A simplified lower extremity model was developed using the geometry from the Global Human Body Models Consortium (GHBMC) 50th percentile male occupant model v4.1.1 (M50) as a base. This simplified model contains 31.4x103 elements and has structures that represent bone (assumed rigid) and soft tissue. This element total is substantially reduced compared to 117.7x103 elements in the original M50 lower extremity. The purpose of this simplified computational model is to output rapid kinematic and kinetic data when detailed structural response or injury prediction data is not required. The development process included evaluating the effects of element size, material properties, and contact definitions on total run time and response. Two simulations were performed to analyze this model; a 4.9 m/s knee bolster impact and a 6.9 m/s lateral knee impact using LS-DYNA R6.1.1. The 40 ms knee bolster impact and lateral knee impact tests required 5 and 7 minutes to run, respectively on 4 cores. The original detailed M50 lower extremity model required 94 and 112 minutes to run the same boundary conditions, on the same hardware, representing a reduction in run time of on average 94%. A quantitative comparison was made by comparing the peak force of the impacts between the two models. This simplified leg model will become a component in a simplified full body model of the seated, 50th percentile male occupant. The significantly reduced run time will be valuable for parametric studies with a full body finite element model.