The main aim of this study is to investigate whether increasing the amount of physical activity in frail older people during hospital based rehabilitation is associated with better mobility outcomes compared to usual care. A second aim is to investigate whether this physical activity intervention is associated with improvements in health related quality of life. Finally we plan to investigate whether increasing the amount of physical activity during rehabilitation is cost effective, measured from a health system perspective, compared with usual care.

Older people receiving inpatient rehabilitation will be randomly assigned to an intervention group, who will receive extra physical activity on weekdays and weekends or a control group, who will receive additional activities based on social interaction. The activity sessions will be individualized to the particular participant. Both groups of people will be assessed at baseline, discharge from hospital and at 6 months following discharge. The intervention group will be provided with one or two extra sessions on weekdays and two extra sessions on weekends for the duration of their rehabilitation stay. To account for the extra physiotherapy time that the intervention group receives, the people in the control group will spend the same amount of time performing other activities, such as cards, board games or reading, whilst seated. To ensure the safety of the participants in this study, each physical activity session will be supervised by either a physiotherapist or allied health assistant.

Hypothesis 1: The primary hypothesis is that, compared with usual care, increasing the amount of physical activity in frail older people during rehabilitation will lead to more optimal mobility at discharge, as measured by gait speed.

Secondary hypotheses are that, compared with usual care, increasing the amount of physical activity during rehabilitation will:

Hypothesis 2: lead to significantly greater improvements in mobility and function both at discharge and six months following discharge.

Hypothesis 3: lead to better quality of life six months following hospital discharge, measured using the EuroQol Health (EQ5D) Questionnaire and the EuroQol-Visual Analogue Scale (EQ-VAS).

Hypothesis 4: be cost effective compared to usual care

Inclusion Criteria:

• over 60 years of age
• a goal of admission is to 'improve weight-bearing mobility or improve walking' as determined by either the admission referral or the treating therapist

Exclusion Criteria:

• specific medical restrictions that limit mobilisation (e.g. non weight bearing)
• if already enrolled in a different Randomised Controlled Trial
• previously enrolled in the current trial
• the primary reason for admission is awaiting a residential care placement
• the primary reason for admission is for carer training