Leisure-Time Physical Activity Levels Among Canadian Adolescents, 1981–1998
Bibliographic record
Abstract
Background: In recent years, it has been noted that children and youth are physically inactive, and physical activity levels have declined over the past decades. However, few empirical studies have been conducted to test this assumption. Therefore, the purpose of this study was to examine leisure-time physical activity levels among Canadian adolescents 12–19 years of age. Methods: Age, sex, geographic, and temporal trends in leisure-time physical activity energy expenditure (AEE) were examined using data from 5 national surveys conducted between 1981 and 1998. AEE was calculated from participants’ questionnaire responses on physical activity participation. General linear models were used to examine the differences in AEE across survey years, geographic regions, sexes, and age groups. Results: Males and 12–14-year-olds displayed greater AEE than females and 15–19-year-olds, respectively, and AEE was lowest in Quebec and highest in the West. AEE increased between the 1981 and 1988 surveys and has since remained relatively stable. The prevalence of subjects meeting the 12.6 kJ · kg−1 · d−1 (3 kcal · kg−1 · d−1) recommendation increased from 1981 to 1988. Since 1988, the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 recommendation has decreased in 12–14 year old boys and remained relatively stable in the other groups. In 1998, about 45% of males and 35% of females met the 12.6 kJ · kg−1 · d−1 recommendation. In 1998, about 20% of 12–19-year-old males and 12–14-year-old females met the 25.1 kJ · kg−1 · d−1 (6 kcal · kg−1 · d−1) recommendation, while about 10% of 15–19-year-old females met this recommendation. In females, the prevalence of those meeting the 25.1 kJ · kg−1 · d−1 recommendation has remained relatively stable (about 10%) since 1981 except for an increase between 1996 and 1998 in 12–14-year-old girls. In males, a similar pattern, but not as dramatic, of that observed for the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 emerged—that is, an increase between 1981 and 1988 and then a decrease in 12–14-year-old boys and a stable pattern in 15–19-year-old boys. Conclusion: Although self-reported leisure-time physical activity appears to have increased since 1981, a majority of Canadian adolescents do not meet current recommendations for physical activity.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".