Muscle FatigueBiciFESNCT07873424
Recumbent Cycling and Functional Electrical Stimulation for Lower Limb Rehabilitation
A study of Muscle Fatigue and Functional Electrical Stimulation, run by National Council of Scientific and Technical Research, Argentina at 1 site in Argentina.
Trial summary
This study evaluates two different control strategies for a rehabilitation device that combines recumbent leg-cycling with functional electrical stimulation (FES) of the quadriceps muscle. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Muscle Fatigue, Functional Electrical Stimulation, Neuromuscular Rehabilitation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteArgentina
- Study dates
- 20 Aug 2026to 30 Nov 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age between 18 and 60 years.
- Body weight less than 120 kg.
- No injuries or conditions affecting the osteoarticular or musculoskeletal system.
- No strenuous physical exertion of the lower limb within the previous 24 hours.
- Willingness and ability to understand the content and scope of the experiment and to comply with its instructions.
- Signed informed consent.
Who cannot join
- Pregnancy.
- History of chronic pain, neuromuscular disorders, or lower-limb surgical interventions without medical clearance.
- Use of analgesics within 24 hours prior to participation.
- Lack of cooperation.
- Trauma to the segment under evaluation within the previous 4 weeks.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Argentina1 site, 1 recruiting
- Recruiting
Facultad de Ingeniería - Universidad Nacional de Entre Ríos
Oro Verde, Entre Ríos Province, 3100
Esteban Osella, PhD, (+54) 343 4975100 ext. 121, esteban.osella@uner.edu.ar
Carolina Chaves, MSc
About this study
Official title: Rehabilitation Mechanisms Based on Recumbent Pedaling and Functional Electrical Stimulation
This study evaluates two different control strategies for a rehabilitation device that combines recumbent leg-cycling with functional electrical stimulation (FES) of the quadriceps muscle. The device assists pedaling using a motor and electrical stimulation, and is intended for use after knee surgery (such as ACL reconstruction) or in other lower-limb rehabilitation. During muscle stimulation, fatigue can develop, which reduces the force produced by the stimulated muscle. This study compares a standard control strategy with a new strategy that adjusts stimulation based on the muscle's fatigue level, measured in real time. Healthy adult volunteers will complete two sessions on a recumbent stationary bicycle, 2 to 7 days apart. Each session lasts about 60 minutes and includes periods of pedaling with electrical stimulation, as well as isometric wall squats to induce muscle fatigue. Muscle activity, pedal force, and pedal position will be recorded throughout. The goal is to determine which control strategy produces more mechanical work from the leg muscles and better tracks the desired pedaling pattern, especially as fatigue develops.
Read the detailed description
The study uses a custom-instrumented recumbent stationary bicycle equipped with a brushless DC motor coupled to the pedal axis, load cells to measure pedal force, a Hall-effect sensor to measure pedal angular position, and a functional electrical stimulation (FES) system targeting the quadriceps femoris of the dominant leg. Surface electromyography (sEMG) is recorded using a 16-channel wireless system to estimate muscle fatigue in real time.
The study uses a randomized crossover design. Each participant completes both control strategies (with and without fatigue feedback) in randomized order across two separate sessions, 2 to 7 days apart, under similar physical and time-of-day conditions. Each session includes: a calibration phase (free pedaling without stimulation, followed by stimulation threshold testing); a first FES-assisted pedaling block; an isometric fatigue-induction phase (five wall squats); and a second FES-assisted pedaling block.
The primary outcome is the mechanical work performed during pedaling while under stimulation, measured in joules. Secondary outcomes include pedal force, muscle electrical activity (EMG RMS), muscle fatigue (estimated from pedal force variation and M-wave median frequency shift), and cadence-tracking error. The study is being conducted at the Biomechanics Laboratory, Facultad de Ingeniería, Universidad Nacional de Entre Ríos (Oro Verde, Entre Ríos, Argentina).
- Being tested
- Fatigue-Feedback FES Control Strategy, Standard FES Control Strategy
- Keywords
- FES Cycling, Muscle Fatigue, Closed-loop Control, Electromyography, Lower Limb Rehabilitation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fatigue-Feedback FES Control StrategyDevice
A closed-loop control strategy for the FES-assisted recumbent cycling device that explicitly incorporates real-time estimation of muscle fatigue (based on pedal force variation and M-wave median frequency) into the calculation of motor and electrical stimulation control signals.
