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Updated: Sep 18, 2025
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Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
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Evaluation of a Portable Bionic Ankle Prosthesis Under Direct Continuous Electromyography Control for Quiet Standing
Nicole E Stafford1,2,3, Eddie B Gonzalez1,2,3, Daniel P Ferris1,2,3
1NICOLE E. STAFFORD, BS, MS, is affiliated with the Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida.
Journal of Prosthetics and Orthotics : JPO
|June 27, 2025
Summary
A bionic ankle prosthesis with myoelectric control did not significantly improve standing balance compared to passive prostheses in individuals with transtibial amputation. Further research may require different metrics to detect balance improvements.
Area of Science:
- Biomechanics and Motor Control
- Prosthetics and Orthotics
- Rehabilitation Engineering
Background:
- Postural control is crucial for daily activities, and passive prostheses can alter balance strategies.
- Powered prostheses offer potential for restoring ankle joint control and improving balance.
- Myoelectric control leverages the user's neural system to modulate prosthetic dynamics.
Purpose of the Study:
- To evaluate continuous myoelectric control of an untethered bionic ankle prosthesis during quiet standing.
- To compare balance control between a passive prosthesis and a myoelectrically controlled bionic prosthesis.
Main Methods:
- Six individuals with transtibial amputation performed quiet standing tasks under various conditions (eyes open/closed, foam surface).
- Balance was assessed using center of pressure measures (Total Excursion, Body Sway Area, Prediction Ellipse Area).
- Two myoelectric control strategies (GAS, GAS+TA) were tested, alongside a passive prosthesis.
Main Results:
- No significant differences in balance control measures were found between the passive and bionic prostheses across conditions.
- Participants increased weight-bearing on their sound limb in more challenging conditions (Eyes Closed Foam).
- A preference for myoelectric control was observed, but without statistically significant differences.
Conclusions:
- Myoelectrically controlled bionic transtibial prostheses did not demonstrate improved standing balance compared to passive prostheses.
- Current balance metrics may lack sensitivity to detect subtle improvements with bionic prostheses.
