Butz Robert C, Knowles Brooklynn M, Newman James A, Dennison Christopher R
Biomedical Instrumentation Laboratory, University of Alberta, Edmonton, AB, Canada; Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada.
Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada.
J Biomech. 2015 Nov 5;48(14):3816-24. doi: 10.1016/j.jbiomech.2015.09.032. Epub 2015 Oct 8.
Competitive cycling is a popular activity in North America for which injuries to the head account for the majority of hospitalizations and fatalities. In cycling, use of helmet accessories (e.g. cameras) has become widespread. As a consequence, standards organizations and the popular media are discussing the role these accessories could play in altering helmet efficacy and head injury risk. We conducted impacts to a helmeted anthropomorphic headform, with and without camera accessories, at speeds of 4m/s and 6m/s, and measured head accelerations, forces on the head-form skull, and used the Simulated Injury Monitor to estimate brain tissue strain. The presence of the camera reduced peak linear head acceleration (51% - 4m/s impacts, 61% - 6m/s, p<0.05). Skull fracture risk based on kinematics was always less than 1%. For 4m/s impacts, peak angular accelerations were lower (47%, p<0.05), as were peak angular velocities (14%) with the velocity effect approaching significance (p=0.06), with the camera accessory. For 6m/s impacts, accelerations were on average higher (5%, p>0.05) as were velocities (77%, p<0.05). Skull forces were never greater than 443.2N, well below forces associated with fracture. Brain tissue strain, the cumulative strain damage measure at 25% (CSDM-25), was lower (56%, p<0.05) in 4m/s but higher (125%, p>0.05) in 6m/s impacts with the camera accessory. Based on CSDM-25 for 4m/s tests, the risk of severe concussion was reduced (p<0.05) from 25% (no camera) to 7% (camera). For 6m/s tests, risks were on average increased (p>0.05) from 18% (no camera) to 58% (camera).
竞技自行车运动在北美是一项广受欢迎的活动，其中头部受伤占住院和死亡病例的大多数。在自行车运动中，头盔配件（如摄像头）的使用已变得十分普遍。因此，标准组织和大众媒体正在讨论这些配件在改变头盔功效和头部受伤风险方面可能发挥的作用。我们以4米/秒和6米/秒的速度，对佩戴和未佩戴摄像头配件的头盔式人体头部模型进行了撞击测试，并测量了头部加速度、头部模型颅骨上的力，还使用模拟损伤监测器来估计脑组织应变。摄像头的存在降低了头部线性加速度峰值（4米/秒撞击时降低51%，6米/秒撞击时降低61%，p<0.05）。基于运动学的颅骨骨折风险始终低于1%。对于4米/秒的撞击，峰值角加速度较低（降低47%，p<0.05），峰值角速度也较低（降低14%），速度效应接近显著水平（p=0.06），这是在有摄像头配件的情况下。对于6米/秒的撞击，加速度平均更高（升高5%，p>0.05），速度也更高（升高77%，p<0.05）。颅骨受力从未超过443.2牛，远低于与骨折相关的力。脑组织应变，即25%时的累积应变损伤测量值（CSDM-25），在4米/秒撞击时有摄像头配件时较低（降低56%，p<0.05），但在6米/秒撞击时较高（升高125%，p>0.05）。基于4米/秒测试的CSDM-25，严重脑震荡风险从25%（无摄像头）降低到7%（有摄像头）（p<0.05）。对于6米/秒测试，风险平均从18%（无摄像头）增加到58%（有摄像头）（p>0.05）。
