This study investigates a new training method designed to help older adults preserve their muscle strength during hospitalization. When older adults are admitted to the hospital and spend long periods in bed, their muscles can weaken very quickly. This condition is known as hospital-associated disability (HAD), and it can lead to longer hospital stays, reduced independence, and an increased risk of complications or even death. Conventional strength training with heavy weights is often too demanding or unsafe for frail patients, especially just after surgery or illness. As a safer alternative, this study combines light muscle exercises with a medically validated technique called blood flow restriction (BFR), which gently reduces blood flow to the leg to boost the effects of light exercises.
To make training more engaging and personalized, the GHOSTLY+ system was developed. This system consists of a game played on a tablet that responds to muscle activity through sensors placed on the skin. While playing, patients perform isometric muscle contractions (exercises where the muscles tighten without moving the joint) that help to maintain and rebuild strength. The system was carefully designed in collaboration with patients and therapists, and it has already been tested in a smaller pilot study at UZ Brussel.
The current study is a multicenter randomized controlled trial, taking place at UZ Brussel, UZ Antwerpen, and UZ Leuven. A total of 120 patients aged 65 or older will be recruited, all of whom are hospitalized and are unable to bear weight or transfer (e.g., from lying to seated position). Participants will be randomly assigned to one of two groups. One group receives standard physiotherapy. The other group receives standard therapy plus the GHOSTLY+ training program.
Those in the GHOSTLY+ group will train at least five times per week for two weeks, or until discharge from the hospital. Each training session lasts approximately 30 minutes and involves three sets of 12 muscle contractions, guided by the game. The difficulty is adapted to the individual's muscle strength, which is measured at the beginning of the training using a built-in calibration protocol. During the session, a smart cuff is applied to the upper leg to partially restrict blood flow - a technique shown to safely enhance muscle adaptation. The cuff is inflated to 50% of the individual's arterial occlusion pressure and deflated after the session ends. Before beginning, participants receive a short training session with a physiotherapist. Our pilot study (Debeuf et al., 2025) shows that most patients can use the system independently after about one hour of instruction.
Measurements and evaluations take place at three timepoints: before starting the training, after one week, and again at discharge. The main goal is to assess leg muscle strength, which will be measured using a handheld device called a dynamometer. In addition, researchers will collect information on:
* Muscle mass, via ultrasound of the thigh muscle * Functional capacity, using a 30-second sit-to-stand test and a walking scale (Functional Ambulation Category) * An index of independence in activities of daily living (Katz scale) * Cognitive functioning, using the Mini-Mental State Examination (MMSE) * Time spent bedridden and total length of hospital stay * Therapy adherence and user experience, via usage data and questionnaires * Muscle activity signals, such as fatigue, recorded during gameplay * Implementation outcomes (collected via surveys, interview, site logbooks)
The study will also assess how easily the GHOSTLY+ system can be implemented in real hospital environments. This includes evaluations of user satisfaction, therapist feedback, and how consistently the system is used across hospital settings. Information will be gathered through structured interviews, surveys, and data logs from the app. These insights are crucial to understanding whether GHOSTLY+ can be broadly adopted in other hospitals in the future.
Blood flow restriction training is considered very safe when applied correctly and is already used in rehabilitation clinics and sports medicine worldwide. Over 300,000 sessions have been conducted internationally, with a very low rate of complications. Minor discomfort, such as temporary tightness or muscle fatigue, may occur, but the risk of serious side effects is extremely small.
By participating in this study, patients may benefit from improved muscle strength, reduced time spent in bed, and greater physical independence at discharge. The study also contributes to the development of more effective and enjoyable rehabilitation methods for older adults in hospitals.
Hospitalized, and expected to remain hospitalized for approximately 14 days
65+ yrs
Unable to bear weight or transfer independently and at high risk of muscle strength loss due to prolonged immobility
Contraindications for physical exercise as assessed by the treating physician using the risk assessment tool proposed by Kacin et al. (2015) (can be overruled by the physician)
Contraindications for blood flow restriction as assessed by the treating physician (can be overruled by the physician)
Cognitive impairment (MMSE score < 19)
Any condition that renders the patient unable to understand instructions or safely interact with the GHOSTLY+ system
Parallel
Gamified isometric strength training with blood flow restriction
DeviceGHOSTLY+ is an interactive, EMG-driven serious game combined with blood flow restriction (BFR) therapy. Participants will undergo isometric quadriceps contractions guided by gameplay, with each session consisting of 3 sets of 12 contractions at 75% of their maximum voluntary contraction (MVC), as determined by in-app calibration. BFR will be applied using a smart cuff inflated to 50% of the participant's arterial occlusion pressure (AOP). Sessions will be performed independently by the patient during non-therapy time, with a minimum of 5 sessions per week over a 2-week period (or until discharge).
