NCT07453485

Brief Summary

The Achilles tendon exhibits high tensile strength and can withstand extremely high loads. However, it is susceptible to injuries such as tendinopathies and ruptures, which are associated with structural alterations and loss of function. Strategies have been investigated to enhance clinical rehabilitation. Nevertheless, the effects of neuromuscular electrical stimulation on pain and functional improvement, as well as the optimal dosing parameters for the rehabilitation of Achilles tendon injuries, remain inconclusive. The aim of this study is to compare the immediate effects of two electrical stimulation protocols on pain, functional performance, peripheral oxygen extraction, and maximal tendon displacement during a single leg heel rise functional task in patients with Achilles tendinopathy and/or a history of Achilles tendon rupture. In addition, this study aims to characterize Achilles tendon structural properties and ankle plantarflexor muscle strength in this population.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
30

participants targeted

Target at below P25 for not_applicable

Timeline
43mo left

Started Jan 2026

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress11%
Jan 2026Dec 2029

Study Start

First participant enrolled

January 6, 2026

Completed
1 month until next milestone

First Submitted

Initial submission to the registry

February 13, 2026

Completed
21 days until next milestone

First Posted

Study publicly available on registry

March 6, 2026

Completed
3.5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

August 30, 2029

Expected
4 months until next milestone

Study Completion

Last participant's last visit for all outcomes

December 30, 2029

Last Updated

March 6, 2026

Status Verified

March 1, 2026

Enrollment Period

3.6 years

First QC Date

February 13, 2026

Last Update Submit

March 2, 2026

Conditions

Achilles Tendinopathy (AT)Achilles Tendon Rupture

Keywords

Achilles tendonAchilles tendinopathyAchilles tendon ruptureNeuromuscular electrical stimulationPainFunctional performance

Outcome Measures

Primary Outcomes (1)

  • Pain level

    Pain intensity during the single leg heel rise task will be assessed using the Visual Analog Scale, consisting of a numerical scale ranging from 0 to 10 points, in which 0 represents no pain and 10 corresponds to the worst pain ever experienced by the participant.

    Immediately after the performance of the functional task

Secondary Outcomes (15)

  • Total time

    Immediately after the performance of the functional task.

  • Maximal displacement

    Immediately after the performance of the functional task.

  • Total work

    Immediately after the performance of the functional task.

  • Total power

    Immediately after the performance of the functional task.

  • Number of repetitions

    Immediately after the performance of the functional task.

  • +10 more secondary outcomes

Study Arms (4)

Control without active intervention

NO INTERVENTION

In this group, participants will perform three sets of 10 repetitions of the single leg heel rise functional task without the application of electrical stimulation. Immediately after each set, pain level, functional performance, peripheral oxygen extraction, and maximal Achilles tendon displacement will be assessed.

Electrical stimulation applied at the maximum tolerated intensity

EXPERIMENTAL

Under this condition, participants will perform three sets of 10 repetitions of the single leg heel rise functional task with superimposed electrical stimulation applied at the maximum tolerated intensity, characterized by visible muscle contraction and associated with a self-reported discomfort level between 8 and 10 on the Numeric Rating Scale. Immediately after each set, pain level, functional performance, peripheral oxygen extraction, and maximal Achilles tendon displacement will be assessed.

Device: Neuromuscular Electrical Stimulation (NMES)

Control with sham stimulation

PLACEBO COMPARATOR

For this condition, participants will perform three sets of 10 repetitions of the single leg heel rise functional task with superimposed sham electrical stimulation. Electrical stimulation parameters will initially be configured identically to those used in the active intervention. However, to ensure adequate blinding, stimulation will be applied for approximately 40 seconds and then gradually reduced until complete cessation. From this point onward, no additional current will be delivered, although the device will remain on and the electrodes will remain in place throughout the test. Immediately after each set, pain level, functional performance, peripheral oxygen extraction, and maximal Achilles tendon displacement will be assessed.

Device: Neuromuscular Electrical Stimulation (NMES)

Sensory-level electrical stimulation

ACTIVE COMPARATOR

In this condition, participants will perform three sets of 10 repetitions of the single leg heel rise functional task with superimposed electrical stimulation applied at the sensory level, defined as the highest intensity that does not elicit visible muscle contraction. Immediately after each set, pain level, functional performance, peripheral oxygen extraction, and maximal Achilles tendon displacement will be assessed.

Device: Neuromuscular Electrical Stimulation (NMES)

Interventions

Neuromuscular Electrical Stimulation (NMES)DEVICE

Neuromuscular electrical stimulation-induced contractions will be delivered using an electrical stimulator connected to a pair of 5×5 cm self-adhesive surface electrodes. Stimulation will be applied in a superimposed manner during voluntary movement, at a frequency of 75 Hz and a phase duration of 400 µs.

Control with sham stimulationElectrical stimulation applied at the maximum tolerated intensitySensory-level electrical stimulation

Eligibility Criteria

Age18 Years - 60 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64)

You may qualify if:

  • Primary complaint of pain localized in the midportion (2-6 cm proximal to the calcaneus) or insertion of the Achilles tendon, and/or a history of Achilles tendon rupture occurring at least 3 months prior to assessment.
  • Pain on palpation of the Achilles tendon.
  • Pain during load-bearing activities

You may not qualify if:

  • Exclusive diagnosis of bursitis confirmed by ultrasonographic assessment
  • Any other lower limb injury
  • History of lower limb surgery within the past year
  • Previous Achilles tendon tenoplasty performed less than 3 months prior to assessment

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

University of Brasilia

Brasília, Federal District, 72220900, Brazil

RECRUITING

MeSH Terms

Conditions

Pain

Condition Hierarchy (Ancestors)

Neurologic ManifestationsSigns and SymptomsPathological Conditions, Signs and Symptoms

Central Study Contacts

João LQ Durigan, PhD

CONTACT

+55 61 3107-8450joaodurigan@gmail.com

José RS Júnior, PhD

CONTACT

+55 61 3107-8450joserobertofisio@gmail.com

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
SINGLE
Who Masked
PARTICIPANT
Purpose
TREATMENT
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

February 13, 2026

First Posted

March 6, 2026

Study Start

January 6, 2026

Primary Completion (Estimated)

August 30, 2029

Study Completion (Estimated)

December 30, 2029

Last Updated

March 6, 2026

Record last verified: 2026-03

Data Sharing

IPD Sharing
Will not share

Locations

BR(1)