The Goldilocks day for preschoolers' health outcomes: A compositional data analysis of 24-H movement behaviors on weekdays and weekends.

Objective: Preschool children's activity patterns differ between weekdays and weekends. Weekdays are constrained by structured educational activities and parental commitments, which limit flexibility, while weekends provide opportunities for extra sleep (SLP), physical activity (PA), and reduced sedentary behavior (SB). This study aims to estimate optimal activity durations for both weekdays and weekends, based on the development of executive function (EF), fundamental movement skills (FMS), and physical fitness (PF) in preschool children. Methods: A total of 289 preschool children aged 3-6 years from four kindergartens in Zhejiang Province participated. PA and SLP were objectively measured using accelerometers and the Children's Sleep Quality Questionnaire. EF, which includes working memory, inhibitory control, and cognitive flexibility, was measured using the Early Years Toolbox (EYT). FMS were assessed using the test of gross motor development-3rd edition (TGMD-3), and PF was evaluated according to the National Physical Fitness Measurement Manual (Preschool Children Section). Compositional data regression models were applied to examine the relationship between 24-h movement behaviors and health outcomes on weekdays and weekends. Optimal time-use compositions for each outcome were estimated, and 3D quaternary plots were generated to define the Goldilocks Day at the center of the overlapping regions. Results: 24-h movement behaviors were significantly correlated with EF (weekdays: F = 5.4, Conclusion: This study provides recommendations for time allocation on weekdays and weekends to support the healthy development of preschool children.