The landmark randomised trial by Schweickert and colleagues evaluated early physical and occupational therapy in mechanically ventilated critically ill adults. Patients received therapy while still in the ICU, coordinated around sedation and ventilator management rather than waiting until after critical illness had resolved. The study demonstrated that very early rehabilitation could improve functional outcomes and reduce the burden of ICU-acquired weakness. The trial was influential because it challenged the assumption that mechanically ventilated patients should remain largely immobile until they are clinically stable enough for conventional rehabilitation. The clinical principle remains highly relevant: immobility is not a neutral state. Muscle weakness, deconditioning and cognitive complications can persist after discharge, contributing to prolonged recovery and impaired quality of life. Early mobilisation therefore forms part of acute critical-care treatment, not simply a rehabilitation service delivered later. This directly supports CritiCARE 2026 sessions on early mobilisation, ICU physiotherapy, ABCDEF care and post-ICU syndrome. The practical message is to assess mobilisation readiness daily, coordinate physiotherapists and bedside staff with respiratory and medical teams, and progress from passive movement to sitting, standing and walking as clinically appropriate. Safety screening and careful monitoring remain essential, but prolonged mechanical ventilation alone should not automatically mean prolonged bed rest.