Estimating lower limb joint kinematics is crucial for assessing movement disorders,optimizing rehabilitation, and monitoring sports performance. Traditional clinical setups require marker-based systems with at least three markers per segment. Wearable IMUs offer an alternative by placing sensors on proximal and distal segments but remain bulky, time-consuming, and costly. This highlights the potential of a minimal sensor configuration. Selecting instrumented segments requires careful consideration. Prioritizing the pelvis, representing center-of-mass dynamics, and the feet, as movement end-effectors, aligns with established methods for estimating spatio-temporal parameters in free-living conditions. This thesis extends previous work on a biomechanical model that estimates joint angles using anthropometric measurements and pelvis/feet orientations and positions.