Investigation of Motorized Lower-limb Prostheses

The goal of this clinical trial is to learn if a motorized prosthesis can improve mobility in individuals with amputation. The main question it aims to answer is:

• Does motorized prosthesis improve ambulation speed, balance, control, or efficiency when performing everyday activities?
• What problems arise when using a motorized prosthesis? Researchers will compare mobility of the participants when using and not using the motorized prosthesis to see if mobility and/or function improves.

Participants will perform various activities with and without the motorized prosthesis including:

• Walking at a mild incline/decline (0°-15°) on treadmill or over-ground
• Ascending or descending stairs
• Stand to sit and sit to stand transitions
• All terrain walking over ground
• Turning
• Any combination of the above-mentioned activities

Study Overview

• Status: Not yet recruiting
• Conditions: Ambulation With the "Take Home" or Passive Prosthesis; Ambulation With the Motorized Prosthesis in the "Off" Configuration; Ambulation With the Motorized Prosthesis in the "Transparent" Condition; Ambulation With the Motorized Prosthesis in the "Powered" Condition
• Intervention / Treatment: Device: Passive prosthesis; Device: Motorized prosthesis

Detailed Description

Participants will perform ambulation activities (see list below) while using their prescribed prosthesis or the motorized prosthesis in conjunction with their prescribed passive prosthesis. Each ambulation activity will be tested in four different conditions:

1. Ambulation with their personal (take home) device. This condition acts as a baseline to which the ambulation with the motorized prosthesis can be compared.
2. Ambulation with the motorized prosthesis in the "off" configuration (i.e., no power is applied to the motor). This condition demonstrates the impact of the device when it is unpowered.
3. Ambulation with the motorized prosthesis in the "transparent" configuration (i.e., minimal power is applied to the motor, such that the device behaves as a free hinge). This condition demonstrates the impact of the device when it behaves as a free hinge, similar to the participants personal device.
4. Ambulation with the motorized prosthesis in the "powered" configuration (i.e., substantial electrical power is applied to the motor to replicate the function of the biological joint). This condition assesses the impact of the motorized prosthesis to improve ambulation of the participant.

Trials will take place over-ground and/or on a treadmill. Participants will walk for up to 40 minutes. Frequent breaks will be provided between trials and conditions to avoid fatigue and a maximum of 15 minutes of continuous walking will take place between breaks. When deemed necessary by the research staff or participant, crutches, canes, walkers, an overhead support system, or other ambulation or safety aid will be used to minimize the risk of a severe fall.

List of ambulation activities

1. Walking at a mild incline/decline (0°-15°) on treadmill or over-ground
2. Ascending or descending stairs
3. Stand to sit and sit to stand transitions
4. All terrain walking over ground
5. Turning
6. Any combination of the above-mentioned activities

The above conditions will be assessed using motion capture techniques in the laboratory environment which will include measures of metabolic energy consumption and muscle activity.

All terrain walking over ground will take place on campus and include Engineering, Business, and Learning resource Center buildings, the north and south quads, and campus walkways and urban trails. During all terrain walking, the participant will be attended by research personnel that will monitor subject safety.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Dante A Archangeli, PhD; Phone Number: 928-421-3563; Email: dante.archangeli@nau.edu

Study Locations

• United States
  • Arizona
    • Flagstaff, Arizona, United States, 86001
      • Northern Arizona University
      • Contact: Dante A Archangeli, PhD; Phone Number: 928-421-3563; Email: dante.archangeli@nau.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Individuals age 18 to 85 with or without lower-limb amputation
• Able to understand and follow simple directions in English based on ability to provide verbal consent
• Able to walk at least 30 feet with or without a walking aid
• Able to safely fit into a device configuration and tolerate assistance
• Individuals with lower-limb amputation must receive physician approval to participate in the study.

Exclusion Criteria:

• Any neurological, musculoskeletal (other than lower-limb amputation) or cardiorespiratory injury, health condition (including pregnancy), or diagnosis that would affect the ability to walk as directed for short periods of time.
• Participant or caregiver report that the perspective participant's physician has recommended that they not engage in moderate intensity walking exercise.
• Subject mass greater than the engineered limit of the device (90 kg or 198 lbs) Note: No exclusions will be made on the basis of race, gender or ethnic background.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Experimental Group; Trials will take place over-ground and/or on a treadmill. Participants will ambulate for up to 40 minutes. Frequent breaks will be provided between trials and conditions to avoid fatigue and a maximum of 15 minutes of continuous ambulation will take place between breaks. When deemed necessary by the research staff or participant, crutches, canes, walkers, an overhead support system, or other ambulation or safety aid will be used to minimize the risk of a severe fall. List of ambulation activities will include no more than; Walking at a mild incline/decline (0°-15°) on treadmill or over-ground; Ascending or descending stairs; Stand to sit and sit to stand transitions; All terrain walking over ground; Turning; Any combination of the above-mentioned activities The above activities will be performed with the passive prosthesis and the motorized prosthesis in the "off", "transparent", and "powered" configurations.

Device: Passive prosthesis; The participant will perform the study protocol with their "take home" prosthesis and/or another suitable passive prosthesis.; Other Names: control; baseline; take home prosthesis; Device: Motorized prosthesis; The motorized prosthesis is an experimental device. The device is constructed from plastic and metal. It has motors, sensors, and electronic systems to control the prosthesis to mimic the behavior of a biological joint. The device is determined non-significant risk by the sponsor's Institutional Review Board.; Other Names: powered prosthesis

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Joint position	Motion capture measurements will be taken to calculate joint position (degrees) of the ankle, knee, hip, and torso. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)
Joint Velocity	Motion capture will be used to record joint velocity (deg/s) of the ankle, knee, hip, and torso. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)
Ground reaction force	The force a participant exerts on the ground (Newtons) will be measured using a force plate. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)
Muscle Electric Potential	Muscle electric potential will be measured using skin mounted electrodes (surface electromyography) and reported in volts. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)
Gas uptake and exchange	Oxygen consumption and CO2 production will be measured in L/s. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
User Perception	User perception of the device will be assessed using NASA TLX survey. Participants will assess the device on a scale of 1-10 based on a questionnaire. Participant measurements will be averaged per condition to generate a participant average. Participant averages will be pooled to determine an average per condition.	Assessment will be taken on Day 1 (Intervention 1), Day 2 (Intervention 2 - condition 1), Day 3 (Intervention 2 - condition 2), and Day 4 (Intervention 2 - condition 3)

Collaborators and Investigators

• Sponsor: Northern Arizona University

Study record dates

Study Major Dates

• Study Start (Estimated): April 16, 2026
• Primary Completion (Estimated): March 15, 2029
• Study Completion (Estimated): March 15, 2029

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: May 7, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: mobility; biomechanics; amputation; ambulation; motorized prosthesis
• Additional Relevant MeSH Terms: Health Care Quality, Access, and Evaluation; Investigative Techniques; Epidemiologic Methods; Data Collection; Health Care Evaluation Mechanisms; Quality of Health Care; Public Health; Environment and Public Health; Surveys and Questionnaires
• Other Study ID Numbers: 2403974-1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Uncertain if will publish in ICMJE journal

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No