Comparative Biomechanics of Contemporary Helmet Impact Technologies: Linear and Rotational Head Acceleration During Standardized Collision Testing

Background: Concussion and traumatic brain injury remain major causes of morbidity across contact and collision sports despite continual advances in protective headgear. Linear and rotational head motion are established biomechanical contributors to brain injury and serve as key metrics for evaluating helmet performance. Contemporary helmets employ diverse engineering strategies. including flexible shell architectures, energy-absorbing cellular materials, and sport-specific padding systems, to mitigate impact forces; however, independent comparisons of these approaches remain limited. This study compared the biomechanical performance of two football helmets (Riddell Revolution Speed and Riddell Axiom), a hockey helmet (Bauer RE-AKT 100), and a snow sports helmet incorporating WaveCel® technology (Anon Merak) during standardized impact testing across multiple sites on each helmet.

Methods: A Century Body Opponent Bag (BOB) manikin was instrumented with four embedded linear accelerometers positioned at the left parietal, apex, frontal, and occipital regions, along with a rotational accelerometer at the apex. Each helmet (Riddell Revolution Speed, Riddell Axiom, Anon Merak, Bauer RE-AKT 100) was then independently fitted to the mannikin head for testing. Helmet-to-helmet impacts were generated using a pendulum apparatus with a weighted Xenith X1 helmet to standardize strikes. Impacts were delivered at four respective locations: left parietal, crown, occipital, facemask, with ten trials per condition. Peak linear accelerations and rotational velocities were compared across helmets using two-way ANOVA.

Results: Four helmet designs demonstrated significantly different biomechanical responses across all impact conditions (two-way ANOVA, interaction p < 0.0001 for all strike locations). The flexible-panel Riddell Axiom consistently produced the lowest peak linear accelerations during left parietal, crown, and facemask impacts, with the greatest reductions observed during crown strikes. In contrast, occipital impacts demonstrated substantially greater variability, and no helmet provided uniformly superior protection across all sensor locations. Peak rotational velocity likewise differed significantly among helmet designs, with the football helmets generally producing lower rotational responses than the hockey and snow sport helmets. Performance varied considerably by both impact location and measurement site, indicating that helmet architecture primarily redistributes impact energy rather than providing uniform attenuation throughout the helmet.

Conclusion: Helmet performance was highly location dependent, with distinct engineering strategies demonstrating region-specific biomechanical advantages rather than universal superiority. Flexible-panel football helmet technology most effectively attenuated superior and lateral impacts, whereas no single helmet optimized force reduction across all impact scenarios. These findings underscore the importance of evaluating helmet performance using multidirectional testing and suggest that future helmet development should prioritize region-specific optimization of both linear and rotational head kinematics to better mitigate mechanisms associated with traumatic brain injury.