Physical recovery following a critical illness is important for patients, family and clinicians.1–3 However, there is limited beneficial effect demonstrated from the intervention studies that have investigated physical rehabilitation across the continuum of critical illness recovery, starting in the intensive care unit (ICU) and continuing to the community setting with home-based rehabilitation and follow-up clinics4–8 What is the reason for this lack of treatment effect? As with all trials that show a lack of effect, we must consider a number of factors, including the intervention delivered, the target population and the outcome measure used.

In the recent RECOVER trial,8 there was an improvement in the functional status of patients following critical illness, as evidenced by the Rivermead Mobility Index (RMI); however, the delivery of a post-ICU bundled therapies intervention did not...