Chronic Ankle Instability, CAINCT07273097
Effects of Ankle Evertor Fatigue on Perturbed Gait
An observational study of Chronic Ankle Instability, CAI, run by University of Ljubljana at 1 site in Slovenia.
Trial summary
This study will investigate the effects of ankle evertor muscle fatigue on gait stability during treadmill walking with mechanical perturbations. Participants will walk at two speeds (0.4 m/s and 1.0 m/s) while random medial and lateral perturbations (<10% body weight) are applied to the pelvis. 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
- What is being tested?
- Muscle fatigue
- How many people
- 58 participants
- Where
- 1 siteSlovenia
- Study dates
- 5 May 2025to 6 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.
- Acute pain
Trial locations and contacts
1 site in 1 country.
Slovenia1 site
University Rehabilitation Institute Republic of Slovenia - URI Soča
Ljubljana, 1000
About this study
Official title: Effects of Ankle Evertor Fatigue on Gait Perturbation Responses in Individuals With and Without Chronic Ankle Instability
This study will investigate the effects of ankle evertor muscle fatigue on gait stability during treadmill walking with mechanical perturbations. Participants will walk at two speeds (0.4 m/s and 1.0 m/s) while random medial and lateral perturbations (<10% body weight) are applied to the pelvis. Surface EMG from ankle muscles and center of pressure (COP)-based gait parameters (e.g., step length, step width, single support duration, COP trajectory) will be analyzed before and immediately after an isotonic fatigue protocol of the ankle evertors.
Read the detailed description
The purpose of this study is to examine how ankle evertor muscle fatigue affects gait stability and neuromuscular responses during treadmill walking with mechanical perturbations. Perturbations will be applied randomly in the medial or lateral direction, but always shortly after initial foot contact, to specifically challenge ankle stabilization in stance.
The study will include individuals with chronic ankle instability (CAI) and matched healthy controls. In the CAI group, the symptomatic side will be targeted with the fatigue protocol, whereas in healthy controls the tested side will be assigned to match the distribution of sprain laterality in the CAI group.
Walking and perturbation protocol:
Participants will first complete familiarization at 1.0 m/s, including both normal and perturbed walking. After familiarization, the measurements will consist of 2 minutes of unperturbed walking followed by 3 minutes of perturbed walking. The same procedure will then be repeated at 0.4 m/s, with familiarization (normal and perturbed walking) preceding the measurement block.
The fatigue protocol will be applied immediately after these baseline blocks. Following fatigue, participants will immediately perform perturbed walking at 1.0 m/s. The fatigue protocol will then be repeated, followed by perturbed walking at 0.4 m/s.
Fatigue protocol:
Ankle evertor muscles will be fatigued using elastic resistance bands through repeated concentric and eccentric eversion contractions. The task will be paced using a metronome at a rate of one repetition per second, and will continue until the active eversion range of motion decreases by 50% compared to baseline.
- Conditions
- Chronic Ankle Instability, CAI
- Being tested
- Muscle fatigue
- Keywords
- perturbed walking, fatigue, treadmill
- Medical subject headings
- Fatigue
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Muscle fatigueOther
The fatigue protocol will consist of repeated concentric-eccentric ankle eversion contractions against elastic resistance at a pace of one repetition per second, guided by a metronome, and performed in a seated position. Fatigue will be defined as a clear inability to perform the full range of eversion, i.e. the range of motion falling below 50% of the initial value despite evident effort by the participant.
| Study group | Role | What they receive |
|---|---|---|
| Healthy group | Healthy participants without a history of ankle sprain or self-reported ankle instability. Participants in this group will complete the same experimental protocol as Chronic ankle instability group, which includes treadmill walking at two speeds (0.4 m/s and 1.0 m/s) with and without mechanical perturbations, performed before and after an ankle evertor fatigue protocol. For this group, the fatigued limb will be assigned based on the laterality of ankle sprains observed in the CAI group. Receives: Other: Muscle fatigue | |
| Chronic ankle instability group | Participants with chronic ankle instability, defined by a history of recurrent ankle sprains and self-reported instability. Participants in this group will complete the same experimental protocol as Healthy group, which includes treadmill walking at two speeds (0.4 m/s and 1.0 m/s) with and without mechanical perturbations, performed before and after an ankle evertor fatigue protocol. For this group, the fatigued limb will be the symptomatic side. Receives: Other: Muscle fatigue |
What is being measured
The primary outcome is the main question the study is designed to answer.
