title: Angular Impact Mitigation system for bicycle helmets to reduce head acceleration and risk of traumatic brain injury.
abstract: Angular acceleration of the head is a known cause of traumatic brain injury (TBI), but contemporary bicycle helmets lack dedicated mechanisms to mitigate angular acceleration. A novel Angular Impact Mitigation (AIM) system for bicycle helmets has been developed that employs an elastically suspended aluminum honeycomb liner to absorb linear acceleration in normal impacts as well as angular acceleration in oblique impacts. This study tested bicycle helmets with and without AIM technology to comparatively assess impact mitigation. Normal impact tests were performed to measure linear head acceleration. Oblique impact tests were performed to measure angular head acceleration and neck loading. Furthermore, acceleration histories of oblique impacts were analyzed in a computational head model to predict the resulting risk of TBI in the form of concussion and diffuse axonal injury (DAI). Compared to standard helmets, AIM helmets resulted in a 14% reduction in peak linear acceleration (p<0.001), a 34% reduction in peak angular acceleration (p<0.001), and a 22-32% reduction in neck loading (p<0.001). Computational results predicted that AIM helmets reduced the risk of concussion and DAI by 27% and 44%, respectively. In conclusion, these results demonstrated that AIM technology could effectively improve impact mitigation compared to a contemporary expanded polystyrene-based bicycle helmet, and may enhance prevention of bicycle-related TBI. Further research is required.
authors.affiliation: Biomechanics Laboratory, Legacy Research Institute, Portland, OR 97232, United States.
authors.forename: Kirk
authors.initials: K
authors.lastname: Hansen
authors.forename: Nathan
authors.initials: N
authors.lastname: Dau
authors.forename: Florian
authors.initials: F
authors.lastname: Feist
authors.forename: Caroline
authors.initials: C
authors.lastname: Deck
authors.forename: Rémy
authors.initials: R
authors.lastname: Willinger
authors.forename: Steven M
authors.initials: SM
authors.lastname: Madey
authors.forename: Michael
authors.initials: M
authors.lastname: Bottlang
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic; D001642:Bicycling / Q000293:injuries* / Q000502:physiology; D001696:Biomechanical Phenomena; D001924:Brain Concussion / Q000517:prevention & control*; D001930:Brain Injuries / Q000517:prevention & control; D020833:Diffuse Axonal Injury / Q000517:prevention & control*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006260:Head Protective Devices / Q000592:standards*; D006801:Humans; D008348:Manikins; D008954:Models, Biological
keywords: Bicycle; Concussion; Helmet; Impact mitigation; Rotational acceleration; Traumatic brain injury