PW 1987 Effectiveness of body checking policy change in youth ice hockey to reduce the risk of injury
Bibliographic record
Abstract
<h3>Background</h3> Ice hockey is Canada’s most popular winter sport. We have previously demonstrated that injury and concussion risk is reduced >60% in 11–12 year-old players where body checking was disallowed in games nationally in Canada in 2013. Objective: To evaluate the risk of injury and concussion associated with policy change disallowing body checking in games in non-elite Bantam (ages 13–14) ice hockey leagues, compared to body checking leagues. <h3>Methods</h3> This is a cohort study. Bantam players were recruited from non-elite Bantam teams where policy allowed body checking and following policy change where policy disallowed body checking (2014–2016). A validated injury surveillance system was used to collect preseason, exposure, and injury data. All ice hockey injuries were identified by a team safety designate. Any player with a suspected concussion was referred to a study sport medicine physician. Multivariable Poisson regression analyses controlled for relative age, previous injury, and clustering by team (offset by exposure hours). <h3>Findings</h3> Forty-nine body checking teams (608 players) and 33 teams non-body checking teams (396 players) participated. There were 123 game injuries [incidence rate (IR)=7.61/1000 hours] and 53 game concussions (IR=3.28/1000 hours). After policy change, there were 27 game injuries (IR=3.19/1000 hours) and 14 game concussions (IR=1.65/hours). Policy disallowing body checking was associated with a reduced rate of all injury [incidence rate ratio (IRR)=0.36 (95% CI; 0.21–0.61)], injury (time-loss >7 days) [IRR=0.35 (95% CI; 0.2–0.62)], concussion [IRR=0.43 (95% CI; 0.21–0.88)], and concussion (time-loss >10 days) [IRR=0.4 (95% CI; 0.18–0.87)]. <h3>Conclusion</h3> Policy change disallowing body checking in non-elite Bantam ice hockey resulted in a 64% reduction in injury and 57% reduction in concussion rate. <h3>Policy implications</h3> These findings have important implications for sport policy change informing a reduction in the public health burden of injury.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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".