Does Resistance Training Protocol Change Micromorphology in Achilles Tendinopathy?

May 2, 2026 updated by: Stanislav Machač, Ph.D, University Hospital, Motol
This work is designed as a prospective cohort study, in which the effects of a protocol of 12-week resistance training loading the Achilles tendon in patients with Achilles tendinopathy (AT) will be monitored. It is estimated that at least 20 patients will participate. In addition, there will be a small control group of healthy participants which will not complete the same protocol, but will be monitored for natural changes in same objectives. Group of patients will be instructed to perform a training protocol.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The research within one participant will last a total of 26 weeks from the initial to the final examination and will include control measurements at 6 and 12 weeks from the beginning of therapy. Potential participants will be selected based on the recommendation of a specialist doctor and their suitability will be assessed according to the inclusion criteria. They will then be invited to an initial examination. This will include an objective examination by a physiotherapist, a subjective assessment by the patient and an ultrasonographic (USG) examination followed by a micromorphological analysis using special software. At the end of the initial examination, the participant will be informed about training protocol.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Czechia
      • Prague, Czechia
        • University Hospital Motol and 2nd Faculty of Medicine, Charles University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • the patient shows symptoms of Achilles tendinopathy (pain, swelling and dysfunction in the area of Achilles tendon), which at least partially limit his quality of life during normal or sporting activities,
  • the patient is in the age group of 18-60 years,
  • the patient has difficulties in only one lower limb; the second, asymptomatic limb will be considered the reference,
  • the patient is not aware of any mechanical damage to the tendon in symptomatic limb in the past (e.g. partial or complete rupture as a result of an injury),
  • the patient has not undergone any treatment aimed at AS in the last 3 months (surgery, corticoid application, plasma therapy, shock waves, physiotherapy, etc.), objective US examination of AS shows structural changes (expansion, neovascularization, focal hypoechoic areas, etc.).

Exclusion Criteria:

  • patient has been diagnosed with a rheumatic disease or a disease of the central nervous system
  • patient is aware of mechanical damage to the Achilles tendon as a result of an injury in the past.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Resistance training protocol
Participants in this group will complete a 12-week ankle dorsiflexion resistance training protocol according to Silbernagel. It is a series of heel rise exercises with a gradual progression of load according to defined criteria, which the patient practices every day.
Other: Achilles Tendon Loading Exercise Protocol According to Silbernagel
It is a 12-week Silbernagel ankle dorsiflexion resistance training protocol. It is a series of exercises with a gradual progression of load according to defined criteria, which the patient practices every day.
No Intervention: Participants with healthy tendons

Participants in this group are considered healthy based on subjective judgment followed by clinical and ultrasound examination of the Achilles tendon.

In this group, no specific treatment will be performed, only Achilles tendon will be monitored through time.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Peak Spatial Frequency Radius at the site of Pathology
Time Frame: Change of initial values at 26 weeks follow up after beginning of the therapy.
Measured by spatial frequency analysis software from ultrasound picture in mm-1. In a linear view with specific settings of ultrasound machine, the site of the largest pathology is selected, then the image is saved and uploaded to the software that evaluates the PSFR parameter.
Change of initial values at 26 weeks follow up after beginning of the therapy.
Change in Tendon Diameter at the Place of Maximum Tendon Width
Time Frame: Change of initial values at 26 weeks follow up after beginning of the therapy.
Measured by tools in ultrasound machine in mm2. In linear view is selected maximal width place, then the tendon diameter is measured using device tools.
Change of initial values at 26 weeks follow up after beginning of the therapy.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in VISA-A Questionnaire Score
Time Frame: Change of initial values at 39 weeks follow up after beginning of the therapy.
The VISA-A questionnaire is standardized questionnaire for patients with Achilles tendinopathy. The results are recorded in points (0-100 points). The higher score indicates patients better condition.
Change of initial values at 39 weeks follow up after beginning of the therapy.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Motol

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Stanislav Machac, PhD, University Hospital Motol and 2nd Faculty of Medicine, Charles University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2023

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2024

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 19, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 19, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 24, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 7, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • EK-402 /22b

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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