University of Waterloo, Waterloo, ON, USA.
University of Massachusetts Amherst, Amhers, MA, USA.
Hum Factors. 2024 Feb;66(2):363-376. doi: 10.1177/00187208221090689. Epub 2022 Apr 26.
Chronic Neck Pain (CNP) among rotary-wing aircrew is thought to stem from night vision goggles (NVG) and counterweight (CW) systems which displace the centre of mass of the head. This investigation aimed to quantify the loads acting on the neck as a function of movement magnitude (MM), helmet conditions, and movement axes in rapid movements.
Cervical spine kinematics during rapid head repositioning tasks for flexion-extension (FE) and axial rotation (AR) movements were measured from 15 males and 15 females. Participants moved in either a 35° (Near MM) or 70° arc (Far MM), while donning a helmet, helmet with NVG, helmet with NVG and a typical CW, and a CW Liner (CWL). Measured EMG from three muscles bilaterally and used to drive a biomechanical model to quantify the compression and shear acting at the C5-C6 joint.
In AR, the NVGs were associated with the largest compression magnitudes, 252 (24) N. CW conditions decreased the maximum compression to 249 (53) N. For FE, the compression was 340 N for the Far MM trials and 246 N for Near MMs. Changing the helmet configuration only modestly influenced these magnitudes in FE.
Every 30° of MM increased compression by 57 to 105 N. The reduction of the moment of inertia by 16% in the CWL did not reduce reaction forces. Joint loads scaled proportionately with head-supported weight by a factor of 2.05. The magnitudes of loads suggest a cumulative loading pathway for CNP development.
旋翼机机组人员的慢性颈部疼痛（CNP）被认为源于夜视镜（NVG）和配重（CW）系统，这些系统会改变头部的质心位置。本研究旨在量化头部快速运动时颈部所受的负荷与运动幅度（MM）、头盔状态和运动轴之间的关系。
从 15 名男性和 15 名女性中测量了颈椎在快速头部复位任务中进行屈伸（FE）和轴向旋转（AR）运动时的运动学。参与者在戴头盔、头盔配 NVG、头盔配 NVG 和典型 CW 以及 CW 衬垫（CWL）的情况下，以 35°（近 MM）或 70°（远 MM）的弧进行运动。双侧 3 块肌肉的肌电图用于驱动生物力学模型，以量化 C5-C6 关节处的压缩和剪切力。
在 AR 中，NVG 与最大压缩力 252（24）N 相关。CW 条件将最大压缩力降低至 249（53）N。对于 FE，远 MM 试验的压缩力为 340 N，近 MM 的压缩力为 246 N。FE 中改变头盔配置仅适度影响这些幅度。
每增加 30°的 MM 会增加 57 到 105 N 的压缩力。CWL 中转动惯量减少 16%并没有降低反作用力。关节负荷与头部支撑重量成比例增加，比例系数为 2.05。这些负荷的大小表明了 CNP 发展的累积负荷途径。
