The purpose of this observational study is to quantify physical activity patterns in patients with severe acquired brain injury admitted for in-hospital rehabilitation.

Patients admitted for rehabilitation will be included for two periods of one-week monitorization of physical activity. The investigators will include all patients with moderate to severe brain injury.

This is an observational cross-sectional study including patients 18 years or above. Patients with conditions such as unstable fractures that restricts mobilisation are excluded. Physical activity is measured continuously during rehabilitation at two separate seven-day periods using a body-worn activity tracker. The first period will be initiated in the early phase of rehabilitation (3 days after admission) and the second at the late phase (10 days before discharge).

Baseline variables considered predictors, confounders or modifiers for physical activity will be collected along with registration of variables during the measurement periods and functional outcome variables at discharge.

Inclusion Criteria:

• 18 years old

Exclusion Criteria:

• Planned discharge within two weeks
• Fractures of lower extremities, pelvis or spine prohibiting weight-bearing
• Amputation of lower extremities

Patients with acquired brain injury of any cause admitted for rehabilitation at the department will be recruited.

Data that are truly anonymised will be uploaded to Zenodo after the publication of the study. Data that we are not able to truly anonymise will be available upon reasonable request.

Two years after study completion. Data will be available for at least ten years.

Any researcher can make contact to primary investigator or sponsor with pre-planned project description.