The goal of this clinical trial is to learn how wearing the Hypershell lower-limb exoskeleton affects perceived fatigue during everyday mobility activities in adults aged 65 years and older. The main questions it aims to answer are: * Does active assistance from the Hypershell reduce the development of perceived fatigue during repeated everyday mobility tasks? * Does wearing the Hypershell affect how long participants can perform the protocol and how many tasks they can complete before reaching a high level of fatigue? * How do participants perceive the usability, comfort, and overall experience of using the Hypershell? * What are the biomechanical and physiological responses from wearing the Hypershell? Researchers will compare two conditions: performing the mobility protocol without the Hypershell and wearing the Hypershell with active assistance. Participants will: * Attend one baseline session including questionnaires, physical tests, and familiarization with the Hypershell and study procedures. * Attend two experimental sessions in a randomized order, with at least one week between sessions. * Complete a laboratory-based mobility protocol including daily activities such as standing up from a chair, walking, stair climbing, slope walking, walking on uneven surfaces, carrying an object, and performing a cognitive task while walking. * Report their perceived fatigue throughout the protocol using the Borg CR10 scale. * Wear non-invasive sensors that measure physiological responses and movement during the experimental sessions. * Provide feedback about their experience using the HyperShell.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
NONE
Enrollment
20
Participants will perform the FATIG'AGE multi-task functional mobility protocol. The protocol includes a fixed sequence of daily activities such as walking, sit-to-stand transitions, stair ascent and descent, slope walking, walking on uneven surfaces, carrying an object, and dual-task walking.
Participants wear the Hypershell hip exoskeleton with active assistance. In the active-assistance condition, the device uses motion sensors to detect the user's movements and provides powered assistance to support hip movement during functional mobility tasks
Brubotics Rehabilitation Research Center
Brussels, Belgium
Rate of Perceived Fatigue Progression
Rating of Perceived Fatigue (RPF) will be assessed verbally using the Borg Category-Ratio 10 (CR10) scale after each task of the FATIG'AGE protocol. The Borg CR10 ranges from 0 (no exertion) to 10 (maximal exertion). The rate of increase in RPE across consecutive task executions will be determined for each experimental condition, with a lower rate indicating a slower development of perceived exertion.
Time frame: During each experimental session, up to 60 minutes
Protocol Duration Until Termination
Total time, in minutes, that the participant performs the FATIG'AGE protocol before reaching a predefined termination criterion: Borg CR10 greater or equal to two consecutive score of 8, or the maximum protocol duration of 60 minutes. Longer duration indicates that the participant was able to perform the protocol for longer before termination.
Time frame: During each experimental session, up to 60 minutes
Number of Executed Tasks Until Protocol Termination
Total number of individual FATIG'AGE task executions completed before reaching a predefined termination criterion: Borg CR10 equal or greater to two consecutive scores of 8, or the maximum protocol duration of 60 minutes. A higher number indicates that more functional mobility tasks were completed before protocol termination.
Time frame: During each experimental session, up to 60 minutes
Global Perceived Effect of the Hypershell
Participants will rate the perceived effect of wearing the HyperShell on their physical performance using the Global Perceived Effect (GPE) scale. The GPE is a 7-point Likert scale ranging from perceived deterioration to perceived improvement. The questionnaire will be administered following the HyperShell transparent and active-assistance conditions.
Time frame: Immediately after each applicable experimental session
Usability of the HyperShell Assessed With the System Usability Scale
Usability of the Hypershell will be assessed using the 10-item System Usability Scale (SUS). Items are rated on a 5-point Likert scale and transformed into a total score ranging from 0 to 100, with higher scores indicating greater perceived usability.
Time frame: Immediately after the Hypershell active-assistance experimental session
User Experience With the Hypershell Assessed With the User Experience Questionnaire
User experience with the Hypershell will be assessed using the 26-item User Experience Questionnaire (UEQ). The questionnaire assesses six dimensions: attractiveness, perspicuity, efficiency, dependability, stimulation, and novelty. Items are scored on a semantic differential scale ranging from -3 to +3, with higher scores indicating a more positive user experience.
Time frame: Immediately after the Hypershell active-assistance experimental session
Lower-Limb Muscle Activity
Surface electromyography will be continuously recorded from selected lower-limb muscles (knee extensor, foot dorsi- and plantar flexor) during the FATIG'AGE protocol. Muscle activation amplitude and frequency will be derived from the EMG signal and compared between experimental conditions. Unit of Measure: percent of reference contraction (%)
Time frame: Continuously during each experimental session, up to 60 minutes
Heart Rate
Heart rate will be continuously recorded during the FATIG'AGE protocol using electrocardiography. Heart rate will be examined across the protocol and between experimental conditions. Unit of Measure: beats per minute (bpm)
Time frame: Continuously during each experimental session, up to 60 minutes.
Respiratory Rate
Respiratory rate will be continuously recorded using an inductive plethysmography band during the FATIG'AGE protocol and examined across the protocol and between experimental conditions. Unit of Measure: breaths per minute
Time frame: Continuously during each experimental session, up to 60 minutes.
Galvanic Skin Response
Galvanic skin response will be continuously recorded using finger electrodes during the FATIG'AGE protocol and examined across the protocol and between experimental conditions. Unit of Measure: microsiemens (µS).
Time frame: Continuously during each experimental session, up to 60 minutes.
Lower-Limb Muscle Oxygen Saturation
Muscle oxygen saturation will be continuously recorded from selected lower-limb muscles (knee extensor, foot dorsi- and plantar flexor) using near-infrared spectroscopy sensors during the FATIG'AGE protocol and examined across the protocol and between experimental conditions. Unit of Measure: percent (%)
Time frame: Continuously during each experimental session, up to 60 minutes.
Changes in Motion Data
Inertial Measurement Unit (IMU) data will be collected continuously throughout the FATIG'AGE protocol. The IMUs will record motion-related signals, including segment orientation, linear acceleration, and angular velocity. Data acquisition will explore changes in kinematics and gait parameters.
Time frame: Continuously during each experimental session, up to 60 minutes.
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