Standard Physiotherapy
Other interventionUsual standard-of-care physiotherapy as per hospital guidelines. This typically consists of supervised therapeutic sessions prescribed by the clinical team, including mobility exercises, transfer practice, and functional strengthening, depending on the patient's clinical needs and recovery stage. Participants do not perform structured lower-limb strength training outside of formal therapy sessions.
Maximal isometric muscle strength
Maximal isometric muscle strength of the lower limbs will be assessed using a handheld dynamometer (MicroFET or equivalent). The test involves measuring the peak isometric force generated by the quadriceps muscle group during a voluntary contraction against resistance, while the participant is in a standardized seated position. Each participant will perform three maximal voluntary contractions (MVCs) with sufficient rest between trials. The highest recorded peak force (Newtons) will be used as the representative value. Testing will be conducted at three time points: baseline (T0), after one week (T1), and at two weeks or at the time of hospital discharge, whichever occurs first (T2). Outcome assessors are blinded to group allocation. The change in maximal isometric quadriceps strength (Newtons) from baseline to discharge will serve as the primary endpoint to evaluate the intervention's effectiveness in preserving muscle strength during hospitalization.
Electromyography (EMG) Signal Analysis
Analyses will be performed on EMG data to extract the neuromuscular parameter: signal amplitude.
Cross-sectional area of the Rectus Femoris Muscle
The muscle mass of the m. rectus femoris will be assessed using a bedside ultrasound system. The cross-sectional area (CSA) of the muscle will be measured in a supine position at a standardized mid-thigh location. Assessments will occur at baseline (T0), week 1 (T1), and discharge (T2). This outcome is intended to capture muscle architecture changes associated with strength loss or preservation.
Functional performance - 30 second sit-to-stand test
If medically permitted (i.e., participant is weight-bearing), functional lower-limb endurance will be measured using the 30-second sit-to-stand test (30s-STS). Participants will be asked to rise from a standardized chair to a full standing position and sit back down as many times as possible in 30 seconds. Standardized instructions and encouragement will be used. This test is a validated measure of functional strength and endurance. Performance will be assessed at T0, T1, and T2.
Functional ambulation category (FAC)
The Functional Ambulation Category (FAC) is a 6-point scale used to assess the level of independence in walking. It ranges from 0 (non-functional ambulation) to 5 (independent ambulation in all environments). Assessment is performed at T0, T1 and T2. FAC will help determine the extent to which patients regain or retain ambulatory capacity during hospitalization.
Implementation Outcome: Acceptability
Acceptability refers to how suitable, satisfying, or agreeable the GHOSTLY+ intervention is perceived to be by its users - including both patients and healthcare providers. This will be assessed through structured surveys and semi-structured interviews or focus groups conducted after the intervention period. Topics will include perceptions of usefulness, ease of use, clarity of instructions, and perceived value. Data will be analyzed qualitatively using thematic analysis and quantitatively via survey responses to gauge overall user satisfaction and alignment with clinical needs.
Implementation Outcome: Adoption
Adoption reflects the initial decision and action to try or employ the GHOSTLY+ system by healthcare professionals at each participating hospital site. This will be measured using administrative logs, recruitment records, and surveys documenting how many physiotherapists or staff chose to engage with the intervention, and what factors influenced their willingness to do so. Qualitative interviews will further explore facilitators and barriers influencing the uptake of the system in routine clinical workflows.
Implementation Outcome: Fidelity
Fidelity refers to the degree to which the GHOSTLY+ intervention was delivered as intended. This includes adherence to the planned session structure (e.g., 3 sets of 12 repetitions at 75% MVC with BFR), use of app features such as calibration and real-time feedback, and proper application of the BFR cuffs. Fidelity will be monitored via usage logs, therapist checklists, and adherence data from app dashboards. Deviations from the protocol will be documented and analyzed to understand variability in delivery and potential impact on outcomes.
Implementation Outcome: Feasibility
Feasibility captures the extent to which GHOSTLY+ can be successfully used in a real-world clinical setting, given practical constraints such as staffing, time, space, and technology integration. It will be assessed through clinician and staff surveys, logbooks, and feedback interviews. Indicators include training burden, technical difficulties, workflow fit, and perceived logistical challenges.
Click on the lead sponsor to view all of their trials.
Vrije Universiteit Brussel
Lead sponsor
Universitair Ziekenhuis Brussel
Collaborator
University Hospital, Antwerp
Collaborator
Universitaire Ziekenhuizen KU Leuven
Collaborator
Universiteit Antwerpen
Collaborator
KU Leuven
Collaborator
