VR-C-REHAB is a single-group pilot and feasibility study examining the practicality of implementing virtual-reality-assisted ergometer cycling as an adjunct to usual municipal inpatient rehabilitation for older adults (≥65 years). Many individuals admitted to temporary inpatient care present with low physical activity levels and fluctuating motivation, reducing the achievable exercise dose. Virtual reality may enhance engagement, enjoyment, and adherence, but its feasibility in this setting must be evaluated before conducting a future effect trial.

The primary objective is to determine whether participants can achieve an adequate exercise dose, defined as the proportion of completed VR-cycling sessions out of those offered (target: ≥75%). Secondary feasibility outcomes include recruitment rate, safety and acceptability, and total cycling time. Exploratory outcomes include change in the 10-Meter Walk Test and session-level motivation (0-10). The intervention consists of 15 minutes of VR-assisted cycling, three times weekly for up to four weeks, delivered alongside standard rehabilitation.

Data are collected at baseline, during each session, and at completion. Analyses are descriptive, focusing on the precision of feasibility estimates. Progression criteria (Go/Amend/Stop) are based on adherence, recruitment, and safety. The results will inform the design and implementation of a subsequent controlled study.

Background and Rationale:

Elderly individuals with diminished physical capacity who are admitted to temporary inpatient rehabilitation often exhibit low levels of physical activity and motivation, which can adversely affect the exercise dose during their stay. Cycling is recognized as a safe and effective form of exercise; however, its implementation is often hindered by low commitment and fluctuating daily energy levels.

Virtual reality (VR) has the potential to enhance motivation, perceived enjoyment, and adherence to training by providing distraction, engagement, and a more stimulating exercise environment. Prior to conducting a potential impact study, it is essential to assess the feasibility of recruitment, implementation, acceptance, and exercise dose within municipal inpatient rehabilitation settings.

Objective and Research Question:

Overall Objective:

To investigate the feasibility of a VR-assisted ergometer cycling intervention in conjunction with standard treatment for older adults (aged 65 and above) in rehabilitation during municipality-based inpatient rehabilitation care.

Primary Feasibility Question:

Can participants achieve an adequate exercise dose, as measured by the proportion of completed VR-assisted ergometer cycling sessions out of the total offered sessions, with a feasibility target of ≥75%?

Secondary Feasibility and Exploratory Questions:

What is the recruitment rate (percent proportion of approached individuals who consent to participate)? How does the 10-Meter Walk Test (10 MWT) progress from baseline to completion, reported in m/s? Motivation, Scale 0-10, 10 indicate the highest degree of motivation What is the total duration of cycling (in minutes) completed during the intervention period?

Setting:

Location: Municipality-based inpatient rehabilitation care in the municipality of Hørsholm, managed by the municipal rehabilitation unit.

Regular Treatment: Standard rehabilitation, typically comprising individual and/or group-based training, activities of daily living (ADL) interventions, and mobilization following clinical assessment.

Intervention:

Overview:

Intervention: 15 minutes of cycling with VR goggles in addition to regular treatment.

Frequency: Three times weekly. Duration: Up to 4 weeks (dependent on discharge timing). Delivery: Supervised by physiotherapists or therapeutic staff according to local practices.

Implementation:

Bicycle: Stationary bicycle/ergometer cycle [insert model]. VR Equipment: SyncSense.

Session Structure:

Brief health check (e.g., assessment of tiredness, dizziness, nausea, pain, blood pressure/pulse if relevant) Setup of VR and safe positioning 15 minutes of cycling (pauses permitted) brief conclusion and documentation of any discomfort/side effects.

Dosage and Progression:

The approach is "pragmatic" feasibility, with intensity adjusted to daily energy levels.

The therapist may modify the load (resistance) and pauses to facilitate completion.

Simultaneous Treatment:

Regular rehabilitation continues unchanged and is documented in general terms (e.g., number of therapy contacts per week, if feasible).

