GOAT (Gait Observation of Achilles Tendon) (GOAT)

May 22, 2026 updated by: Nantes University Hospital

Characterization of Mechanical Properties of Achilles Tendon During Gait in Spastic Paresis Syndrome

The purpose of this study is to evaluate the mechanical properties of the Achilles tendon (stiffness, length, volume) and the force production capacities of the gastrocnemius medialis muscle in patients with spastic paresis (post-stroke or incomplete spinal cord injury) compared to healthy subjects, during gait.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Spastic paresis alters the physiological muscle-tendon interaction during gait. Previous observations suggest that specific gait deviations, such as equinus and non-equinus patterns, are primarily driven by adaptations in the Achilles tendon behavior rather than the muscle belly structure. This observational, prospective study aims to characterize the determinants of these gait patterns by specifically investigating the mechanical properties of the Achilles tendon (stiffness, length, volume) relative to the force production capacities of the gastrocnemius medialis (GM) muscle (voluntary activation, volume).

A total of 60 participants will be recruited: 20 patients with post-stroke hemiparesis, 20 patients with incomplete spinal cord injury, and 20 age-, gender-, and morphologically matched healthy controls. Neurological participants will be stratified into "equinus" or "non-equinus" cohorts based on their ankle kinematics during the terminal stance phase of gait.

The study protocol consists of a single evaluation session per participant, comprising three main assessments:

Force and Tendon Mechanics Evaluation: Conducted on an isokinetic dynamometer. Passive mobilization and isometric plantar flexion contractions (submaximal and maximal) will be performed. The twitch interpolation technique, using superimposed electrical stimulation of the tibial nerve, will be applied to assess the voluntary activation level of the GM. Concurrently, an ultrasound probe placed on the GM myotendinous junction will track tissue displacement to calculate Achilles tendon stiffness.

Synchronized 3D Gait Analysis: Participants will perform several walking trials in a motion analysis laboratory. Three-dimensional kinematics (reflective markers), muscle activity (surface electromyography on lower limb muscles), and real-time muscle-tendon behavior (ultrasound imaging of the calf) will be recorded synchronously to evaluate the in vivo behavior of the muscle-tendon unit.

3D Ultrasound Acquisition: A free-hand 3D ultrasound sweep of the GM muscle and Achilles tendon will be performed with the participant in a prone position to reconstruct and measure tissue volumes and lengths.

The primary outcome is the Young's modulus of the Achilles tendon. Secondary outcomes include structural parameters (length and volume) and maximal voluntary activation. Statistical analyses will compare these parameters across the equinus, non-equinus, and healthy control groups.

Study Type

Observational

Enrollment (Estimated)

60

Contacts and Locations

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

Study Contact

Study Contact Backup

Study Locations

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

A maximum of 60 subjects will be included. Twenty will be post-stroke patients with hemiparesis, 20 will be post-incomplete spinal cord injury patients, and 20 will be healthy subjects.

Description

Inclusion Criteria:

Study population:

• Cognitive abilities compatible with the experiment: no language or judgement disorders preventing understanding of the research or expression of consent. An aphasia severity score greater than or equal to 3 on the Boston Diagnostic Aphasia Examination (BDAE) scale will be required for inclusion.

Post-stroke population:

  • Adult male or female
  • Patient who has had a stroke > 7 days ago
  • Patient hospitalised (in conventional hospitalisation or day hospital) in the neurological physical and medical rehabilitation department of Nantes University Hospital
  • Patients with voluntary motor function rated between 2 and 4 on the MRC (Medical Research Council) scale at the GM level
  • Patients classified as 3 to 8 on the New Functional Ambulation Classification
  • Indication to perform a quantified gait analysis as part of clinical management

Post-spinal cord injury population:

  • Adult men or women
  • Patients with incomplete spinal cord injury graded ASIA AIS C or D from C2 to L5
  • Patients hospitalised (in conventional hospitalisation or day hospital) in the neurological physical and occupational therapy department of Nantes University Hospital
  • Patients with voluntary motor function rated between 2 and 4 on the MRC (Medical Research Council) scale at GM level
  • Patients rated 13-20 on the WISCI-II scale
  • Indication for a quantified gait analysis as part of clinical care

Healthy population:

• Adult men or women with no nervous system disorders.

Exclusion Criteria:

Post-stroke and post-spinal cord injury population:

  • Minors;
  • History of calf surgery, surgery to reduce triceps surae spasticity, or intramuscular injection (e.g. botulinum toxin) in the plantar flexors < 6 months;
  • Patients with a progressive condition that contraindicates exertion (syrinx, cardiovascular instability);
  • Peripheral pathology of the lower limb in question.

Healthy population:

  • History of calf surgery;
  • History of muscle injury, fracture or sprain of the lower limb < 3 months;
  • History of neurological condition.

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Equinus pattern
Patients with stroke or incomplete spinal cord injury exhibiting an equinus gait pattern (excessive plantar flexion in terminal stance).
Diagnostic test: 3D Gait Analysis
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Ultrasound
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Dynamometry
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Non-equinus pattern
Patients with stroke or incomplete spinal cord injury exhibiting a non-equinus gait.
Diagnostic test: 3D Gait Analysis
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Ultrasound
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Dynamometry
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Healthy controls
Age, gender, height, and weight-matched individuals without neurological pathology.
Diagnostic test: 3D Gait Analysis
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Ultrasound
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.
Diagnostic test: Dynamometry
Evaluation includes maximal and sub-maximal isometric plantar flexion on a dynamometer with electrical stimulation, 3D quantified gait analysis synchronized with surface electromyography and ultrasound, and 3D ultrasound volume acquisition.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Achilles Tendon Young's Modulus
Time Frame: Day 1 (Baseline)
Young's modulus of the Achilles tendon (in kPa) measured at 3% tendon strain using ultrasound and dynamometry.
Day 1 (Baseline)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Achilles Tendon and Gastrocnemius Medialis Length and Volume
Time Frame: Day 1 (Baseline)
Length and volume reconstructed via 3D ultrasound using 3DSlicer software.
Day 1 (Baseline)
Gastrocnemius Medialis Voluntary Activation
Time Frame: Day 1 (Baseline)
Maximal voluntary activation measured using the twitch interpolation technique.
Day 1 (Baseline)

Collaborators and Investigators

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

Sponsor

Nantes University Hospital

Collaborators

Laboratoire Motricité, Interactions, Performance (MIP)

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

March 9, 2026

First Submitted That Met QC Criteria

March 9, 2026

First Posted (Actual)

March 12, 2026

Study Record Updates

Last Update Posted (Actual)

May 27, 2026

Last Update Submitted That Met QC Criteria

May 22, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RC26_0051
  • 2026-A00526-45 (Other Identifier: ANSM)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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