Does tackle height influence offload success in rugby union? Analysis from the 2019 Rugby World Cup

Abstract

Offloads are an effective way of breaking through a defensive line in rugby union. Higher tackle heights are considered an effective strategy to defend against offloads. However, in a bid to reduce head injuries, there is a cultural shift within the rules of the game to tackle lower down on the body. This study used match video analysis of ten games from the 2019 Rugby World Cup to investigate whether tackle height influences offload success for the ball carrier. Each legal tackle was categorised based on tackle height (e.g. shoulder), player body position (e.g. upright), tackle type (e.g. shoulder tackle), tackle direction (e.g. front on) and player position (e.g. tight forwards). For each characteristic, the Odds Ratio (OR) and 95% Confidence Interval (CI) were calculated based on offload success outcome. Tackles at the hip (OR = 1.81, 95% CI 1.10 to 2.96, p = 0.018) and upper leg (OR = 1.94, 95% CI 1.30 to 2.90, p = 0.001) had a greater propensity to result in offload success while tackles at shoulder height reduced offload success (OR = 0.09, 95% CI 0.04 to 0.22, p < 0.001). A bent at the waist tackler against an upright ball carrier had a greater propensity to result in offload success (OR = 1.74, 95% CI 1.19 to 2.54, p = 0.004). Tackling lower increased the chances of offload success for the ball carrier. The cultural shift towards lower tackle heights is likely to result in an increased number of offloads and it is up to players, coaches and defensive systems to be able to adapt to this.