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Updated: Sep 27, 2025
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Paradigms of Lower Extremity Electrical Stimulation Training After Spinal Cord Injury
Published on: February 1, 2018
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OIDA: An optimal interval detection algorithm for automatized determination of stimulation patterns for FES-Cycling
Martin Schmoll1, Ronan Le Guillou2, Charles Fattal3
1INRIA-Université de Montpellier, Montpellier, France. martin.schmoll@meduniwien.ac.at.
Journal of Neuroengineering and Rehabilitation
|April 15, 2022
Summary
This study introduces an algorithm for Functional Electrical Stimulation-Cycling (FES-Cycling) that automatically determines optimal muscle stimulation timing using torque feedback. This method improves pedaling quality and reduces setup time for individuals with spinal cord injury.
Area of Science:
- Biomedical Engineering
- Rehabilitation Technology
- Neuroscience
Background:
- Functional Electrical Stimulation-Cycling (FES-Cycling) enables individuals with spinal cord injury (SCI) or stroke to exercise paralyzed muscles.
- Effective FES-Cycling requires precise activation of the correct muscles at the optimal time.
- Current methods for determining stimulation patterns are often empirical and time-consuming.
Purpose of the Study:
- To develop and validate an algorithm for automatically determining optimal muscle stimulation intervals for FES-Cycling.
- To utilize torque feedback from a crank power-meter for real-time adjustment of stimulation patterns.
- To enable mobile FES-Cycling applications by not relying on constant angular velocity.
Main Methods:
- An algorithm was developed to analyze the difference between active (stimulated) and passive torques during pedaling.
- Torque feedback from a crank power-meter on a modified trike was used to identify muscle contribution phases.
- Stimulation patterns were automatically determined using crank-angle and normalized thigh-angle (via IMUs) in a subject with complete SCI.
Main Results:
- The algorithm successfully identified individual stimulation intervals for quadriceps and hamstring muscles bilaterally.
- Smooth cycling was achieved without additional adaptation for both crank-angle and normalized thigh-angle input modalities.
- The system demonstrated functionality without requiring a motor-driven constant angular velocity.
Conclusions:
- Automatic determination of FES-Cycling stimulation patterns based on net-positive torque can shorten setup duration and enhance pedaling quality.
- The algorithm's independence from constant angular velocity makes it suitable for mobile FES-Cycling systems.
- This approach can facilitate the evaluation of new electrode configurations, potentially boosting FES-Cycling performance.
