Numerical models of Hybrid III had been widely used to study the effect of underbody blast loading on lower extremities. These models had been primarily validated for automotive loading conditions of shorter magnitude in longer time span which are different than typical blast loading conditions of higher magnitude of shorter duration. Therefore, additional strain rate dependent material models were used to validate lower extremity of LSTC Hybrid III model for such loading conditions. Current study focuses on analyzing the mitigating effect of combat boots in injury responses with the help of validated LSTC Hybrid III model. Numerical simulations were run for various impactor speeds using validated LSTC Hybrid III model without any boot (bare foot) and with combat boot. Results from the current study show that the stiffness response of boot material plays a major role in validating the numerical model under such blast loading conditions which may lead to different biomechanical responses of Hybrid III as seen in automobile crashes. Therefore, it is worth of validating the model first in barefoot conditions and then, further incorporation of boot like structure to study their blast mitigation capabilities. Results from the current study will be used in studies for whole body model validation and further, providing the guidelines for future cadaveric setups.