216 Who’s keeping score? The effect of a score differential based running time rule on head impact rates in Canadian high school tackle football
Bibliographic record
Abstract
<h3>Background</h3> Due to postulated associated long-term health issues in athletes, concussions and head impacts are of concern in tackle football. Football Canada mandated a game clock running-time rule (RTR) in the event of a second-half 35-point difference in games, citing player safety as the main rationale. <h3>Objective</h3> To examine the effectiveness of RTR on reducing game-related head impact rates in Canadian high school football using video analysis. <h3>Design</h3> Cross-sectional. <h3>Setting</h3> Calgary, Canada. <h3>Participants</h3> Players on two junior division high school teams (ages 15–16) in Calgary, Alberta were included. Fourteen games from the 2019 season (Team A: n=8, Team B: n=6) were videotaped for analyses. <h3>Assessment of Risk Factors</h3> Traditionally, the clock stops between plays until the referee signals for the clock to resume. With RTR the clock continues (except during exceptional circumstances such as injury, scores, or timeouts) in the event of a point differential of 35 points or greater in the second half of a game. <h3>Main Outcome Measurements</h3> Head impacts were reported as incidence rates (IR) [# head impacts/100 player-game-minutes (PGM) (95% confidence intervals (95% CI)]. Incidence rate ratios (IRR), offset for PGM, adjusted for game outcome (e.g., win, loss) and clustering by team game were used to compare score differential in games with and without running-time (≥35 points vs. <35 points) by team unit (e.g., offense, defense). <h3>Results</h3> RTR games yielded 24% fewer plays than non-RTR games (IRR: 0.76, 95% CI: 0.68, 0.84). Head impact IR in RTR games were lower than non-RTR games for offensive units (IRR:0.80; 95% CI:0.68, 0.95) and defensive units (IRR:0.76; 95% CI:0.59, 0.99). There were no differences in special teams units. <h3>Conclusions</h3> RTR reduced game-related head impact IRs in this cohort for both offensive and defensive units. Sport governing bodies should consider the potential effect of RTR on injury and concussion rates at the youth level.
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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 | 0.002 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.003 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".