Can tackle height influence head injury assessment risk in elite rugby union?

Objectives: Tackle height laws are an area of controversy in rugby union. It is reported that the tackler is at most risk of a Head Injury Assessment (HIA). Therefore, the aim of this study was to use match video evidence of tackles in elite level rugby union to examine the effect of tackle heights on HIA risk for the tackler. Design: Qualitative observational case-control study. Methods: Each HIA (n = 74) and control tackle (n = 965) was categorised based on tackle direction (front- or side-on), tackle type (arm, shoulder or smother) and tackle height (upper trunk, mid-trunk, lower trunk, upper leg or lower leg). The Relative Risk (RR), 95% Confidence Interval (CI) and probability (p) values were calculated for each tackle height. Results: Intended primary contact at the upper trunk of the ball carrier had a greater propensity to result in a HIA for the tackler for front-on upper body shoulder tackles (RR = 1.48; 95%CI = 1.16-1.90; p < 0.01) and side-on upper body smother tackles (RR = 2.30; 95%CI = 1.82-2.92; p < 0.01). Intended primary contact at the upper leg of the ball carrier had a greater propensity to result in a HIA for the tackler for front-on (RR = 2.60; 95%CI = 1.70-3.97; p < 0.01) and side-on (RR = 3.34; 95%CI = 1.65-6.79; p < 0.01) lower body shoulder tackles. Conclusions: To reduce tackler HIA risk, the results suggest tackling below the upper trunk for upper body tackles. The results also suggest tackling at the lower trunk for lower body tackles and avoiding the upper legs. Prevention strategies should place emphasis on tackling lower risk body regions such as the mid- and lower trunk. (C) 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.