This study has explored the potential of developing and optimizing a prosthetic running blade incorporating a lattice core sandwich structure design for lightweight and high-performance applications. Using SolidWorks, the prosthetic incorporates a lattice core construction that was designed to achieve strength and reduced weight. A 3-dimensional Computed Aided Design (CAD) model is subsequently exported to ANSYS Workbench. Finite Element Analysis (FEA) is then carried out to evaluate the structural integrity and performance under a load of 2400 N, simulating the maximum force exerted by an 80 kg athlete during running. Carbon fiber and titanium were selected for their superior mechanical properties, by ensuring minimal deformation at 26.47 mm and a safety factor above 1. The FEA results have demonstrated that the prosthetic running blade can withstand the applied load, maintain low deformation, and ensure durability, meeting the necessary performance standards of the European Union Medical Device Regulation (EU MDR). The findings also highlighted that the achievement of a lightweight design through mass reduction by 63.54%, enhancing overall efficiency and adaptability, were proven critical for competitive sports performance. Additionally, the prosthetic running blade can be manufactured at a lower cost using 3D Printing Technology, offering enhanced customizable options for users. This cost-effective manufacturing process broadens the accessibility and personalization of sports prosthetics. The successful application of a lattice core sandwich structure in the prosthetic running blade provides a lightweight and robust solution, opening new avenues for advancements in sports prosthetics. The implications of this study are profound, extending to improving the quality of life and athletic capabilities of individuals with lower limb amputations, offering them enhanced opportunities to participate in high-intensity sports activities.