Harrison Michael F, Forde Kelsey A, Albert Wayne J, Croll James C, Neary J Patrick
Departments of Emergency Medicine and Internal Medicine, Henry Ford Hospital, Detroit MI, USA.
Aerosp Med Hum Perform. 2016 Jan;87(1):48-53. doi: 10.3357/AMHP.4301.2016.
Night vision goggles (NVG) are linked to increased neck muscle activation and pain. Counterweights (NVGcw) are hypothesized to mitigate these effects. The purpose of this study was to investigate the muscular response to varying helmet loads and postures.
Volunteering from a representative squadron were 16 male helicopter aviators (pilots, N = 9; flight engineers, N = 7). Subjects performed head movements to assume nine different postures (three directions: left, center, and right, at three different levels: down, level, and up) with four different head loads (no helmet; helmet only; NVG; and NVGcw) in randomized order. Subjects were provided real time visual guidance and feedback while assuming the appropriate posture in a cockpit seat in a laboratory setting. Neck muscle activation was assessed with electromyography (EMG) of four different muscle groups, bilaterally, including the sternocleidomastoid, splenius capitis, and mid and lower trapezius.
Two- to fourfold increases in muscle activation were observed in postures to the left (down, level, and up) while subjects wore either the NVG or NVGcw as compared to the baseline of no helmet. This was most prevalent in smaller muscle groups (i.e., the sternocleidomastoid and splenius capitis) as compared to larger muscle groups (i.e., the mid and lower trapezius).
The use of NVGcw did not decrease neck muscle activity as compared to NVG only, particularly when the head posture moved the field of view below the horizon. This suggests interventions to decrease neck muscle activity and fatigue in military helicopter aircrew using NVG should focus on task specific guidelines with respect to countermeasures.
夜视镜（NVG）与颈部肌肉激活增加和疼痛有关。据推测，配重（NVGcw）可减轻这些影响。本研究的目的是调查不同头盔负荷和姿势下的肌肉反应。
从一个具有代表性的中队中招募了16名男性直升机飞行员（飞行员，N = 9；飞行工程师，N = 7）。受试者进行头部运动，以随机顺序呈现四种不同的头部负荷（不戴头盔；仅戴头盔；戴夜视镜；戴带配重的夜视镜），采取九种不同姿势（三个方向：左、中、右，三个不同高度：向下、水平、向上）。在实验室环境中，受试者坐在驾驶舱座椅上采取适当姿势时，会得到实时视觉指导和反馈。通过对双侧四块不同肌肉群（包括胸锁乳突肌、头夹肌以及中斜方肌和下斜方肌）进行肌电图（EMG）评估来测定颈部肌肉激活情况。
与不戴头盔的基线相比，受试者佩戴夜视镜或带配重的夜视镜时，向左（向下、水平和向上）姿势下的肌肉激活增加了两到四倍。与较大的肌肉群（即中斜方肌和下斜方肌）相比，这种情况在较小的肌肉群（即胸锁乳突肌和头夹肌）中最为普遍。
与仅佩戴夜视镜相比，使用带配重的夜视镜并没有降低颈部肌肉活动，特别是当头部姿势将视野移至地平线以下时。这表明，针对使用夜视镜的军事直升机机组人员，减少颈部肌肉活动和疲劳的干预措施应侧重于针对对策的特定任务指南。
