Effects of Ankle Evertor Fatigue on Perturbed Gait

NCT07273097 | Recruiting

• 1 other identifier: 0120-197/2023/3/gait
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Chronic Ankle Instability, CAI

Keywords

perturbed walking; fatigue; treadmill

Outcome Measures

Primary Outcomes (2)

• 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.

  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).

  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

  Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).

• Ground reaction forces (GRF)

  Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).

• Ratings of perceived exertion

  Baseline (Day 1, prior to fatigue protocol) and immediately post-fatigue (Day 1, within 5 minutes after fatigue protocol).

Study Arms (2)

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.

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.

Other: Muscle fatigue

Interventions

Muscle fatigue OTHER

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.

Chronic ankle instability group; Healthy group

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Participants will be recruited by convenience sampling from the general population and clinical settings.

You may qualify if:

• 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
• 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.

You may not qualify if:

• Other pathologies of the ankle joint.
• Acute pain

Sponsors & Collaborators

• University of Ljubljana: lead

Study Sites (1)

University Rehabilitation Institute Republic of Slovenia - URI Soča

Ljubljana, 1000, Slovenia

RECRUITING

MeSH Terms

Conditions

Fatigue

Interventions

Muscle Fatigue

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Central Study Contacts

Alan Kacin, PhD, PT, Prof

CONTACT

+38613001119; alan.kacin@zf.uni-lj.si

Tjaž Brezovar

CONTACT

+38640777919; tjaz.brezovar@zf.uni-lj.si

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of Laboratory

Study Record Dates

• First Submitted: November 26, 2025
• First Posted: December 9, 2025
• Study Start: May 5, 2025
• Primary Completion: April 23, 2026
• Study Completion: May 6, 2026
• Last Updated: April 29, 2026

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: No limit.
• Access Criteria: All IPD will be shared upon reasoned request for the purpose of further scientific analysis (i.e. systematic reviews, meta-analyzes, etc.). A proposal describing the planned analyzes must be submitted in writing to the principal investigator, Dr. Alan Kacin, by email to alan.kacin@zf.uni-lj.si.

Locations

SL (1)