Controlling Locomotion Over Continuously Varying Activities for Agile Powered Prosthetic Legs
1 other identifier
interventional
40
1 country
1
Brief Summary
The overall goal of this project is to model human joint biomechanics over continuously-varying locomotion to enable adaptive control of powered above-knee prostheses. The central hypothesis of this project is that variable joint impedance can be parameterized by a continuous model based on measurable quantities called phase and task variables. This project will use machine learning to identify variable impedance functions from able-bodied data including joint perturbation responses across the phase/task space to bias the solution toward biological values.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for not_applicable
Started Dec 2023
Longer than P75 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
November 13, 2023
CompletedFirst Posted
Study publicly available on registry
November 18, 2023
CompletedStudy Start
First participant enrolled
December 6, 2023
CompletedPrimary Completion
Last participant's last visit for primary outcome
January 30, 2028
ExpectedStudy Completion
Last participant's last visit for all outcomes
January 30, 2028
February 13, 2026
February 1, 2026
4.2 years
November 13, 2023
February 10, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (3)
Joint work
Mechanical work at the prosthetic knee and ankle will be assessed for participants using the powered prosthesis in A1.3 and A2.3, with comparisons to able-bodied averages. Joint work will be calculated by multiplying the joint's commanded torque by its measured velocity, resulting in units of Joules.
1 day
Tuning time
The time for a prosthetist to configure the powered prosthesis for above-knee amputee participants will be assessed in A3.1 and A3.3.
1 day
Endurance test time
The time to complete multiple cycles through an ambulation circuit will be recorded with above-knee amputee participants' take-home prosthesis and a powered prosthesis. The ambulation circuit comprises, sit-to-stand, walking, stair ascent/descent, ramp descent/ascent, and stand-to-sit.
1 day
Secondary Outcomes (6)
Inter-leg symmetry
1 day
Stance-swing time ratio
1 day
Step time symmetry
1 day
Step length symmetry
1 day
Step width symmetry
1 day
- +1 more secondary outcomes
Study Arms (1)
Prosthesis
EXPERIMENTALParticipants in this arm of the study will perform various tasks while wearing the powered prosthesis
Interventions
A powered prosthesis will be used to restore normative leg biomechanics to above-knee amputee participants during different activities of daily life.
Eligibility Criteria
You may qualify if:
- Aged between 18 to 65 years
You may not qualify if:
- Pregnant (self-report)
- Any significant neuromuscular or musculoskeletal disorder that would interfere with the study
- Unable to walk for 20 minutes
- History of any cardiovascular, vestibular, or visual diseases and/or impairments that may interfere with the study
- Cognitive deficits that would impair their ability to give informed consent or impair their ability to follow simple instructions during the experiments. In the case of screening for cognitive deficits, the consenting researcher will ask the subject if he/she has any prior history of cognitive deficits.
- Adults with a known allergy to medical grade tape
- Aged between 18 to 70 years.
- Weigh less than 250 lbs due to limitations in the design of the prosthesis.
- Amputee subjects will be more than two months post independent ambulation with an amputation at the transfemoral level in order to use the above-knee prosthesis.
- Amputee subjects will have a mobility classification of K2/K3/K4 ambulators (minimum community ambulatory) and have the ability to ambulate without an assistive device beyond their prosthesis.
- Weigh over 250 pounds body
- Pregnant (self-report)
- Any significant neuromuscular or musculoskeletal disorder that would interfere with the study
- Inactive or physically unfit, unable to walk for 20 minutes
- An excessively long residual limb length, and/or a non-removable cosmetic cover determined by the prosthetist performing the evaluations
- +4 more criteria
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Rehab Lab, University of Michigan
Ann Arbor, Michigan, 48109, United States
Related Publications (1)
Best TK, Seelhoff CA, Wensman J, Gregg RD. The clinical effects of the Ossur Power Knee with phase-based and default control during sitting, standing, and walking. J Neuroeng Rehabil. 2025 Sep 29;22(1):200. doi: 10.1186/s12984-025-01729-2.
PMID: 41024213DERIVED
Study Officials
- PRINCIPAL INVESTIGATOR
Robert D Gregg, PhD
University of Michigan
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- NA
- Masking
- NONE
- Purpose
- OTHER
- Intervention Model
- SINGLE GROUP
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Associate Professor of Robotics, Associate Professor of Electrical Engineering and Computer Science and Associate Professor of Mechanical Engineering, College of Engineering
Study Record Dates
First Submitted
November 13, 2023
First Posted
November 18, 2023
Study Start
December 6, 2023
Primary Completion (Estimated)
January 30, 2028
Study Completion (Estimated)
January 30, 2028
Last Updated
February 13, 2026
Record last verified: 2026-02
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL
De-identified IPD will be shared upon publication.