The effect of helmet mass and aircraft acceleration on cervical spine loads during typical fast jet aircraft pilot head motions

Abstract

ObjectivesGravitational Force (Gz), head motion, and helmet mass are associated with neck pain in high performance aircraft pilots. Few studies have quantified neck kinetics (intersegmental neck moments) during aerial combat manoeuvres. DesignCross-sectional. MethodsWe quantified net joint moments between the skull and C1, and C6–7 during typical flight related headchecks using the Musculoskeletal Model for the Analysis of Spinal Injuries (MASI). We measured the influence of pilot-specific helmets and Gz on joint moments. Nineteen fighter pilots performed four head checks (check6 left, check6 right, extension hold and extension scan) under two helmet conditions. Motion data were transferred to OpenSim where joint moments were calculated at 1G to 9G. Net joint moments were compared across helmet conditions, Gz and headchecks. ResultsThe Joint Helmet Mounted Cueing System (JHMCS) resulted in higher moments at each segment- by a factor of 1.25 per unit of Gz, at C1, and by a factor of 1.08 per unit of Gz for C7. ExtensionScan and Check6Left were associated with the highest peak (96.13 Nm and 92.56 Nm). ExtensionScan and ExtensionHold accrued the highest mean cumulative loads at C7 at 9Gz (607.35 Nm.sec/motion, 362.99 Nm.sec/motion respectively). Asymmetries were observed between the Left and Right Check6 motions. High variability was evident between and within pilots. ConclusionsThe MASI model has been successfully applied to quantify intersegmental neck joint moments for typical headchecks that are performed during combat flight manoeuvres. In future, data derived from this model may inform conditioning, rehabilitative and preventative interventions to reduce neck pain in fast jet pilots.