Effects of Ankle Evertor Fatigue on Force Sense and Neuromuscular Activation in Subjects With Chronic Ankle Instability

NCT ID: NCT07252219

Last Updated: 2025-11-26

Basic Information

• Recruitment Status: RECRUITING
• Total Enrollment: 50 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-05-15
• Study Completion Date: 2026-03-31

Brief 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 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.

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 will complete the same experimental protocol as the group of chronic ankle instability, including a fatigue protocol of the ankle evertors

No interventions assigned to this group

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.

No interventions assigned to this group

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.

• 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

Faculty of Health Sciences

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

Martina Oder, PhD, Dean

Role: primary

martina.oder@zf.uni-lj.si

+38613001112

Other Identifiers

0120-197/2023/3/isokinetic

Identifier Type: -

Identifier Source: org_study_id