Impact of Different Electrical Frequencies Used in Percutaneous Neuromodulation on Muscle Strength and Pressure Pain Thresholds (PENS-DOSE)

May 5, 2026 updated by: JUAN ANTONIO VALERA CALERO, Universidad Complutense de Madrid

Percutaneous electrical nerve stimulation (PENS) involves delivering electrical currents through fine filiform needles inserted near tissues such as muscles, ligaments, or nerves. It has been explored for various chronic pain conditions affecting the cervical and lumbar spine, as well as the upper and lower limbs. Despite its growing clinical use, the overall quality of evidence supporting PENS for chronic musculoskeletal pain remains limited. Most studies have applied the technique directly over nerve structures, and while some reviews have shown greater pain reduction compared to transcutaneous electrical nerve stimulation (TENS), the superiority of PENS has not been conclusively demonstrated. Research specifically examining its application on nerve tissues, particularly in the upper limbs, remains scarce. Some preliminary and single-case studies have reported improvements in pain and disability following PENS directed at the radial nerve, but these findings are limited by small sample sizes and the absence of control groups. The physiological mechanisms underlying PENS are still not fully understood, though both peripheral and central processes are believed to be involved. Evidence suggests that PENS can reduce local sensitivity to pressure pain through peripheral mechanisms and may also enhance descending inhibitory control by activating conditioned pain modulation at the central level. However, further studies are necessary to clarify these effects.

Since to date, limited research has specifically examined the optimal PENS dosage, the present study aimed to compare two PENS dosage for improving muscle strength and pain pressure thresholds.

Study Overview

Status

Status

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

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.

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

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Juan Antonio Valera-Calero, PhD
  • Phone Number: 0034 653 766 841
  • Email: juavaler@ucm.es

Study Locations

  • Poland
      • Nowy Targ, Poland, 34-400
    • Poland
      • Krakow, Poland, Poland
        • Not yet recruiting
        • ATMIS
        • Contact:
          • Juan Antonio Valera-Calero
          • Phone Number: 0034 653 766 841
          • Email: juavaler@ucm.es

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
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Presence of at least one latent myofascial trigger point (MTrP) in the infraspinatus muscle, identified according to the most recent Delphi consensus criteria.
  • Ability to read, understand, and sign the written informed consent form.

Exclusion Criteria:

  • Current pharmacological treatment that may affect muscle tone.
  • History of shoulder or spinal surgery.
  • Traumatic disorders such as whiplash-associated injuries, dislocations, or fractures.
  • Neuropathies, including radiculopathies or myelopathies.
  • Severe medical conditions (e.g., tumors, fractures, neurological or systemic diseases).
  • Clinically relevant asymmetries.
  • Generalized musculoskeletal conditions such as fibromyalgia.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

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: Low Frequency PENS
Participants will receive a single session of PENS setting 2 Hz frequency, 250 µs pulse width, 10 minutes duration, with an intensity (mA) sufficient to elicit a visible motor response while remaining comfortable for the patient.
Other: Percutaneous electrical nerve stimulation: Low frequency
A single PENS session will be applied under ultrasound guidance using sterile, single-use filiform needles placed in the suprascapular and axillary nerves and connected to an electrostimulator APSe4 (Agupunt, Barcelona). Dosage will be: 2 Hz frequency, 250 µs pulse width, 10 minutes duration, with an intensity (mA) sufficient to elicit a visible motor response while remaining comfortable for the patient.
Experimental: High Frequency PENS
Participants will receive a single session of PENS setting 100 Hz frequency, 250 µs pulse width, 5-second stimulation followed by 55-second rest, with an intensity (mA) sufficient to elicit a visible motor response while remaining comfortable for the patient and repeated five times.
Other: Percutaneous electrical nerve stimulation: High frequency

A single PENS session will be applied under ultrasound guidance using sterile, single-use filiform needles placed in the suprascapular and axillary nerves and connected to an electrostimulator APSe4 (Agupunt, Barcelona).

Dosage will be: 100 Hz frequency, 250 µs pulse width, 5-second stimulation followed by 55-second rest, repeated five times

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
Muscle strength
Time Frame: Baseline
Shoulder external rotator strength will be assessed using a handheld dynamometer (TruStrength, Hawkin Dynamics, USA), previously validated for measuring isometric muscle contraction strength. Participants will perform a standardized isometric external rotation test in a seated position with the elbow flexed at 90°.
Baseline
Muscle strength
Time Frame: Post-intervention (10 minutes)
Shoulder external rotator strength will be assessed using a handheld dynamometer (TruStrength, Hawkin Dynamics, USA), previously validated for measuring isometric muscle contraction strength. Participants will perform a standardized isometric external rotation test in a seated position with the elbow flexed at 90°.
Post-intervention (10 minutes)

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
Pain Pressure Thresholds - Latent MTrP
Time Frame: Baseline
The assessment of pressure pain thresholds (PPT) at the myofascial trigger point (MTrP) will be evaluated three times at each measurement site using a analog algometer, applying a pressure rate of approximately 5 N/s.
Baseline
Pain Pressure Thresholds - Latent MTrP
Time Frame: Post-intervention (10 minutes)
The assessment of pressure pain thresholds (PPT) at the myofascial trigger point (MTrP) will be evaluated three times at each measurement site using a analog algometer, applying a pressure rate of approximately 5 N/s.
Post-intervention (10 minutes)
Pain Pressure Thresholds - Tibialis anterior
Time Frame: Baseline
The assessment of pressure pain thresholds (PPT) at a distal location (Tibia's anterior) will be evaluated three times at each measurement site using a analog algometer, applying a pressure rate of approximately 5 N/s.
Baseline
Pain Pressure Thresholds - Tibialis anterior
Time Frame: Post-intervention (10 minutes)
The assessment of pressure pain thresholds (PPT) at a distal location (Tibia's anterior) will be evaluated three times at each measurement site using a analog algometer, applying a pressure rate of approximately 5 N/s.
Post-intervention (10 minutes)

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.
Universidad Complutense de Madrid

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Universidad Rey Juan Carlos

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.
February 15, 2026

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.
June 30, 2026

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.
July 30, 2026

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).
November 25, 2025

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.
November 25, 2025

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.
December 8, 2025

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 8, 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 5, 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.
  • UComplutenseMadrid-PENS

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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