Assessing Physical Activity In Girls Using Accelerometry - 60s Versus 10s Sampling Intervals
Bibliographic record
Abstract
Children exhibit physical activity patterns mainly comprised of sporadic and intermittent bouts, each lasting under 15s in duration. Despite this fact, most studies utilize a 60s accelerometry sampling interval to objectively quantify physical activity in youths. This relatively long sampling interval may underestimate children's true physical activity behaviour. PURPOSE: To assess the difference in intensity, duration and number of continuous bouts of physical activity in children and adolescents when using accelerometry intervals of 60s vs. 10s. METHODS: A total of 106 girls and adolescents (mean = 13.0 ± 2.6 yrs old) wore ActiGraph GT1M accelerometers for all waking hours (except while bathing, swimming, etc.) over seven days. Accelerometers were set at 10s epochs and the raw data was subsequently re-integrated into 60s epochs. From data of both epoch lengths, daily bouts of moderate (MPA; 3-5.9 METs), vigorous (VPA; 6-8.9 METs) and very vigorous (VVPA; ≥9 METs) activities were quantified using a Visual Basic data reduction program. The number of continuous 5 min, 10 min and 20 min bouts at each intensity was also calculated. RESULTS: There was no difference in total MPA minutes between the 10s and 60s analysis. Total VPA, and VVPA were 80.4%, and 61.5% greater in the 10s sampling than in the 60s integrated sampling, respectively (p<0.01). When examining continuous bouts of activity, the 10s analysis generally resulted in more continuous bouts compared with the 60s analysis, especially when examining 5 min bouts of MPA (19.1%), 20 min bouts of VPA (14.6%), and of VVPA (0.9%)(p<0.01). CONCLUSION: The commonly used 60s accelerometry sampling interval underestimates the amount of physical activity that children and adolescents engage in, especially at the higher intensity levels. Thus, a sampling interval of 10s or less is warranted to better assess physical activity levels of different intensities in children and adolescents.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".