Neck and Shoulder Muscle Fatigue in High Performance Aircrafts Pilots: A Case Study

Abstract

Neck injury because of exposure to increased Gz acceleration is a well-known problem in literature and has been studied by several air forces. Jet pilots reported a high prevalence of neck pain if compared to the general population. Some interventions focused on aircraft design and personal protective equipment, while others were directed toward pilot training. In literature, various primary prevention strategies are reported such as preflight warm-up, in-flight techniques, muscle resistance training, neck-specific training regimens and techniques. However, results from all of these studies showed discordant results. The aim of the study is to investigate muscle fatigue of left and right sternocleidomastoid, upper trapezius and middle trapezius by means of the Joint Analysis of the Spectrum and Amplitude of sEMG which analyzes the temporal changes in the amplitude of the sEMG signal, evaluated using the Root Mean Square and the frequency of the sEMG signal, expressed as Median Frequency. In this study, we investigated a fighter pilot before and soon after a diurnal flight, therefore we did not take into account night vision goggles and counterweight usage. We found that the fatigue indexes calculated from the neck and shoulder muscles are quite sensitive in detecting jet pilots’ fatigue. More in detail, it can be observed that as far as the right side is concerned, soon after the flight all the fatigue events of the JASA plot fall in the fatigue quadrant. The results of this study strengthen the suggestion aimed previously at helicopter pilots, to incorporate neck and shoulder specific training in the list of operational duties. These myoelectric fatigue indicators may be useful to evaluate neck and shoulder muscle engagement, and they may be helpful to define physical exercise limits. In conclusion, this study showed that it is possible to obtain more detailed information about neck stress through sEMG fatigue parameters, and provide an insight for helmet and seat design improvements. The reduction in some of the causative factors for neck pain may help to increase the career longevity of jet pilots, reducing the work compensation cost and the costs associated with training new aircrew.