The primary objective of this study is to investigate the effectiveness of using Hospital Fit as part of the physiotherapy treatment on average time spent walking per day in patients hospitalised at the Medical Oncology or Cardiology Departments of the Maastricht University Medical Center (MUMC+) and Radboud University Medical Center (Radboudumc) compared to patients who received physiotherapy before implementation of Hospital Fit. Secondary: to investigate the effectiveness of using Hospital Fit as part of the physiotherapy treatment on average time spent standing per day, average time spent lying/sitting per day, average number of transitions per day and the Modified Iowa Level of Assistance scale (mILAS) scores in hospitalised patients. Besides, the reach, efficacy, adoption, and implementation of using Hospital Fit as part of the physiotherapy treatment will be investigated from the perspective of both patients and healthcare professionals.

Rationale: Physical inactivity is a major, underrecognised problem in patients during their hospital stay. Patients spend between 87 and 100% of their time lying or sitting. This physical inactivity has been associated with adverse outcomes such as functional decline, increased length of hospital stay and mortality. Digital health tools could be valuable to prevent negative effects of inactivity. Hospital Fit is a promising app-based intervention to stimulate physical activity by 1) continuous physical activity monitoring, 2) personalised goalsetting, 3) providing patients insight in their functional recovery, 4) providing patients tailored exercise programs, 5) informing patients about benefits of physical activity, and 6) reminding patients to use Hospital Fit 7) linking the data to the electronic medical record, making it available for other healthcare professionals.

Objectives: Primary: to investigate the effectiveness of using Hospital Fit as part of the physiotherapy treatment on average time spent walking per day in patients hospitalised at the Medical Oncology or Cardiology Departments of the Maastricht University Medical Center (MUMC+) and Radboud University Medical Center (Radboudumc) compared to patients who received physiotherapy before implementation of Hospital Fit. Secondary: 1) to investigate the effectiveness of using Hospital Fit as part of the physiotherapy treatment on average time spent standing per day, average time spent lying/sitting per day, average number of transitions per day and the Modified Iowa Level of Assistance scale (mILAS) scores in hospitalised patients; and 2) to investigate the reach, efficacy, adoption, and implementation of using Hospital Fit as part of the physiotherapy treatment from the perspective of both patients and healthcare professionals.

Study design: A prospective, multi-centre, stepped-wedge cluster randomised trial will be performed to investigate the effectiveness of Hospital Fit. Additionally a process evaluation will be performed using questionnaires and semi-structured interviews in patients and focus-group interviews in healthcare professionals.

Study population: In total 180 patients hospitalised at the Medical Oncology Department or Cardiology Departments at the MUMC+ or Radboudumc will be included to study the effectiveness. The process evaluation will be performed in the intervention group using a questionnaire in all 90 patients, semi-structured interviews in 24 purposefully selected patients (or less if data saturation is reached), and focus group interviews in 24 healthcare professionals (i.e., physiotherapists, nurses, and physicians (assistants).

Intervention: Physical activity will be measured in all patients with an accelerometer until discharge with a maximum of nine days. The control group will receive usual care physiotherapy (n=90), while the intervention group will use Hospital Fit additionally (n=90).

Main study parameters/endpoints: Primary outcome parameter: average time spent walking per day (min). Secondary outcome parameters: average time spent standing and lying/sitting per day (min.), average number of transitions from lying/sitting to standing/walking per day, and mILAS score per day. Outcome parameters process evaluation: participation; representation; perceived efficacy; use of app; use of different functionalities; barriers and facilitators to Hospital Fit use; and expected maintenance.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The burden and risks on patients are minimal. The control group will receive usual care physiotherapy and will wear an accelerometer. The intervention group will use Hospital Fit additionally. Wearing a small accelerometer and using Hospital Fit should not be a burden to patients. The only burden is the time it takes to prepare subjects (install app, explain study). No invasive interventions will take place. Anticipated benefits of Hospital Fit use include improved physical activity, therewith reducing the negative effects associated with low physical activity.

Inclusion Criteria patients:

• Over 18 years old.
• Receiving physiotherapy at the Medical Oncology Department or the Cardiology Department at the MUMC+ or Radboudumc.
• Enough understanding of the Dutch language.
• Owning a smartphone (operating system: at least iOS 13.0 or Android 8.0).
• Able to use a smartphone app.
• Able to walk independently 2 weeks before admission, as scored on the Functional Ambulation Categories (FAC >3).

Exclusion Criteria patients:

• A contraindication to walking (as reported by a medical specialist in the electronic medical record).
• A contraindication to wearing an activity monitor, fixed by a hypoallergenic plaster at the upper leg (such as active bilateral upper leg infection, severe oedema or bilateral transfemoral amputation).
• Admitted for cancers of the head and neck (i.e., cancer in the oral cavity, throat (pharynx), voice box (larynx), paranasal sinuses and nasal cavity, salivary glands).
• Admitted with cardiac arrhythmia and hemodynamic instability requiring medication over 48 hours (i.e., beta blockers or noradrenaline) or invasive treatment (i.e., pacemaker or defibrillator implementation).
• Mentally incapacitated subjects as reported by healthcare professionals in the medical record. When any doubt arises, the patient will be excluded.
• Impaired cognition (delirium / dementia) as reported in the medical record by a healthcare professional. When any doubt arises, the patient will be excluded.
• Unable to participate in the informed consent procedure or unable to provide written informed consent.
• A life expectancy shorter than 3 months as mentioned by the medical specialist in the medical record.
• Previous participation in this study.

Inclusion Criteria healthcare professionals:

• Employed as physiotherapist, nurse or physician (assistant) at the Medical Oncology Department or the Cardiology Department.
• Working at the MUMC+ or Radboudumc for at least one month.

Exclusion Criteria healthcare professionals:

• No participation in care for patients at the Medical oncology Department or Cardiology Department during the intervention phase (e.g., absence or research employment).

We do not intent to make IPD available to other researchers.