From volume to pattern: Sustained moderate-to-vigorous physical activity and its sociodemographic distribution in children and adolescents

Abstract

Most research on children’s and adolescents’ physical activity focuses on total daily moderate-to-vigorous physical activity (MVPA), with limited attention to its temporal structure. This cross-sectional study characterised MVPA accumulation patterns in 513 participants (256 boys, 257 girls; mean age 11.7 ± 3.2 years) from the Basque Country (Spain) using wrist-worn accelerometry (100 Hz; ENMO ≥100 mg; 5-s epochs; GGIR) over seven consecutive days. MVPA bouts were defined using a strict consecutive criterion at thresholds of ≥1, ≥5, and ≥10 minutes. On average, 66.2% of daily MVPA was accumulated in bouts ≥1 minute, 44.7% in bouts ≥5 minutes, and 34.8% in bouts ≥10 minutes. Boys accumulated more total MVPA and a greater proportion in sustained bouts than girls (40.9% vs. 28.8%). Both total and sustained MVPA declined progressively with age. In multivariable models, age (β = −1.93; 95% CI: −2.57 to −1.28) and female sex (β = −14.00; 95% CI: −18.50 to −9.50) were independently associated with lower sustained MVPA (model R² = .126). Sustained MVPA was inversely associated with body mass index after adjustment for age, sex, socioeconomic status, and residential setting (β = −9.05 × 10⁻⁶; p = .028; model R² = .359). These findings indicate that MVPA in youth is predominantly fragmented and that sustained accumulation varies systematically by demographic characteristics.