Standard FES Control StrategyDevice
A closed-loop control strategy for the FES-assisted recumbent cycling device based on a previously published approach, without explicit real-time incorporation of muscle fatigue estimation into the control signal calculation.
| Study group | Role | What they receive |
|---|---|---|
| Fatigue-Feedback Control First | Experimental | Participants perform recumbent cycling with FES assistance using the fatigue-feedback control strategy in the first session, followed by the standard control strategy in the second session, 2 to 7 days later. Session order of strategies is randomized across participants. Receives: Device: Fatigue-Feedback FES Control Strategy; Device: Standard FES Control Strategy |
| Standard Control First | Active comparator | Participants perform recumbent cycling with FES assistance using the standard control strategy in the first session, followed by the fatigue-feedback control strategy in the second session, 2 to 7 days later. Session order of strategies is randomized across participants. Receives: Device: Fatigue-Feedback FES Control Strategy; Device: Standard FES Control Strategy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mechanical work performed during FES-assisted pedaling
Mechanical work performed by the stimulated lower limb during FES-assisted pedaling, in joules. Computed from pedal force (load cells) and pedal angular position, integrated over the stimulated regions of the pedaling cycle. Measured during the FES pedaling blocks before and after the isometric fatigue-induction phase, and compared between control strategies within each participant.
Measured: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Secondary outcomes (4)
Pedal force
Force applied to the pedals, in newtons, recorded with compression load cells mounted on the pedal platforms during the FES pedaling blocks before and after the isometric fatigue-induction phase.
Measured: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Muscle electrical activity (EMG RMS)
Muscle electrical activity quantified as the root mean square (RMS) value computed from the surface electromyography signal of the stimulated and contralateral muscles.
Measured: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Muscle fatigue
Muscle fatigue estimated from the variation in pedal force and from the shift in median frequency of the M-wave obtained from the surface electromyography signal.
Measured: Day 1 (Session 1) and Day 3 to Day 8 (Session 2), before and after the isometric fatigue-induction phase
Cadence tracking error
Error between the target pedaling cadence reference and the cadence actually achieved during FES-assisted pedaling.
Measured: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Oct 2026
- Study start20 Aug 2026
- Primary completion30 Oct 2026 (estimated)
- Study completion30 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Muscle FatigueStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Council of Scientific and Technical Research, Argentina
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Carolina Chaves García, National Council of Scientific and Technical Research, Argentina
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07873424
- Sponsor's protocol ID
- PICT 2018 - 33007
- Other IDs
- IS005275
- Acronym
- BiciFES
- Status last verified
- Oct 2026
- First submitted
- 30 Sep 2026
- Last updated
- 14 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
van Melick N, van Cingel RE, Brooijmans F, Neeter C, van Tienen T, Hullegie W, Nijhuis-van der Sanden MW. Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. Br J Sports Med. 2016 Dec;50(24):1506-1515. doi: 10.1136/bjsports-2015-095898. Epub 2016 Aug 18.
PubMed 27539507Chesler NC, Durfee WK. Surface EMG as a fatigue indicator during FES-induced isometric muscle contractions. J Electromyogr Kinesiol. 1997 Mar;7(1):27-37. doi: 10.1016/s1050-6411(96)00016-8.
PubMed 20719689C. A. Rouse, C. A. Cousin, B. C. Allen, and W. E. Dixon, "Shared control for switched motorized FES cycling on a split-crank cycle accounting for muscle control input saturation," Automatica, vol. 123, p. 109294, Jan. 2021.
Study at a glance
From the registry record, last updated by the sponsor on 14 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Rehabilitation Mechanisms Based on Recumbent Pedaling and Functional Electrical Stimulation
- ClinicalTrials.gov ID
- NCT07873424
- Acronym / sponsor ID
- BiciFES / PICT 2018 - 33007
- Keywords
- FES Cycling, Muscle Fatigue, Closed-loop Control, Electromyography, Lower Limb Rehabilitation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- National Council of Scientific and Technical Research, ArgentinaOther government
- Study start
- 20 Aug 2026 (actual)
- Primary completion
- 30 Oct 2026 (estimated)
- Study completion
- 30 Nov 2026 (estimated)
- First posted
- 14 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluates two different control strategies for a rehabilitation device that combines recumbent leg-cycling with functional electrical stimulation (FES) of the quadriceps muscle. The device assists pedaling using a motor and electrical stimulation, and is intended for use after knee surgery (such as ACL reconstruction) or in other lower-limb rehabilitation. During muscle stimulation, fatigue can develop, which reduces the force produced by the stimulated muscle. This study compares a standard control strategy with a new strategy that adjusts stimulation based on the muscle's fatigue level, measured in real time. Healthy adult volunteers will complete two sessions on a recumbent stationary bicycle, 2 to 7 days apart. Each session lasts about 60 minutes and includes periods of pedaling with electrical stimulation, as well as isometric wall squats to induce muscle fatigue. Muscle activity, pedal force, and pedal position will be recorded throughout. The goal is to determine which control strategy produces more mechanical work from the leg muscles and better tracks the desired pedaling pattern, especially as fatigue develops.
Detailed description
The study uses a custom-instrumented recumbent stationary bicycle equipped with a brushless DC motor coupled to the pedal axis, load cells to measure pedal force, a Hall-effect sensor to measure pedal angular position, and a functional electrical stimulation (FES) system targeting the quadriceps femoris of the dominant leg. Surface electromyography (sEMG) is recorded using a 16-channel wireless system to estimate muscle fatigue in real time.
