdo= 0,93, y coeficiente de Kappa= 0,67, p Especificidad= 0,95; Indice de Youden= 0,72; Proporcion de acuerdo= 0,93, y coeficiente de Kappa= 0,65, p EnglishThe main purpose of the present study was to compare the accuracy of total daily steps thresholds associated to the recommended 60 min per day moderate-to-vigorous physical activity in adolescents. A total of 156 adolescents, 87 males and 69 females, participated in the present study. Objectively-measured moderate-to-vigorous physical activity and steps were assessed by GT3X accelerometers for eight consecutive days. The accuracy of the following total daily steps thresholds was calculated (males/females): 9,930, 11,714, 12,000, 11,000/10,500, 14,000/11,500, 13,000/ 12,000, 8,500/7,500, 11,500/9,000, 10,500/9,500, 12,118, 12,118/12,605, and 10,000. The results of accuracy both uncensored and censored total daily steps cut-off points ranged from low to high. For the uncensored total daily steps, the cut-off 11,000 for males and 10,500 for females showed the best results: Sensitivity = .85; Specificity = .94; Youden’s index = .78; Proportion of agreement = .93, and Kappa coefficient = .67, p