The thesis presents a final project for the Mechanical engineering degree consisting of 15 ECTS. The topic of this thesis is an eco-friendly trainer, it consists of the following aspects, which have to be reviewed and solved to some extent: introduction, literature survey, energy generation technologies, material selection, strength calculations, manufacturing methods and conclusion. The idea is to reform an existing gym machine to become more eco-friendly. The machine will be chosen by a target group of people through a survey. Other selection criteria are functionality and energy efficiency. The chosen machine will be analyzed, and a modern energy generator will be introduced into a trainer. Further, the material selection will be done, fulfilling all necessary requirements, such as safety, functionality, recyclability, etc. As much as possible engineering tools are planned to be used during the execution, such as formulas, 3D and stress analysis tools, comparison programs, etc. The readiness to obtain a new knowledge of engineering solution and innovative thinking approach is going to be used if required. After an execution and project’s hand-in, a brief, but clear view of the product shall be presented on the presentation.