Effects of Ankle Evertor Fatigue on Perturbed Gait

NCT ID: NCT07273097

Last Updated: 2025-12-09

Basic Information

• Recruitment Status: RECRUITING
• Total Enrollment: 40 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-05-05
• Study Completion Date: 2026-04-30

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.

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

Study Design

• Observational Model Type: CASE_CONTROL
• Study Time Perspective: CROSS_SECTIONAL

Study Groups

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.

Muscle fatigue

Intervention Type: 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

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.

Muscle fatigue

Intervention Type: 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.

Interventions

Muscle fatigue

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.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 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.

Exclusion Criteria

• Other pathologies of the ankle joint.
• Acute pain

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Ljubljana

OTHER

Sponsor Role: lead

Responsible Party

Alan Kacin

Head of Laboratory

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University Rehabilitation Institute Republic of Slovenia - URI Soča

Ljubljana, , Slovenia

Site Status: RECRUITING

Countries

Slovenia

Central Contacts

Alan Kacin, PhD, PT, Prof

Role: CONTACT

alan.kacin@zf.uni-lj.si

+38613001119

Tjaž Brezovar

Role: CONTACT

tjaz.brezovar@zf.uni-lj.si

+38640777919

Facility Contacts

Urška Puh, PhD, PT, Assoc. Prof

Role: primary

urska.puh@ir-rs.si

+38640577131

Other Identifiers

0120-197/2023/3/gait

Identifier Type: -

Identifier Source: org_study_id