Biomechanical analysis of the human femur and tibia under progressive loading conditions inspired by the openings of the Eight Gates of Rock Lee

Abstract

This study presents a biomechanical analysis of the human femur and tibia subjected to progressively increasing loading conditions using the Finite Element Method (FEM). The research was conducted using Autodesk Fusion 360 and was conceptually inspired by the “Eight Inner Gates” of the character Rock Lee, interpreted as progressive increases in muscular activation and axial loading. A body mass of 47.5 kg was considered, corresponding to a baseline physiological load of 466 N. Four loading scenarios were evaluated: normal condition (466 N), Gate 1 (930 N), Gate 5 (1,630 N), and Gate 8 (2,330 N). For the femur, maximum Von Mises stresses ranged from 3.72 MPa to 35.36 MPa, while maximum displacements varied between 0.38 mm and 1.59 mm. In the case of the tibia, Von Mises stresses ranged from 2.13 MPa to 13.07 MPa, with maximum displacements reaching 4.09 mm under the highest loading condition. Across all scenarios, the obtained values remained below the fracture limits commonly reported for cortical bone. However, numerical inconsistencies were identified under intermediate loading conditions, which were attributed to geometric simplifications, mesh characteristics, and boundary conditions adopted in the computational model. The results provide insight into the structural response of the femur and tibia under progressively increasing overload conditions while highlighting the inherent limitations of computational modeling in biomechanical bone analysis.