Resumen:
The majority of Spanish adults and children do not engage in enough physical activity to be beneficial for health. There is a need for objective and accurate assessment of the proportion of children meeting the physical activity recommendation for health. Assessing patterns of physical activity both between days (during weekdays and weekend days) and within days is of interest to improve our understanding of the variation in Spanish children's physical activity and to provide efficient intervention programmes. We studied a sample of 221 children: 136 9-year-old children (68 boys and 68 girls) and 85 15-year-old children (36 girls and 49 boys) from 12 urban public schools in Madrid, Spain entered the study. The variables measured were anthropometric characteristics (height, weight, body mass index) and physical activity measured during four consecutive days using the GT1M accelerometer. The result was that younger children were more active and less sedentary than older ones during week and weekend days. Nine-year-old boys and girls achieved significantly (P < 0.05) more moderate to vigorous physical activity (MVPA) and significantly (P < 0.01) less sedentary time than older 15-year-old children. D...