The study uses a randomized crossover design. Each participant completes both control strategies (with and without fatigue feedback) in randomized order across two separate sessions, 2 to 7 days apart, under similar physical and time-of-day conditions. Each session includes: a calibration phase (free pedaling without stimulation, followed by stimulation threshold testing); a first FES-assisted pedaling block; an isometric fatigue-induction phase (five wall squats); and a second FES-assisted pedaling block.
The primary outcome is the mechanical work performed during pedaling while under stimulation, measured in joules. Secondary outcomes include pedal force, muscle electrical activity (EMG RMS), muscle fatigue (estimated from pedal force variation and M-wave median frequency shift), and cadence-tracking error. The study is being conducted at the Biomechanics Laboratory, Facultad de Ingeniería, Universidad Nacional de Entre Ríos (Oro Verde, Entre Ríos, Argentina).
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Fatigue-Feedback Control First | Experimental | Device: Fatigue-Feedback FES Control Strategy, Device: Standard FES Control StrategyParticipants perform recumbent cycling with FES assistance using the fatigue-feedback control strategy in the first session, followed by the standard control strategy in the second session, 2 to 7 days later. Session order of strategies is randomized across participants. |
| Standard Control First | Active comparator | Device: Fatigue-Feedback FES Control Strategy, Device: Standard FES Control StrategyParticipants perform recumbent cycling with FES assistance using the standard control strategy in the first session, followed by the fatigue-feedback control strategy in the second session, 2 to 7 days later. Session order of strategies is randomized across participants. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Age between 18 and 60 years.
- Body weight less than 120 kg.
- No injuries or conditions affecting the osteoarticular or musculoskeletal system.
- No strenuous physical exertion of the lower limb within the previous 24 hours.
- Willingness and ability to understand the content and scope of the experiment and to comply with its instructions.
Key exclusion criteria (5 listed)
- Pregnancy.
- History of chronic pain, neuromuscular disorders, or lower-limb surgical interventions without medical clearance.
- Use of analgesics within 24 hours prior to participation.
- Lack of cooperation.
- Trauma to the segment under evaluation within the previous 4 weeks.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fatigue-Feedback FES Control StrategyA closed-loop control strategy for the FES-assisted recumbent cycling device that explicitly incorporates real-time estimation of muscle fatigue (based on pedal force variation and M-wave median frequency) into the calculation of motor and electrical stimulation control signals. | Device | Fatigue-Feedback Control First, Standard Control First |
| Standard FES Control StrategyA closed-loop control strategy for the FES-assisted recumbent cycling device based on a previously published approach, without explicit real-time incorporation of muscle fatigue estimation into the control signal calculation. | Device | Fatigue-Feedback Control First, Standard Control First |
Primary outcome
Mechanical work performed during FES-assisted pedaling
Time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Mechanical work performed by the stimulated lower limb during FES-assisted pedaling, in joules. Computed from pedal force (load cells) and pedal angular position, integrated over the stimulated regions of the pedaling cycle. Measured during the FES pedaling blocks before and after the isometric fatigue-induction phase, and compared between control strategies within each participant.
4 secondary outcomes
Pedal force
Time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Muscle electrical activity (EMG RMS)
Time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Muscle fatigue
Time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2), before and after the isometric fatigue-induction phase
Cadence tracking error
Time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Oct 2026.
- Background: PubMed 27539507van Melick N, van Cingel RE, Brooijmans F, Neeter C, van Tienen T, Hullegie W, Nijhuis-van der Sanden MW. Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. Br J Sports Med. 2016 Dec;50(24):1506-1515. doi: 10.1136/bjsports-2015-095898. Epub 2016 Aug 18.
- Background: PubMed 20719689Chesler NC, Durfee WK. Surface EMG as a fatigue indicator during FES-induced isometric muscle contractions. J Electromyogr Kinesiol. 1997 Mar;7(1):27-37. doi: 10.1016/s1050-6411(96)00016-8.
- BackgroundC. A. Rouse, C. A. Cousin, B. C. Allen, and W. E. Dixon, "Shared control for switched motorized FES cycling on a split-crank cycle accounting for muscle control input saturation," Automatica, vol. 123, p. 109294, Jan. 2021.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study of Muscle Fatigue and Functional Electrical Stimulation, run by National Council of Scientific and Technical Research, Argentina at 1 site in Argentina.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 14 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Argentina. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Carolina Chaves García, MSc ((+54) 343 4975100 ext. 121, carolina.chaves@uner.edu.ar), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mechanical work performed during FES-assisted pedaling (time frame: Day 1 (Session 1) and Day 3 to Day 8 (Session 2)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07873424, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Oct 2026; AzTrials last refreshed its copy on 7 Nov 2026.