Chronic Ankle Instability, CAINCT07252219
Effects of Ankle Evertor Fatigue on Force Sense and Neuromuscular Activation in Subjects With Chronic Ankle Instability
An observational study of Chronic Ankle Instability, CAI, run by University of Ljubljana at 1 site in Slovenia.
Trial summary
The goal of this observational study is to investigate whether ankle evertor muscle fatigue impairs force perception and alters neuromuscular activation patterns during submaximal isometric contractions, and whether these effects differ between individuals with chronic ankle instability (CAI) and individuals without… Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Chronic Ankle Instability, CAI
- How many people
- 50 participants
- Where
- 1 siteSlovenia
- Study dates
- 15 May 2025to 4 May 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
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 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Participants will be recruited by convenience sampling from the general population and clinical settings.
Who may be able to join
- Age between 18 and 45 years,
- No history of injuries or surgical procedures to the lower limbs,
- No peripheral or central neurological impairments.
- Inclusion criteria for the chronic ankle instability (CAI) group:
- Age between 18 and 45 years,
- No history of major surgical procedures on the lower limbs
Show all 11Show fewer
- No peripheral or central neurological impairments,
- Diagnosed chronic ankle instability:
- First ankle sprain occurred at least one year prior to testing,
- At least three months since the most recent ankle sprain,
- Subjective feeling of ankle instability - CAIT (Cumberland Ankle Instability Tool) score < 24.
Who cannot join
- Other pathologies of the ankle joint.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Ankle Evertor Fatigue on Force Sense and Neuromuscular Activation During Submaximal Isometric Contractions in Individuals With and Without Chronic Ankle Instability
The goal of this observational study is to investigate whether ankle evertor muscle fatigue impairs force perception and alters neuromuscular activation patterns during submaximal isometric contractions, and whether these effects differ between individuals with chronic ankle instability (CAI) and individuals without CAI.
Read the detailed description
Participants will first be familiarized with the research protocol for approximately 20 minutes. After a short break, the experimental protocol with data collection will begin and last between 45 and 60 minutes. Measurements will be performed on the side where the participant reports symptoms of chronic ankle instability. In cases of bilateral CAI, the leg with the lower CAIT score will be tested.
Participants will be tested on an isokinetic dynamometer (Humac Norm, CSMi, USA) in a semi-recumbent position with the hip and knee flexed to ensure comfort and alignment. The trunk and tested leg will be secured with straps to minimize accessory movement. After initial maximal voluntary isometric contraction (MVIC) of ankle evertors, participants will perform force-matching tasks at 25% and 50% of MVIC. Each trial will consist of 5 seconds with visual feedback followed by 5 seconds without feedback, repeated three times per intensity. After completing these tasks, participants will undergo a fatigue protocol for the ankle evertors. After the fatigue protocol, participants will repeat the force-matching tasks at both 25% and 50% MVIC.
The muscle fatigue protocol consists of consecutive isotonic contractions of ankle eversion, performed through the full range of motion at 30% of MVIC torque until visible fatigue. Fatigue will be defined as a clear inability to perform full range of eversion, i.e. the range of motion fell below 10% of the initial value despite evident effort by the participant. The test will be paced using a metronome, with a 1-second concentric and a 1-second eccentric phase to ensure consistent movement velocity.
- Conditions
- Chronic Ankle Instability, CAI
- Keywords
- chronic ankle instability, force sense, muscle fatigue, proprioception
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Healthy group | Healthy participants without a history of ankle sprain or self-reported ankle instability. Participants will complete the same experimental protocol as the group of chronic ankle instability, including a fatigue protocol of the ankle evertors | |
| Chronic ankle instability group | Participants with chronic ankle instability, defined by a history of recurrent ankle sprains and self-reported instability. Participants will complete the same experimental protocol as the control group, including a fatigue protocol of the ankle evertors. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Constant Error (CE)
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks.
Constant Error (CE) will be calculated as the mean difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level.
Unit of measure: Newton-meters (Nm).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Absolute Error (AE)
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks.
Absolute Error (AE) will be calculated as the mean absolute difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level.
Unit of measure: Newton-meters (Nm).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Variable Error (VE)
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks.
Variable Error (VE) will be calculated as the standard deviation of errors across three repetitions at each load level.
Unit of measure: Newton-meters (Nm).
Measured: Time Frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Coefficient of Variation (CV) of generated force
Ratio of the standard deviation to the mean force during the middle three seconds of sustained contraction in each trial, calculated separately for trials with and without visual feedback. Unit of Measure: Percentage (%).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Secondary outcomes (4)
Surface EMG root mean square (RMS) amplitude of ankle muscles
RMS amplitude from surface EMG signals of the peroneus longus, tibialis anterior, soleus, and gastrocnemius medialis will be obtained during the fatigue protocol, MVIC and force-matching task. Unit of Measure: millivolts (mV).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Surface EMG median frequency of peroneus longus mucle
Median frequency of EMG signals will be obtained from the peroneus longus during the fatigue protocol, the maximal voluntary isometric contraction (MVIC) and force-matching tasks. Frequency values will be averaged across repetitions. Unit of Measure: Hertz (Hz).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Maximal voluntary isometric contraction (MVIC)
MVIC of the ankle evertors will be measured at the beginning of the protocol to determine the target force for submaximal isometric contractions, and repeated immediately after the fatigue protocol to assess the effectiveness of fatigue, expressed in Newton-meters (Nm).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Ratings of perceived exertion
Description: Ratings of perceived exertion (RPE) will be assessed at the end of each fatigue protocol using the Borg 10 category-ratio scale, with 0 is no effort and 10 is an extreme physical effort.
