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Final Program


Final Congress Guide

Clinical Sciences/Health Conditions

400 Section - Within the Margins of Victory: Investigating the Effect of Score-Differential on Head Impact Rates in Canadian Junior High School Football

Tuesday, May 19, 2026
6:00 PM - 7:30 PM PT

    Presenting Author/Autor expositor(s)

  • MP

    Mark P. Pankow, MD, MSc

    Resident Physician
    University of Alberta
    Edmonton, Alberta, Canada

    • Co-Author/Coautor(s)

  • RS

    Reid Syrydiuk, MSc

    Doctural Student
    Michigan Concussion Center, University of Michigan
    Ann Arbor, Michigan, United States

  • AK

    Ashley T. Kolstad, MSc

    Doctural Candidate
    Sport Injury Prevention Research Centre, University of Calgary
    Calgary, Alberta, Canada

  • MM

    Martin Mrazik, MEd, PhD, R.Psych

    Professor, Faculty of Education - Educational Psychology Dept
    University of Alberta
    Edmonton, Alberta, Canada

  • cD

    christopher Dennison, Ph.D., P.Eng

    Associate Professor of Mechanical Engineering
    University of Victoria
    Victoria, British Columbia, Canada

  • BH

    Brent Hagel, PhD

    Professor - Cumming School of Medicine Departments of Pediatrics and Community Health Sciences
    University of Calgary
    Calgary, Alberta, Canada

  • CE

    Carolyn A. Emery, PhD, PT

    Professor of Kinesiology
    Sport Injury Prevention Research Centre, University of Calgary
    Calgary, Alberta, Canada

Objectives :

The high rates of head impacts (HI) observed in tackle football, and the proposed association between repetitive HI and neurodegenerative disease, have heightened interest in HI epidemiology and prevention efforts. The purpose of this study was to investigate HI incidence rates in relation to score-differential, quarter, and down amongst Canadian junior high school football players (aged 15-16 years-old).

Design: In this cross-sectional study, two teams in Calgary, Canada had a total of 28 team-games filmed and analyzed. After no score-difference (tie-game), score-differential was coded in 8-point increments (differentials ³25 were grouped into 4-possession-game) as this represents the maximum amount that can be obtained per offensive-possession. Overall, offensive/defensive (O/D) only, and special-teams (ST) only HI incidence rates (HIIR) per 100-player-plays were calculated (with 95% confidence intervals [95%CI]) to compare HI rates by score-differential (1, 2, 3, 4+possession-game), quarter (1-4), and down (1-3, other [point-after-attempts, kickoffs]).

Results: A total of 8337 HI were coded across 2931 plays (37172 player-plays). The tie-gameoverall HIIR (26.59; 95%CI:24.58, 28.76) was greater than 2-possession-gameoverall (22.40; 95%CI:20.79, 24.13) but did not differ from 1, 3, or 4+possession-gameoverall. When restricted to O/D, the HIIR for tie-gameO/D (28.22; 95%CI:25.66, 31.02) was greater than 1-possessionO/D (23.28; 95%CI:21.40, 25.33) and 2-possession-gamesO/D (22.83; 95%CI:20.95, 24.88) but not 3 or 4+possession-games. First-downO/D HIIR (25.12; 95%CI:23.53, 26.81) was significantly higher than other-downsO/D (12.72;95% CI: 7.57, 21.39). No other significant differences in HIIR were found.

Conclusion:

Significant differences in HIIR were observed between tie-gameoverall and 1-possession-gameoverall as well as between tie-gameO/D and 1, as well as 2-possession-gamesO/D. Notably, HIIR during a tie-game and more lopsided games (3 and 4+possession-games) did not differ. Thus, future investigations might consider developing and evaluating interventions which limit exposure to play when there is a large-score differential to reduce HI incidence during plays unlikely to change the outcome of the game.