Abstract
Purpose This study evaluates the impact-attenuation of two softshell headgear models, GameBreaker-Pro and GameBreaker-Prototype, in controlled drop tests. These models were selected to assess the effect of thickness, given the 12 mm thickness constraint specified under World Rugby Law 4 Trial regulations for which limited justification exists. Methods Drop tests were conducted using a Hybrid III headform and neck, from heights of 15, 30, 45, and 60 cm onto a flat Modular Elastomer Programmer (MEP) surface. Impacts were delivered across five orientations; forehead, front boss, rear boss, rear, and side, to simulate a range of plausible on-field rugby impact scenarios. Peak linear acceleration (PLA), peak rotational acceleration (PRA), and peak rotational velocity (PRV) were measured across four headgear conditions: GameBreaker-Pro, GameBreaker-Prototype, NPro (World Rugby Law 4 Trial approved), and a no-headgear baseline. Results All headgear models demonstrated reductions in impact kinematics relative to the no-headgear baseline. GameBreaker-Pro yielded the highest composite reductions (peak accelerations across all orientations), lowering PLA by 32.3% and PRA by 43.4%, followed closely by GameBreaker-Prototype with reductions of 30.4% and 42.2%, respectively. Both GameBreaker models showed consistent attenuation across drop heights and orientations, with particularly strong performance in the side (reductions of 43.5% and 37.1% in PLA, 59.1% and 54.3% in PRA). Conclusion These findings demonstrate that softshell headgear can reduce head impact severity across diverse conditions. This underscores the need for ongoing refinement of headgear design and regulatory standards to better safeguard athletes from repeated intensive head impacts.