Impact of lowering the legal tackle height on tackle behaviour, match events, and suspected injury rates in adolescent female rugby union.

OBJECTIVES

To investigate whether lowering the legal tackle height from below the armpit to below the sternum influenced tackle behaviour, match events, suspected injury and concussion rates, and concussion-related tackle characteristics in adolescent female rugby union.

DESIGN

Case-control video analysis of 49 matches across two seasons, before and after the law change.

METHODS

Tackle behaviour, match events, and suspected concussion characteristics were compared between seasons. Associations between tackle characteristics and suspected concussion were assessed using 37 cases and 222 control tackles.

RESULTS

Head-high tackles were 83% lower (incidence rate ratio 0.17, 95% confidence interval 0.09-0.34) and shoulder-to-armpit tackles 46% lower (incidence rate ratio 0.54, 95% confidence interval 0.40-0.72) after the law change. Offloads, penalties, and open-play kicks increased. Suspected injury rates were 27% lower (rate ratio 0.73, 95% confidence interval 0.53-0.90; p = 0.05). Tackle-related suspected concussion rates were unchanged (incidence rate ratio 0.94, 95% confidence interval 0.49-1.79; p = 0.85). Ruck-related suspected concussions were higher but based on small numbers (incidence rate ratio 9.83, 95% confidence interval 1.26-76.77; p = 0.03). High-intensity head contacts were strongly associated with suspected concussion (odds ratio 52.6, 95% confidence interval 9.2-301.3; p < 0.001), as was lower-leg versus torso or hip head contact (odds ratio 17.22, 95% confidence interval 2.85-103.97; p < 0.001).

CONCLUSIONS

Lowering the legal tackle height changed tackle behaviour and was associated with lower overall suspected injury rates, but tackle-related suspected concussion rates and concussion-related tackle characteristics did not differ. Additional head-safe contact strategies may be required.