The Influence of Headform Pose on the Blunt Impact Performance of American Football Helmets

The purpose of this research was to evaluate the influence of anthropomorphic test device (ATD) head-neck system pose on the kinematic responses of an ATD donning football helmets during blunt impact tests. Specifically, for two American football helmets, we aimed to determine if identical impact locations but with two different ATD head-neck poses resulted in differences in ATD headform kinematics. Eight Xenith Shadow and eight X2E+ American football helmets were fit to a medium National Operating Committee of Standards for Athletic Equipment (NOCSAE) ATD attached to a male 50th percentile Hybrid III neck. Each helmet was impacted at 6 m/s using a pneumatic linear ram four times at four sites on the helmet. One set (four) of the Shadow and (four) X2E+ helmets were impacted with the ATD head-neck mount system rotated in a manner that sometimes resulted in a flexed looking pose (flexed pose). The other set (four Shadow and four X2E+) were impacted with the ATD head-neck mount system rotated in a manner that sometimes resulted in a lateral bending type pose (lateral bending pose). Dependent measures included the difference (d) between the two poses (flexion-lateral bending) in peak linear acceleration (dPLA), peak angular acceleration (dPAA), and peak angular velocity (dPAV). A significant interaction between helmet and location was observed for dPLA (p < 0.001), dPAA (p < 0.001), and dPAV (p < 0.001). A main effect for helmet was also observed for dPLA (p < 0.001), dPAA (p = 0.025), and dPAV (p < 0.008). The effect of such results within the context of methodologies that rank helmets according to blunt impact performance is discussed.