Background: Long-COVID, which might develop after a SARS-CoV-2 infection, is a rather new disease without standardized treatment strategies. A large number of approaches that integrate physical activity have been described in the literature, and this systematic review aims to examine changes in symptom severity, physical fitness, respiratory symptoms and quality of life during training and identify factors that might influence the respective outcomes. Methods: A literature search was conducted using the databases Pubmed, PEDro, BioMed Central, EBSCOhost, ProQuest and the ZBSport from 13 February 2024 to 27 February 2024, and 39 studies fulfilled the search criteria. Results: The analyzed study designs varied regarding the type of intervention (isolated vs. multidisciplinary), duration and intensity of training sessions and overall length of the program. Individualized holistic concepts of physical activity paralleled by additional approaches demonstrated high effectiveness. However, many of the participants continue to suffer from Long-COVID after the intervention. Conclusions: Long-COVID treatment should be individualized, multifactorial and not limited in time and should consider each patient’s pre-existing conditions and individual course of the disease to provide the best possible support and care.