Shoulder PainPENS-DOSENCT07269925
Impact of Different Electrical Frequencies Used in Percutaneous Neuromodulation on Muscle Strength and Pressure Pain Thresholds
A study testing Percutaneous electrical nerve stimulation: High frequency and Percutaneous electrical nerve stimulation: Low frequency in people with Shoulder Pain, run by Universidad Complutense de Madrid at 2 sites in Poland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Shoulder Pain
- What is being tested?
- Percutaneous electrical nerve stimulation: High frequency and Percutaneous electrical nerve stimulation: Low frequency
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 2 sitesPoland
- Study dates
- 15 Feb 2026to 30 Jul 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Poland2 sites, 2 recruiting
- Not yet recruiting
ATMIS
Krakow, Poland
Juan Antonio Valera-Calero, 0034 653 766 841, juavaler@ucm.es
- Recruiting
ATMIS
Nowy Targ, 34-400
Mateusz Kobylarz, Physiotherapist, +48881755481, md.kobylarz@alumnos.urjc.es
About this study
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
- Being tested
- Percutaneous electrical nerve stimulation: High frequency, Percutaneous electrical nerve stimulation: Low frequency
- Keywords
- Percutaneous electrical nerve stimulation, Strength, Pain pressure thresholds
- Medical subject headings
- Shoulder Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Percutaneous electrical nerve stimulation: High frequencyOther
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
Percutaneous electrical nerve stimulation: Low frequencyOther
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Other: Percutaneous electrical nerve stimulation: High frequency |
What is being measured
The primary outcome is the main question the study is designed to answer.
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°.
Measured: 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°.
Measured: Post-intervention (10 minutes)
Secondary outcomes (4)
Pain Pressure Thresholds - Latent MTrP
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.
Measured: Baseline
Pain Pressure Thresholds - Latent MTrP
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.
Measured: Post-intervention (10 minutes)
Pain Pressure Thresholds - Tibialis anterior
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.
Measured: Baseline
Pain Pressure Thresholds - Tibialis anterior
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.
Measured: Post-intervention (10 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Dec 2025
- Study start15 Feb 2026
- Primary completion30 Jun 2026 (estimated)
- Study completion30 Jul 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Shoulder PainStudies of the same condition, open and under way.
- More trials run by Universidad Complutense de MadridThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, Double-Blinded, Placebo-Controlled Trial
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidad Complutense de Madrid
- Sponsor type
- University, hospital or other
- Collaborators
- Universidad Rey Juan Carlos
- Responsible party
- Principal investigator, JUAN ANTONIO VALERA CALERO, Universidad Complutense de Madrid
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07269925
- Sponsor's protocol ID
- UComplutenseMadrid-PENS
- Acronym
- PENS-DOSE
- Status last verified
- May 2026
- First submitted
- 25 Nov 2025
- Last updated
- 8 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Different Electrical Frequencies Used in Percutaneous Neuromodulation on Muscle Strength and Pressure Pain Thresholds
- ClinicalTrials.gov ID
- NCT07269925
- Acronym / sponsor ID
- PENS-DOSE / UComplutenseMadrid-PENS
- Conditions
- Shoulder Pain
- Keywords
- Percutaneous electrical nerve stimulation, Strength, Pain pressure thresholds
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Universidad Complutense de MadridUniversity, hospital or other
- Collaborators
- Universidad Rey Juan Carlos
- Study start
- 15 Feb 2026 (actual)
- Primary completion
- 30 Jun 2026 (estimated)
- Study completion
- 30 Jul 2026 (estimated)
- First posted
- 8 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, Double-Blinded, Placebo-Controlled Trial
| Arm | Type | Receives |
|---|---|---|
| Low Frequency PENS | Experimental | Other: Percutaneous electrical nerve stimulation: Low frequencyParticipants 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. |
| High Frequency PENS | Experimental | Other: Percutaneous electrical nerve stimulation: High frequencyParticipants 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. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- 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.
Key exclusion criteria (7 listed)
- 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).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Percutaneous electrical nerve stimulation: High frequencyA 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 | Other | High Frequency PENS |
| Percutaneous electrical nerve stimulation: Low frequencyA 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. | Other | Low Frequency PENS |
Primary outcome
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°.
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°.
4 secondary outcomes
Pain Pressure Thresholds - Latent MTrP
Time frame: Baseline
Pain Pressure Thresholds - Latent MTrP
Time frame: Post-intervention (10 minutes)
Pain Pressure Thresholds - Tibialis anterior
Time frame: Baseline
Pain Pressure Thresholds - Tibialis anterior
Time frame: Post-intervention (10 minutes)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Percutaneous electrical nerve stimulation: High frequency and Percutaneous electrical nerve stimulation: Low frequency in people with Shoulder Pain, run by Universidad Complutense de Madrid at 2 sites in Poland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Poland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Juan Antonio Valera-Calero, PhD (0034 653 766 841, juavaler@ucm.es), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Muscle strength (time frame: Baseline). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 May 2026.