Tackle higher or lower? Simulation to evaluate how changing the tackle height would impact the number of concussions and head acceleration events in men’s professional rugby league

OBJECTIVE: To quantify concussion and head acceleration event (HAE) probability in rugby league tackles by tackle height and role and simulate seasonal counts across different tackle height distributions. METHODS: Using a prospective cohort study, data reflecting clinically diagnosed concussions (n=56) and HAEs (n=4632; measured via instrumented mouthguards from 23 081 tackles in 92 players) were collected during the 2023 men's Super League season. Video analysis captured tackle heights for all concussive and accelerometer-measured tackles. Role-specific probabilities were calculated using cumulative link mixed models. Monte Carlo simulation quantified concussions and HAEs across the current tackle-height distribution and three lower tackle-height distributions (weighted redistribution (increased torso tackles), even redistribution (increased torso and lower body tackles) and observed law trial distribution). RESULTS: Ball-carriers experienced the highest concussion and HAE risk from head/neck contact compared with other tackle heights (eg, HAE ≥25 g; 2.7% vs 0.4%-1.1%), while tackler risk was similar. The number of ball-carrier concussions (16 vs 8-9) and HAEs (≥25 g; 830 vs 357-556) decreased with all lower tackle-height distributions. For tacklers, the only meaningful change was an increase in HAEs following the even redistribution of a lower tackle height (≥25 g; 2081 vs 2204). When considering both roles together, only even and weighted lower tackle-height redistributions reduced the total number of lower-to-moderate magnitude HAEs, with no meaningful differences observed for concussions or higher magnitude (≥55 g) HAEs. CONCLUSION: Lowering the tackle height creates a protection paradox, benefiting ball-carriers, while potentially maintaining or increasing the risk for tacklers. Simulated findings may inform policy changes by estimating outcomes and allowing evaluation prior to implementation.