NCT07273097

Effects of Ankle Evertor Fatigue on Perturbed Gait

Effects of Ankle Evertor Fatigue on Gait Perturbation Responses in Individuals With and Without Chronic Ankle Instability

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 40 (estimated)
• Sponsor: University of Ljubljana · Academic / Other
• Sex: All
• Age: 18 Years – 45 Years
• Healthy volunteers: Accepted

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

Interventions

Type	Name	Description
OTHER	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.

Timeline

• Start date: 2025-05-05
• Primary completion: 2026-02-01
• Completion: 2026-04-01
• First posted: 2025-12-09
• Last updated: 2025-12-09

Locations

1 site across 1 country: Slovenia