Surface EMG root mean square (RMS) amplitude of ankle muscles
Surface EMG RMS amplitude from peroneus longus (PL), tibialis anterior (TA), soleus (SOL), gastrocnemius medialis (GM), and gluteus medius (GMed), recorded bilaterally during treadmill walking. EMG will be time-normalized to the gait cycle (0-100%). The primary epoch is the perturbation step (shortly after initial contact through stance). For each muscle and speed, EMG during perturbed walking will be normalized to matched unperturbed walking.
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Center of Pressure mediolateral displacement (COPx)
Mediolateral displacement of the center of pressure (COPx) during walking, time-normalized to the gait cycle (0-100%). In addition, COPx will be expressed relative to the sacral marker (COPx-SACRx). Values will be presented in absolute units (cm) and compared between matched perturbed steps at the same walking speed (before and after fatigue).
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Secondary outcomes (3)
Step Length and width
Step length (heel-to-heel) and step width of the perturbation step, derived from 3D motion capture with reflective markers placed on anatomical landmarks. Both parameters will be compared against matched unperturbed steps.
Measured: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Ground reaction forces (GRF)
Vertical GRF (Fz; peak, mean, loading rate), with optional analysis of anteroposterior (Fy) and mediolateral (Fx) components, time-normalized to the gait cycle (0-100%). Values reported in absolute units (N for forces; N/s for loading rate).
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 posted9 Dec 2025
- Study start5 May 2025
- Primary completion23 Apr 2026
- Study completion6 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
- 58 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
- NCT07273097
- Sponsor's protocol ID
- 0120-197/2023/3/gait
- Status last verified
- Oct 2026
- First submitted
- 26 Nov 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 Gait Perturbation Responses in Individuals With and Without Chronic Ankle Instability
- ClinicalTrials.gov ID
- NCT07273097
- Acronym / sponsor ID
- 0120-197/2023/3/gait
- Conditions
- Chronic Ankle Instability, CAI
- Keywords
- perturbed walking, fatigue, treadmill
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 58 participants (actual)
- Lead sponsor
- University of LjubljanaUniversity, hospital or other
- Study start
- 5 May 2025 (actual)
- Primary completion
- 23 Apr 2026 (actual)
- Study completion
- 6 May 2026 (actual)
- First posted
- 9 Dec 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.
This study will investigate the effects of ankle evertor muscle fatigue on gait stability during treadmill walking with mechanical perturbations. Participants will walk at two speeds (0.4 m/s and 1.0 m/s) while random medial and lateral perturbations (<10% body weight) are applied to the pelvis. Surface EMG from ankle muscles and center of pressure (COP)-based gait parameters (e.g., step length, step width, single support duration, COP trajectory) will be analyzed before and immediately after an isotonic fatigue protocol of the ankle evertors.
Detailed description
The purpose of this study is to examine how ankle evertor muscle fatigue affects gait stability and neuromuscular responses during treadmill walking with mechanical perturbations. Perturbations will be applied randomly in the medial or lateral direction, but always shortly after initial foot contact, to specifically challenge ankle stabilization in stance.
The study will include individuals with chronic ankle instability (CAI) and matched healthy controls. In the CAI group, the symptomatic side will be targeted with the fatigue protocol, whereas in healthy controls the tested side will be assigned to match the distribution of sprain laterality in the CAI group.
