11.32 Down three: does a reduction in on-field players influence head impacts in Canadian youth tackle football?

• Published in: British journal of sports medicine 2024-01, Vol.58 (Suppl 1), p.A148-A149
• Main Authors: Syrydiuk, Reid, Cairns, Joshua, Pankow, Patrick, Kolstad, Ash, Broglio, Steve, Mrazik, Martin, Emery, Carolyn
• Format: Article
• Language: English
• Subjects: Football; Second Round Abstract Submissions; Teams
• ISSN: 0306-3674; 1473-0480
• DOI: 10.1136/bjsports-2023-concussion.390

ObjectiveTo compare head impact rates in a modified 9-on-9 Bantam (13–15 years old) Canadian football season to a traditional 12-on-12 season using video-analysis.DesignProspective cohort.SettingFootball fields (Calgary, Canada).ParticipantsIn 2020, 384 youth football players (N=18 teams) and in 2021, 500 players (N=12 teams) participated. Video-analysis data was anonymized.Interventions (or Assessment of Risk Factors)Adhering to provincial COVID-19 cohort restrictions, the number of on-field players was reduced to 9-a-side in 2020, returning to 12-a-side in 2021. Independent variables included the number of on-field players, game type (i.e., regular season, playoffs), play type, player position, player role, impact location, and impact object (e.g., helmet, ground).Outcome MeasuresHead impacts (HI) were analyzed using Dartfish video-analysis software. HIs were stratified by team unit (e.g., offensive, defensive, kicking team, receiving team). Using negative binomial regression, HI rates (/100 player-plays and/10 gameplay-minutes) and incidence rate ratios (IRR) were estimated to examine differences between years.Main ResultsNo differences were identified between 9-on-9 and 12-on-12 seasons for offense HI (IRRPlays=0.92, 95% CI; 0.75–1.12, IRRGameMins=0.90, 95% CI; 0.75–1.15) or any other team unit. The offensive team unit, however, experienced a significantly higher HI rate in the 12-on-12 format during playoffs versus the 12-on-12 regular season (IRRPlays=1.33, 95% CI; 1.07–1.65, IRRGameMins=1.26, 95% CI; 1.03–1.56).ConclusionsNo differences in HI were found between the 9-on-9 and 12-on-12 seasons for any team unit. Future research should consider field player-density and combining HI accelerometry, video-analysis, and injury surveillance.