Trial registration
ReBEC RBR-7rvhpq9 . Registry name: The effect of rehabilitation in hospitalized COVID-19 patients. Registered on 17 March 2021.Retrospectively registered. FULL PROTOCOL: "The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol".