Children and chrono-exercise: Timing of physical activity on school and weekend days depends on sex and obesity status
Bibliographic record
Abstract
Recommendations for physical activity (PA) typically focus on frequency, intensity, duration, and type, but timing (chrono-exercise) is also important. The objective of this study is to describe when children are active on school and weekend days and explore PA timing across sex and body mass index (BMI) categories. 359 children (53% male), aged 9.6 (0.9) y, were categorized as normal weight (≥-1 standard deviations (SD) and <1SD; n = 193), overweight (≥1SD and <2SD; n = 80), or obese (≥2SD; n = 86) using WHO BMIz. Moderate-to-vigorous PA (MVPA) was assessed using ActiGraph LS-7164. The results are described as Mean(SD). ANOVA evaluated MVPA across sexes and BMI categories. Normal weight boys were more active than boys with obesity on school (Δ20.33 min; p < 0.001) and weekend days (Δ15.04 min; p < 0.05). On school days, significant differences existed between 9:00 h-11:00 h and 12:00 h-14:00 h (p < 0.017), while on weekends, smaller differences existed throughout the day. Girls’ MVPA was similar across BMI categories, on all days (p > 0.05). On school days, 12:00 h-13:00 h represented the most active hour for all participants (~14% total daily MVPA). Peak weekend MVPA was distributed across multiple hours. Differences in MVPA timing emerged on school-days and weekends. Timing may be important when examining the nuances of MVPA in relation to sex and bodyweight in children.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".