An analysis of tackle-based head acceleration events in elite women’s and men’s rugby union

Abstract

Head acceleration events (HAE) in rugby union are a growing concern due to their potential link to long-term neurodegenerative outcomes. Instrumented mouthguards have been introduced to rugby to quantify HAE severity and identify the mechanisms by which they occur. While early research has identified HAEs to occur at multiple stages of tackle events, few studies have examined technical factors that influence HAE kinematics across all tackle stages. This thesis investigated such factors in elite male and female rugby union.


Study one examined the tackle stages where HAEs occurred and the influence of sex and role in the tackle. HAEs occurred across all tackle stages, with the initial collision being a key concern for male and female tacklers, while the ground impact was a specific concern in female ball carriers.


Study two investigated technical factors of initial collision HAEs, focusing on height and number of tacklers. A trade-off was identified in tackle height, where low tackles exposed tacklers to higher magnitude HAEs whereas high tackles increased risk for ball carriers. Tackles at the torso were associated with the lowest HAE magnitudes across groups. Male tacklers had a significantly higher propensity for higher magnitude HAEs in singular tackler events compared to multiple tackler events, however this pattern was not observed in female players.


Study three and four developed and applied a novel analysis framework for
characterising ground impact (falling and landing) HAEs. Falling technique differed by sex, with the ability to free both hands for landing and maintain neck position appearing more protective of HAEs.


This thesis has contributed novel findings to the literature into tackle-related HAE mechanisms, providing practical and policy insights that can inform future mitigative strategies for HAE exposure. Strategies to explore tackle height and falling/landing technique should be a priority for future research.

Date of Award	Feb 2026
Original language	English
Supervisor	Gregory Tierney (Supervisor) & Chris Bleakley (Supervisor)