Tackle behaviour trial lowers concussion and overall injury rates: A seven-season prospective study in adult men's, women's and schoolboy rugby union

Objectives: To determine the impact of lowering the legal tackle height from the armpit to the base of the sternum on tackle-event match concussion, all tackle-event and overall match injury rates across adult community (men and women) and schoolboy rugby union competitions in Ireland. Design: Prospective observational study comparing seasons prior to the law change (control seasons: 2017/18–2022/23) with seasons post law change (intervention seasons: 2023/24–2024/25). Methods: Match injury and exposure data were collected from community adult men's, adult women's and schoolboy teams participating in community rugby competitions across seven and five seasons for adult and schoolboy competitions respectively. Incidence rates per 1000 match hours and incidence rate ratios with 95% confidence intervals (CIs) were calculated. Results: Two hundred and thirty-nine teams participated, accounting for 8805 player-seasons. Significant reductions were observed in tackle-event concussion rates for both adult men (IRR = 0.62, 95% CI 0.47–0.82) and adult women (IRR = 0.37, 95% CI 0.14–0.96) and tackle-event injury incidence rates (adult men: IRR = 0.79, 95% CI 0.71–0.89; adult women: IRR = 0.66, 95% CI 0.49–0.87). Non-significant increases in the frequency and incidence rates of match concussion amongst schoolboys were also observed. Across all three cohorts, match injury incidence rates decreased during the intervention seasons by 18% in adult men's competitions (IRR = 0.82, 95% CI 0.75–0.89), 30% in adult women (IRR = 0.70, 95% CI 0.57–0.88) and 19% in schoolboys (IRR = 0.81, 95% CI 0.69–0.95) compared to the control seasons. Conclusions: This is the first study exploring the impact of a lowered tackle height in rugby union to report significantly positive results across the adult game. Subsequent work should aim to understand the schoolboy context to inform further targeted interventions.