Does changing policy to disallow body checking reduce the risk of concussion in 11 and 12-year-old ice hockey players?
Bibliographic record
Abstract
Objective The objective of this study was to determine if the risk of concussion differed for non-elite Pee Wee ice hockey players (ages 11–12) in leagues where Body Checking (BC) is permitted (Alberta, Canada) versus leagues where policy no longer permits BC (Ontario, Canada). Design Cohort study. Setting Community ice rinks and sport medicine clinics during the 2011/12 season. Participants Forty-four teams from Alberta (n=658) and 32 from Ontario (n=258) participated. Players were from non-elite Pee Wee teams (lower 70% of divisions of play). Assessment of Risk Factors Non-elite Pee Wee ice hockey leagues where BC is permitted (Alberta) compared to leagues where policy no longer permits BC (Ontario). Main Outcome Measurements Players with a suspected concussion were identified by a team therapist or safety designate and referred to a sport medicine physician. Results There were 83 concussions (Incidence Proportion (IP)=12.61 (95% CI; 10.17 to 15.4)) in Alberta and 11 concussions (IP=4.26 (95% CI; 2.15 to 7.5)) in Ontario. The Concussion Risk Ratio was 2.96 (95% CI; 1.6 to 5.46). Overall, 76% of players identified with a concussion were assessed by a physician. Conclusions There was a 3-fold increased risk of concussion in non-elite Pee Wee ice hockey players in leagues where BC is permitted compared to a cohort where BC is no longer permitted. These findings have important implications for further BC policy change to reduce the public health burden of injury and concussion in youth ice hockey. Acknowledgements The University of Calgary Sport Injury Prevention Research Centre is one of the International Research Centres for Prevention of Injury and Protection of Athlete Health supported by the International Olympic Committee. We also acknowledge the support of Max Bell Foundation, Alberta Innovates Health Solutions and the Alberta Children's Hospital Institute for Child and Maternal Health (Alberta Children's Hospital Foundation).
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".