Comparing two proposed protocols to test the oblique response of cycling helmets to fall impacts

In cycling, oblique head impacts from a fall cause rotational motion of a cyclist's head and it is rotational kinematics that are most commonly associated with mild and severe brain injuries. This study aims to compare the head kinematics and brain strain response between two oblique test protocols for simulating fall impact events in cycling. (1) The Angular Launched Impact (ALI) protocol simulates a head impact for realistic and typical falling events in cycling such as falling over the bicycle handle bars or laterally falling, and (2) EN13087-11 is a currently proposed standard test that simulates a head impact from a vertical fall onto an angled surface. EN13087-11 reported greater rotational head kinematics and brain tissue strain than occurs in the more frequent and realistic falling events simulated by the ALI. Differences in response are attributed to the different vector of impact forces associated with the ALI and EN13087-11. When considering how best to test a helmet under oblique impact conditions, it is recommended that a certification test should closely mimic real-world kinematics of cycling accidents.