A MODEL FOR BACK PAIN PREDICTION AND MITIGATION IN MILITARY PILOTS AND VEHICLE OCCUPANTS

P Whitley; A Zhou; G Chen; F Wu; Z Chen; A Przekwas; W Francis; K Sluka; E Park; B Shender

INTRODUCTION: Low back pain while piloting military air vehicles is a significant operational and health problem. Seating, task posture and vibration are major lumbar pain contributors. Asymptomatic pilots start to experience pain and repeated painful episodes lead to pain sensitization and chronic pain. Pilot readiness is reduced and operational availability affected. Modeling can improve crew station design, seating, procedures, and training to enhance pilot operational performance and health. METHODS: Pain events were identified and classified using reported pain sources and mechanisms. Pain mechanism models were identified using nociception and pain theories. Human model complexity requirements were determined using operational helicopter crew station, flight equipment and mission stressors. Model component linkage methods were identified to form an integrated model. The resulting model contained biomechanical, muscle metabolic and pain predictive components. A musculoskeletal back model with a reduced order lumbar functional spinal unit (FSU) model was linked to a muscle metabolic model to predict spinal loading, back muscle activation and fatigue and metabolic species production. Pain prediction methods employed subjective and computational methods. Empirically-derived subjective pain response to muscle metabolites and damage chemical species was combined with Hodgkin-Huxley and Gate Control theory models to predict mechanical strain or metabolic and damage chemical species pain response. RESULTS: A limited scale model was implemented and simulations accomplished. Predictions using a helicopter maneuvering profile comparing slumped to upright seat posture showed predominantly greater muscle activation and force when slumped with low subjective pain scores based on metabolism but below pain threshold computationally. FSU mechanical strains were not large enough to exceed pain threshold. DISCUSSION: A predictive model for pilot back pain has been developed and examined on a limited scale. Further work will expand the concept to a full model capable of occupant back pain assessment and amelioration.

A MODEL FOR BACK PAIN PREDICTION AND MITIGATION IN MILITARY PILOTS AND VEHICLE OCCUPANTS

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