Temporal and intensity-distribution differences in physical activity among schoolchildren and adolescents from the Basque Country: weekday-weekend and school-after-school comparisons

Introduction This study examined temporal and intensity-distribution differences in objectively measured physical activity among schoolchildren and adolescents from the Basque Country, Spain, comparing weekdays with weekend days, Saturday with Sunday, and school time with after-school time. Methods Raw wrist-accelerometer data were reprocessed for 540 participants in the Mugikertu study. The final exact-linked regional sample comprised 503 participants aged 6–17 years from 42 schools, contributing 2,979 valid days. Euclidean Norm Minus One (ENMO), waking average acceleration, intensity gradient, M30, M60, and time in moderate (MPA), vigorous (VPA), and moderate-to-vigorous physical activity (MVPA) were derived in GGIR. Pediatric non-dominant-wrist thresholds were applied (MPA 201.4–<707 mg; VPA ≥ 707 mg). Paired comparisons and multilevel models examined day-type differences, with days nested within participants and participants within schools. Results Mean MVPA was 65.19 ± 34.85 min/day, and 51.1% of participants accumulated an average of ≥60 min/day. Weekday values exceeded weekend values for 24-h ENMO (47.97 ± 17.82 vs. 41.28 ± 20.46 mg) and MVPA (68.25 ± 35.31 vs. 59.12 ± 41.94 min/day; mean difference 9.13 min/day, 95% CI 6.51–11.75). Sunday MVPA was lower than Saturday MVPA (55.81 ± 45.30 vs. 64.09 ± 48.86 min/day). During weekdays, MVPA density was lower in the 09:00–14:30 school window than in the 14:30–22:00 after-school window (4.49 ± 2.82 vs. 5.12 ± 2.89 min/h). The weekday-weekend association varied by age but not by sex or socioeconomic context for MVPA. Conclusion In this Basque regional sample, activity volume and intensity were lower on weekends, particularly Sundays, and declined sharply with age. School time contributed meaningfully to daily activity, but after-school time showed slightly higher MVPA density. The regional context and the age-specific pattern should be considered when transferring these findings to other settings.