Policy change eliminating body checking in non-elite ice hockey leads to a threefold reduction in injury and concussion risk in 11- and 12-year-old players
Bibliographic record
Abstract
BACKGROUND: In ice hockey, body checking is associated with an increased risk of injury. In 2011, provincial policy change disallowed body checking in non-elite Pee Wee (ages 11-12 years) leagues. OBJECTIVE: To compare the risk of injury and concussion between non-elite Pee Wee ice hockey players in leagues where body checking is permitted (2011-12 Alberta, Canada) and leagues where policy change disallowed body checking (2011-12 Ontario, Canada). METHOD: Non-elite Pee Wee players (lower 70%) from Alberta (n=590) and Ontario (n=281) and elite Pee Wee players (upper 30%) from Alberta (n=294) and Ontario (n=166) were recruited to participate in a cohort study. Baseline information, injury and exposure data was collected using validated injury surveillance. RESULTS: Based on multiple Poisson regression analyses (adjusted for clustering by team, exposure hours, year of play, history of injury/concussion, level of play, position and body checking attitude), the incidence rate ratio (IRR) associated with policy allowing body checking was 2.97 (95% CI 1.33 to 6.61) for all game injury and 2.83 (95% CI 1.09 to 7.31) for concussion. There were no differences between provinces in concussion [IRR=1.50 (95% CI 0.84 to 2.68)] or injury risk [IRR=1.22 (95% CI 0.69 to 2.16)] in elite levels of play where both provinces allowed body checking. CONCLUSIONS: The rate of injury and concussion were threefold greater in non-elite Pee Wee ice hockey players in leagues where body checking was permitted. The rate of injury and concussion did not differ between provinces in elite levels, where body checking was allowed.
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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 | 0.004 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 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 | 0.001 |
| 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".