In this research project, we want to investigate whether the combined intake of proteins and tea extract has an influence on muscle regeneration compared to the sole intake of proteins or a placebo product. In the study, you will be randomly assigned to one of 3 groups. Neither the research group nor you will know which group you are assigned to. The study lasts 5 days for you as a participant. During these 5 days you will have to attend a total of 5 appointments in our laboratory. The groups differ only in the intake of the regeneration product, otherwise all measurements and appointments are identical. You will jog downhill for 30 minutes on the first day in order to strain your muscles. In order to be able to draw conclusions about the regeneration of your muscles, we will carry out the following measurements on all 5 days: Blood sampling at the fingertip, ultrasound of the thigh muscle, pain tolerance of the thigh muscle, strength tests of the thigh muscle, muscle function of the thigh muscle and jumping performance.