Impact of Different Electrical Frequencies Used in Percutaneous Neuromodulation on Muscle Strength and Pressure Pain Thresholds

NCT07269925 | Not Yet Recruiting

• 1 other identifier: UComplutenseMadrid-PENS
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Shoulder Pain

Keywords

Percutaneous electrical nerve stimulation; Strength; Pain pressure thresholds

Outcome Measures

Primary Outcomes (2)

• Muscle strength

  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

  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 Outcomes (4)

• Pain Pressure Thresholds - Latent MTrP

  Baseline

• Pain Pressure Thresholds - Latent MTrP

  Post-intervention (10 minutes)

• Pain Pressure Thresholds - Tibialis anterior

  Baseline

• Pain Pressure Thresholds - Tibialis anterior

  Post-intervention (10 minutes)

Study Arms (2)

Low Frequency PENS

EXPERIMENTAL

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

High Frequency PENS

EXPERIMENTAL

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

Interventions

Percutaneous electrical nerve stimulation: Low frequency OTHER

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.

Low Frequency PENS

Percutaneous electrical nerve stimulation: High frequency OTHER

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

High Frequency PENS

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Universidad Complutense de Madrid: lead
• Universidad Rey Juan Carlos: collaborator

Study Sites (1)

ATMIS

Krakow, Poland, Poland

Location

MeSH Terms

Conditions

Shoulder Pain

Condition Hierarchy (Ancestors)

Arthralgia; Joint Diseases; Musculoskeletal Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Juan Antonio Valera-Calero, PhD

CONTACT

0034 653 766 841; juavaler@ucm.es

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Randomized, Double-Blinded, Placebo-Controlled Trial

Study Record Dates

• First Submitted: November 25, 2025
• First Posted: December 8, 2025
• Study Start: February 15, 2026
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): July 30, 2026
• Last Updated: December 15, 2025

Record last verified: 2025-12

Locations

PL (1)