Sanctioned illegal high tackles significantly increase concussion risk to both tacklers and ball carriers in elite men's Rugby Union.

Objectives: Tackles making contact above the sternum increase concussion and head injury assessment (HIA) risk in Rugby Union. The sport has introduced harsher sanctions to change tackler behaviours to reduce this risk. This increased high tackle sanction numbers, though it is unknown whether sanction severity is associated with injury risk.

Methods: The sanction decision made by match officials for tackles resulting in 157 HIA1 removals, of which 91 were confirmed concussions, was evaluated. The propensity of sanction types, ranging from no foul play to red card, was compared after calculating concussion and HIA1 numbers per 1000 tackles of each sanction, using total tackle number of each sanction type from one season of two elite professional competitions.

Results: HIA1 removal and concussion risk increased as sanction severity increased. Red-carded tackles were 271.5 (95% CI 143.8 to 512.6) times more likely to result in concussions than legal tackles. Tacklers and ball carriers were more likely to experience concussions from sanctioned high tackles, with tackler risk 28.5 (95% CI 13.5 to 59.9) times higher for sanctioned high tackles compared with legal tackles, and ball carrier risk elevated 133.7-fold (95% CI 65.5 to 272.8) after sanctioned high tackles.

Conclusion: Sanctioned high tackles significantly increase concussion and HIA1 risk to both tacklers and ball carriers. Current decision-making frameworks that guide sanction decisions do identify tackle behaviours that elevate clinical risk. Both tacklers and ball carriers would be less likely to experience concussions and head injuries if the frequency of illegal high tackles is decreased.