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2025
- Study start15 May 2025
- Primary completion14 Apr 2026
- Study completion4 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Ankle Instability, CAIStudies 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
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 50 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Ljubljana
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Alan Kacin, University of Ljubljana
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07252219
- Sponsor's protocol ID
- 0120-197/2023/3/isokinetic
- Status last verified
- Oct 2026
- First submitted
- 10 Sep 2025
- Last updated
- 19 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All collected IPD in anonymized form.
Study at a glance
From the registry record, last updated by the sponsor on 19 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Ankle Evertor Fatigue on Force Sense and Neuromuscular Activation During Submaximal Isometric Contractions in Individuals With and Without Chronic Ankle Instability
- ClinicalTrials.gov ID
- NCT07252219
- Acronym / sponsor ID
- 0120-197/2023/3/isokinetic
- Conditions
- Chronic Ankle Instability, CAI
- Keywords
- chronic ankle instability, force sense, muscle fatigue, proprioception
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 50 participants (actual)
- Lead sponsor
- University of LjubljanaUniversity, hospital or other
- Study start
- 15 May 2025 (actual)
- Primary completion
- 14 Apr 2026 (actual)
- Study completion
- 4 May 2026 (actual)
- First posted
- 26 Nov 2025 (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.
The goal of this observational study is to investigate whether ankle evertor muscle fatigue impairs force perception and alters neuromuscular activation patterns during submaximal isometric contractions, and whether these effects differ between individuals with chronic ankle instability (CAI) and individuals without CAI.
Detailed description
Participants will first be familiarized with the research protocol for approximately 20 minutes. After a short break, the experimental protocol with data collection will begin and last between 45 and 60 minutes. Measurements will be performed on the side where the participant reports symptoms of chronic ankle instability. In cases of bilateral CAI, the leg with the lower CAIT score will be tested.
Participants will be tested on an isokinetic dynamometer (Humac Norm, CSMi, USA) in a semi-recumbent position with the hip and knee flexed to ensure comfort and alignment. The trunk and tested leg will be secured with straps to minimize accessory movement. After initial maximal voluntary isometric contraction (MVIC) of ankle evertors, participants will perform force-matching tasks at 25% and 50% of MVIC. Each trial will consist of 5 seconds with visual feedback followed by 5 seconds without feedback, repeated three times per intensity. After completing these tasks, participants will undergo a fatigue protocol for the ankle evertors. After the fatigue protocol, participants will repeat the force-matching tasks at both 25% and 50% MVIC.
The muscle fatigue protocol consists of consecutive isotonic contractions of ankle eversion, performed through the full range of motion at 30% of MVIC torque until visible fatigue. Fatigue will be defined as a clear inability to perform full range of eversion, i.e. the range of motion fell below 10% of the initial value despite evident effort by the participant. The test will be paced using a metronome, with a 1-second concentric and a 1-second eccentric phase to ensure consistent movement velocity.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Healthy group | – | –Healthy participants without a history of ankle sprain or self-reported ankle instability. Participants will complete the same experimental protocol as the group of chronic ankle instability, including a fatigue protocol of the ankle evertors |
| Chronic ankle instability group | – | –Participants with chronic ankle instability, defined by a history of recurrent ankle sprains and self-reported instability. Participants will complete the same experimental protocol as the control group, including a fatigue protocol of the ankle evertors. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Participants will be recruited by convenience sampling from the general population and clinical settings.
Key inclusion criteria (11 listed)
- Age between 18 and 45 years,
- No history of injuries or surgical procedures to the lower limbs,
- No peripheral or central neurological impairments.
- Age between 18 and 45 years,
- No history of major surgical procedures on the lower limbs
Key exclusion criteria (1 listed)
- Other pathologies of the ankle joint.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Constant Error (CE)
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Constant Error (CE) will be calculated as the mean difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level. Unit of measure: Newton-meters (Nm).
Absolute Error (AE)
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Absolute Error (AE) will be calculated as the mean absolute difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level. Unit of measure: Newton-meters (Nm).
Variable Error (VE)
Time frame: Time Frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Variable Error (VE) will be calculated as the standard deviation of errors across three repetitions at each load level. Unit of measure: Newton-meters (Nm).
Coefficient of Variation (CV) of generated force
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Ratio of the standard deviation to the mean force during the middle three seconds of sustained contraction in each trial, calculated separately for trials with and without visual feedback. Unit of Measure: Percentage (%).
4 secondary outcomes
Surface EMG root mean square (RMS) amplitude of ankle muscles
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Surface EMG median frequency of peroneus longus mucle
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Maximal voluntary isometric contraction (MVIC)
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Ratings of perceived exertion
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Oct 2026.
- Individual participant dataSharing planned: Yes. All collected IPD in anonymized form.
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Chronic Ankle Instability, CAI, run by University of Ljubljana at 1 site in Slovenia.
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 11 inclusion and 1 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: finished, as of the sponsor's last update on 19 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 Slovenia. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Constant Error (CE) (time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 19 Oct 2026.