Pivot helmet technology: from head-first impact experiments to the development of a biofidelic testing method

Current commercially available mountain biking helmets are designed to protect against severe head injuries while generally overlooking the potentially serious health consequences of spinal cord and cervical spine injuries (i.e. long-term disability and severe neurological impairment). Downhill mountain biking, due to its intrinsic nature and the high-speed descents, carries a significant risk for cervical spine and spinal cord injuries. One of the typical and most dangerous modes of injury for mountain bikers consists into falling over the handlebars, leading to a head-first impact. In the aforementioned scenario, depending on the spine alignment, the cervical spine can be axially compressed, resulting into high loads that may cause compressive injuries to the vertebrae and the surrounding soft tissues. While research has shown that helmets are an effective preventative measure against head injuries, they have also proven that their use does not significantly reduce the potential for cervical and spinal cord injuries. For this reason, a novel helmet technology has been developed. The Pivot helmet consists of an inner shell connected to an outer shell through a pivot joint. Upon a sufficiently strong head-first impact, the mechanism will allow the inner shell to rotate relatively to the outer shell, thus inducing the movement of the wearer’s head. This flexion-rotation movement of the head moves the spine into a flexion posture, facilitating the neck’s escape from compressive forces and the momentum of following torso, further reducing the axial loads transmitted along the spine, thus reducing the likelihood of severe spinal cord and cervical spine injuries. Here we present a comprehensive description of the design, fabrication and crash testing evaluation of the Pivot technology, together with the critical development of a biofidelic helmet testing method for this novel technology.