The latest Euro NCAP Vulnerable Road Users Assessment Protocol (v11.3) introduces the advanced Pedestrian Legform Impactor (aPLI) to reduce the risk of lower extremity injury to pedestrians in a vehicle collision. The addition of femur injury criteria and the added simplified upper body mass, compared to its predecessor –the FlexPLI–, allows a more comprehensive assessment of passive pedestrian safety. However, this presents new challenges for vehicle manufacturers as these additions must be accounted for. We perform four sensitivity analyses at two test positions (centre and at the headlight) on two vehicles (compact car and SUV). Thereby, we investigate five design parameters that represent the main front-end components and identify that the vehicle type determines the sensitive design parameters significantly. Furthermore, we show that the influence of the lower stiffener and energy-absorbing foam diminishes compared to older legform impactors, while that of the bonnet increases.