Sample Size (Pilot/Feasibility Rationale) A power calculation for the effect will not be conducted. The sample size is determined to estimate feasibility parameters with reasonable precision.

Planned inclusion is N = [12-20] participants. The rationale is to estimate adherence and recruitment rates with confidence intervals and to identify practical implementation barriers.

Recruitment and Consent Screening: Conducted daily/weekly through admission lists/referrals to inpatient care.

Recruitment Procedure:

Involves the identification of potentially suitable individuals Provision of verbal and written information Reflection time in accordance with local guidelines Collection of informed consent A log will cover the number screened, eligible, approached, consented, and causes for dropout/"no".

Statistics and Analysis Plan

General Principle:

The primary descriptive analysis will focus on feasibility estimates and precision, specifically confidence intervals.

No formal hypothesis testing for effect will be conducted; secondary outcomes will be reported in an exploratory manner.

Primary Outcome

Adherence will be reported as follows:

Percent of offered sessions completed. Up to 4 weeks (from baseline to discharge or week 4, whichever occurs first Average (SD) and median (IQR) per participant Collective share of completed/offered sessions for the cohort Recruitment Rate Proportion in percent; Percent consented among approached Causes for non-participation will be categorized. 10MWT and Bicycle Time Change from baseline to finish will be reported as mean change (SD) or median change (IQR).

Visualization: individual spaghetti plots for 10MWT. Lack of Data Feasibility will be assessed by registering the cause of missing measurements (e.g., discharge, illness, logistics).

No imputation will be performed as a general rule; transparency in reporting will be maintained.

Bias and Assurance of Quality Standardized instruction for 10MWT will be provided. Staff will be trained in setting up VR and ensuring safety. Predefined criteria for "offered session" versus "not offered" will be documented, including staff- and illness-related causes.

Injury and Adverse Events All VR-related discomforts (e.g., nausea, dizziness) will be registered. Severe incidents will be reported following local procedures. Stop criteria per session include significant dizziness, nausea, chest pain, acute deterioration, or therapeutic assessment.

Data Management and Security All physical documents, including training records, test results, and the identification key (linking participant IDs to personal information), will be stored in a double-locked cabinet at the primary project site. Access is restricted to authorized project personnel.

Electronic data for statistical analysis will be entered into a secure, encrypted network folder within the municipality's protected IT infrastructure. These datasets will be maintained in an anonymized format, where participants are identified solely by a project-specific ID. No personally identifiable information will appear in the electronic dataset.

The identification key will remain exclusively in paper format and will be stored in the same double-locked cabinet as the physical training and testing data. This key will not be digitized and will only be accessed by the principal investigator or designated personnel for validation or follow-up purposes.

All data handling complies with GDPR regulations and principles for secure management of sensitive personal information. Data will be retained for five years after project completion, after which it will be securely destroyed or archived according to ethical and legal requirements.

The project has been declared to the local ethics committee of the capital region, Denmark, and has received identification number: F-26001623

Communication Results will be reported in accordance with CONSORT pilot/feasibility guidelines, including a flowchart and clear separation between feasibility results and exploratory effect indicators.

Plan: conference abstract and manuscript in a relevant rehabilitation/geriatric journal.

Inclusion Criteria:

• Age ≥65 years
• Referred to rehabilitation during a stay at temporary inpatient care
• Assessed by a therapist as capable of participating in seated cycling (possibly supervised)
• Able to provide informed consent (with relevant support according to local guidelines, if necessary).

Exclusion Criteria:

• Medical contraindications to moderate physical activity/cycling (e.g., unstable angina, uncontrolled arrhythmia, acute infection with significant impact)
• Severe dizziness/vestibular symptoms likely to be exacerbated by VR use
• Known photosensitive epilepsy or other conditions posing significant risk with VR stimulation
• Unresolved vision/perception issues or severe nausea rendering VR use unsuitable
• Participation in another intervention study that interferes with this intervention.

Anonymized data on all outcomes will be provided upon request during or after a publication proces.

Data will be alailable from june 2026 onwards

By contacting PI data will be provided on request.