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

NCT07252219 | Recruiting

• 1 other identifier: 0120-197/2023/3/isokinetic
• Study Type: observational
• Target: 50
• Locations: 1 country
• Sites: 1

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.

Conditions

Chronic Ankle Instability, CAI

Keywords

chronic ankle instability; force sense; muscle fatigue; proprioception

Outcome Measures

Primary Outcomes (4)

• Constant Error (CE)

  Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Constant Error (CE) will be calculated as the mean difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level. Unit of measure: Newton-meters (Nm).

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

• Absolute Error (AE)

  Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Absolute Error (AE) will be calculated as the mean absolute difference in force (Nm) between reproduction with and without visual feedback during the middle three seconds, averaged across three repetitions at each load level. Unit of measure: Newton-meters (Nm).

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

• Variable Error (VE)

  Muscle force sense will be assessed by the accuracy of force reproduction during force-matching tasks. Variable Error (VE) will be calculated as the standard deviation of errors across three repetitions at each load level. Unit of measure: Newton-meters (Nm).

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

• Coefficient of Variation (CV) of generated force

  Ratio of the standard deviation to the mean force during the middle three seconds of sustained contraction in each trial, calculated separately for trials with and without visual feedback. Unit of Measure: Percentage (%).

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

Secondary Outcomes (4)

• Surface EMG root mean square (RMS) amplitude of ankle muscles

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

• Surface EMG median frequency of peroneus longus mucle

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

• Maximal voluntary isometric contraction (MVIC)

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

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.

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.

Sponsors & Collaborators

• University of Ljubljana: lead

Study Sites (1)

Faculty of Health Sciences

Ljubljana, 1000, Slovenia

RECRUITING

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: September 10, 2025
• First Posted: November 26, 2025
• Study Start: May 15, 2025
• Primary Completion: April 14, 2026
• Study Completion: May 4, 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)