The aim of the "FormFit" research project, approved by the AiF (Working Group of Industrial Research Associations) under the ZIM (Zentrales Innovationsprogramm Mittelstand), is to reduce fatigue and the frequency of injuries in football. This reduction is achieved through the development of a 3D-printed, individually customized, topology-optimized insole with an integrated heel contour. In addition to being tailored to the individual anthropometric and biomechanical characteristics of the football player, the insole is also adapted to the shoe and its specific stud configuration.