Walking and perturbation protocol:
Participants will first complete familiarization at 1.0 m/s, including both normal and perturbed walking. After familiarization, the measurements will consist of 2 minutes of unperturbed walking followed by 3 minutes of perturbed walking. The same procedure will then be repeated at 0.4 m/s, with familiarization (normal and perturbed walking) preceding the measurement block.
The fatigue protocol will be applied immediately after these baseline blocks. Following fatigue, participants will immediately perform perturbed walking at 1.0 m/s. The fatigue protocol will then be repeated, followed by perturbed walking at 0.4 m/s.
Fatigue protocol:
Ankle evertor muscles will be fatigued using elastic resistance bands through repeated concentric and eccentric eversion contractions. The task will be paced using a metronome at a rate of one repetition per second, and will continue until the active eversion range of motion decreases by 50% compared to baseline.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Healthy group | – | Other: Muscle fatigueHealthy participants without a history of ankle sprain or self-reported ankle instability. Participants in this group will complete the same experimental protocol as Chronic ankle instability group, which includes treadmill walking at two speeds (0.4 m/s and 1.0 m/s) with and without mechanical perturbations, performed before and after an ankle evertor fatigue protocol. For this group, the fatigued limb will be assigned based on the laterality of ankle sprains observed in the CAI group. |
| Chronic ankle instability group | – | Other: Muscle fatigueParticipants with chronic ankle instability, defined by a history of recurrent ankle sprains and self-reported instability. Participants in this group will complete the same experimental protocol as Healthy group, which includes treadmill walking at two speeds (0.4 m/s and 1.0 m/s) with and without mechanical perturbations, performed before and after an ankle evertor fatigue protocol. For this group, the fatigued limb will be the symptomatic side. |
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 (2 listed)
- Other pathologies of the ankle joint.
- Acute pain
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 |
|---|---|---|
| Muscle fatigueThe fatigue protocol will consist of repeated concentric-eccentric ankle eversion contractions against elastic resistance at a pace of one repetition per second, guided by a metronome, and performed in a seated position. Fatigue will be defined as a clear inability to perform the full range of eversion, i.e. the range of motion falling below 50% of the initial value despite evident effort by the participant. | Other | Chronic ankle instability group, Healthy group |
Primary outcome
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 RMS amplitude from peroneus longus (PL), tibialis anterior (TA), soleus (SOL), gastrocnemius medialis (GM), and gluteus medius (GMed), recorded bilaterally during treadmill walking. EMG will be time-normalized to the gait cycle (0-100%). The primary epoch is the perturbation step (shortly after initial contact through stance). For each muscle and speed, EMG during perturbed walking will be normalized to matched unperturbed walking.
Center of Pressure mediolateral displacement (COPx)
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Mediolateral displacement of the center of pressure (COPx) during walking, time-normalized to the gait cycle (0-100%). In addition, COPx will be expressed relative to the sacral marker (COPx-SACRx). Values will be presented in absolute units (cm) and compared between matched perturbed steps at the same walking speed (before and after fatigue).
3 secondary outcomes
Step Length and width
Time frame: Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).
Ground reaction forces (GRF)
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.
Related trials for Chronic Ankle Instability, CAI
Recruiting
Neurocognitive Enrichment During Functional Performance Testing in Chronic Ankle Instability
Chronic Ankle Instability, CAI
Recruiting
Effects of Cervical and Oculomotor Exercises on Functional Status, Balance, and Proprioception in Chronic Ankle Instability
Chronic Ankle Instability, CAI
Recruiting
Ankle vs. Hip vs. Combined Strengthening in Chronic Ankle Instability
Chronic Ankle Instability, CAI, Ankle Sprain
Not yet recruiting
Lower Extremity Mobility for CAI
Chronic Ankle Instability, CAI
Not yet recruitingObservational study
The Effect of Cognitive Dual-Task on Athletic Performance Parameters in Volleyball Players With and Without Chronic Ankle Instability
Chronic Ankle Instability, Chronic Ankle Instability, CAI
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 2 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?
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).). The study lists 2 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; AzTrials last refreshed its copy on 7 Nov 2026.