Neck muscle activity during simulated in-flight static neck postures and helmet mounted equipment

Abstract

BACKGROUND: Static postures and heavy helmets elicit neck pain in many aircraft personnel during or after flight. Helmet-mounted equipment can further increase neck loading and injury risk. OBJECTIVE: To quantify neck muscle activity changes as a function of helmet configuration and static neck pos tures. METHODS: Eight male participants participated. Neck surface EMG was measured bilaterally in each combination of 7 neck postures (neutral, flexed, extended, twisted, laterally flexed, and two combination postures) and 5 helmet-mounted equipment configurations (combinations of a helicopter helmet, night-vision goggles (NVG), and a 600 g counterweight (CW)). RESULTS: Helmet configuration alone did not influence activity for any muscle. Peak muscle activity was less than 5% of maximum voluntary exertion for most trials. The highest neck extensor activity occurred when wearing the helmet with CW and NVG engaged, while the lowest activity occurred in the same setup but NVG in a disengaged position, and helmet configuration effects varied by target posture. Muscle activity tended to be greatest in extension and combination movements for the lateral muscles and in flexion and flexion with rotation for the neck extensors. CONCLUSION: Neck posture influenced neck muscular demands more than the configuration of helmet-mounted equipment. As such, cockpit layout may play a primary role in mitigating neck injury risk factors.