In the present project, the framework conditions of outpatient rehabilitation at the Bonn Center for Outpatient Rehabilitation will now be used to prove whether sports science-controlled strength and BFR training has a similar effect in the postoperative rehabilitation phase. Strength and BFR training in medical training therapy complements daily exercise therapy in order to ensure implementation in the guideline-based rehabilitation process. . The interventions are carried out as part of the exercise therapy units in outpatient rehabilitation ETM01 following the RTS hip and knee TEP basis KTL 2020.