Lower Extremity Biomechanical Response of Female and Male Post-Mortem Human Surrogates to High-Rate Vertical Loading During Simulated Under-Body Blast Events

During an under-body blast (UBB) event, an improvised explosive device (IED) delivers a high-energy blast beneath a military vehicle, exposing mounted Warfighters to considerable risk of severe lower extremity injuries. Loftis and Gillich (2014) determined that the lower leg and ankle region is the most common body region to sustain skeletal injury in military mounted combat events, comprising twenty-one percent of cases reported in the Joint Trauma Analysis and Prevention of Injuries in Combat (JTAPIC) database between 2010 and 2012. Injuries of the lower extremity are not always life-threatening. However, from a survivability standpoint, these injuries may affect the ability of the Warfighter to self-extricate and ambulate in the immediate aftermath of an UBB event. In addition, lower extremity injuries can lead to long term health complications and reduced quality of life (Dischinger et al., 2004). While some comparisons can be drawn from the study of civilian automotive crashes; the impact level, rate, location, and directions in UBB are fundamentally different for the lower extremity. Therefore, substantial research efforts to characterize and assess injuries unique to UBB are essential. The Warrior Injury Assessment Manikin (WIAMan), the Tech Demonstrator version of which was introduced by Pietsch et al. (2016), is the only anthropomorphic test device (ATD) designed to evaluate injury patterns in UBB conditions. However, there are no known injury assessment tools for the female Warfighter at this time. The overarching goal of this research effort is to determine the origin of potential differences in the response of females and males in UBB conditions. The results of this work contribute to the body of research concerning high-rate axial loading of the lower extremity and form the first detailed biomechanical account of UBB effects on female PMHS. This work will inform future decisions regarding the requirements for a valid injury assessment capability for female Warfighters in the UBB environment and the subsequent research needed to support those requirements. Ultimately, advancements can be made in modeling and simulation capabilities, injury assessment criteria, test methodologies, and design approaches for safer military ground vehicles and personal protective equipment (PPE). Improvements in these technologies will reduce morbidity and mortality rates among the U.S. Warfighter population, both male and female.