Procedures ICU patients were recruited as soon as they were suitable for early ICU rehabilitation (see inclusion criteria). After baseline measurements patients were randomly assigned to the early rehabilitation group. A computer-generated, permuted block randomization scheme was used considering sex, age, LOS at the ICU and diagnostic category to allocate patients to the early rehabilitation group or usual care group. Each assignment was operated through a web-based randomization system (https://www.meduniwien.ac.at/randomizer) by an investigator with no further involvement. All included patients received the same usual care physical therapy, as ordered by the primary care team, during their stay at the ICUs. Unresponsive patients underwent passive range of motion exercise for all limbs. Once patient interaction was achieved, no matter if the patient was mechanically ventilated, a progressive early rehabilitation program was initiated starting with active assisted or active range of motion exercises and breathing techniques. If these exercises were tolerated, treatment was advanced to bed mobility exercises, transferring to upright sitting and sitting balance activities. The early rehabilitation program progressed to participation in activities of daily living, sit-to-stand transferring, pre-gait exercise and finally up to walking. Progression of activities was dependent on patient tolerance and stability (systolic blood pressure between 65 and 200 mm HG, heart rate between 40 and 130 beats per minute, respiratory rate between 5 and 40 breaths per minute, and pulse oximetry above 88%). Patients were discharged to a general ward as soon as their medical condition was sufficiently stable, regardless of their functional status.