Neck Muscle Strain in Air Force Pilots Wearing Night Vision Goggles

INTRODUCTION: Flight-induced neck pain is common in high performance jet pilots, with incidents frequently attributed to high G, flight maneuvers. The additional load of helmet-mounted night vision goggles (NVG) is believed to increase the risk, possibly from neck muscle strain in counteracting muscles. Hence, the aim was to investigate the effect of NVG on neck muscle strain as well as on the activity level distribution through a simulated flight session in air force pilots. METHODS: In this post hoc randomized crossover trial, four senior air force pilots each completed two identical 1.5-h dynamic flight simulations in a human centrifuge: one with a standard helmet and NVG, and one with a standard helmet only. Simulations included repeated exposure to 3-7 G(z), during which neck muscle activity was recorded bilaterally from the anterior neck, the upper and lower posterior neck, and the upper shoulders. The number of muscle activities surpassing 50% of maximum voluntary electrical activity (MVE) and total time of activity at each MVE percentile were compared between NVG and control flights. RESULTS: There was no overall effect in number of neck strain activities between NVG and control flights; however, significantly more activities emerged in the anterior neck. In addition, MVE percentile data showed a tendency of higher activity in the lower posterior neck during NVG flights. CONCLUSIONS: The results showed that the additional load of helmet-mounted NVG increases neck muscle strain in anterior stabilizing muscles, indicating that the inertia of head-worn NVG elevates the risk of flight-related neck pain.