Effects of Electrical Muscle Stimulation on Myofascial Pain Syndrome

NCT07315776 | Completed DMC

• 2 other identifiers: EP 22 0814961-6056
• Study Type: interventional
• Target: 65
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to determine if Electrical Muscle Stimulation (EMS) combined with Active Stretching (AS) (EMS+AS) and EMS+AS combined with Trigger Point Pressure Release (TPR) (EMS+AS+TPR) are effective treatments for Myofascial Pain Syndrome (MPS) in working adults. The study will also assess the safety of the EMS+AS intervention. The main questions it aims to answer are: Do EMS+AS and EMS+AS+TPR lead to greater pain reduction, increased pressure pain threshold, and improved surface electromyography (sEMG) activity when compared to standard treatments? Furthermore, what is the participant feedback regarding EMS+AS and other treatments? Researchers will compare EMS+AS to passive stretching (PS) and TPR to see if EMS+AS and EMS+AS+TPR are effective in treating myofascial trigger points in the trapezius muscle. Participants will receive seven interventions across a single visit, including PS, EMS+AS, TPR, TPR combined with AS (TPR+AS), EMS+AS+TPR, Sham stimulation, and Transcutaneous Electrical Nerve Stimulation (TENS). Each treatment will consist of three 10-second sets with a 10-second rest between sets, and a 2-minute break provided between different treatments. Participants will have measurements taken on changes in pain intensity, pressure pain threshold, and sEMG activity during trapezius action pre- and post-treatment. Additionally, participants will report personal information, previous MPS treatments, and baseline health status, and provide feedback on satisfaction, treatment preferences, exercise knowledge for MPS prevention, and qualitative comments. For supplementary data, we selected only the EMS+AS and TPR interventions with the same protocol to evaluate changes in range of motion and changes in trigger point size and trapezius thickness (both at rest and during stretching) via ultrasound imaging.

Conditions

Myofascial Pain Syndrome (MPS)

Keywords

Electrical Muscle Stimulation; Myofascial pain syndrome; trigger point pressure release; electromyography; pain intensity; pressure pain threshold; ultrasound images

Outcome Measures

Primary Outcomes (4)

• Changes in Pain intensity

  Changes in pain intensity before and after treatment were measured using a numeric rating scale (0-10), where 0 represents no pain and 10 represents the worst possible pain. A reduced score indicates a better outcome.

  Baseline and Day 1 (immediately post-intervention)

• Changes in pressure pain threshold

  Changes in pressure pain threshold between before and after treatment were measured using a digital algometer (Wagner, Greenwich, USA). Pressure pain threshold was measured in kilogram force (kgf) or kilograms per square centimeter (kg/cm²). An increased score indicates a better outcome.

  Baseline and Day 1 (immediately post-intervention)

• Changes in median frequency of EMG activity

  Changes in the median frequency of surface electromyography (EMG) before and after treatment were recorded in hertz (Hz) using a 16-channel sEMG (Delsys Trigno Maize Sensor system). Changes in median frequency reflect physiological changes in muscle function. An increase in median frequency during trapezius muscle activity indicates physiological improvement.

  Baseline and Day 1 (immediately post-intervention)

• % maximum volunatary contraction (MVC) improvement

  %MVC improvement of EMG activity before and after treatment was recorded in percent (%) after calculating the root mean square normalized to pre-treatment values using a 16-channel sEMG (Delsys Trigno Maize Sensor system). An increase in %MVC during trapezius muscle activity indicates muscle function improvement.

  Baseline and Day 1 (immediately post-intervention)

Secondary Outcomes (4)

• Changes in range of motion (ROM) of neck deviation

  Baseline and Day 1 (immediately post-intervention)

• Changes in myofascial trigger point (MTP) size

  Baseline and Day 1 (immediately post-intervention)

• Changes in echointensiy at the myofascial trigger point (MTP)

  Baseline and Day 1 (immediately post-intervention)

• Changes in trapezius muscle thickness

  Baseline and Day 1 (immediately post-intervention)

Other Outcomes (1)

• Particpants' feedback

  Day 1 (Post-treatment assessment)

Study Arms (7)

Therapist-assisted Passive stretching (PS)

ACTIVE COMPARATOR

Passive Stretching with Therapist Assistance: The protocol consisted of three sets of stretching. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: Therapist-assisted Passive stretching (PS)

The two-combination of EMS+AS

EXPERIMENTAL

Electrical Muscle Stimulation (EMS) combined with Active Stretching (AS) was applied to the upper or middle trapezius muscle to facilitate muscle elongation. The protocol consisted of three sets of performing. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: The two-combination of EMS+AS

Trigger point pressure release (TPR)

ACTIVE COMPARATOR

Trigger Point Pressure Release (TPR): TPR was directly applied to the MTP of upper or middle trapezius muscle.The protocol consisted of three sets of performing. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: Trigger point pressure release (TPR)

Trigger point pressure release combined with active stretching (TPR+AS)

OTHER

Trigger Point Pressure Release (TPR) combined with Active Stretching (AS) was performed either by using neck deviation for the upper trapezius muscle or by using scapula protraction for the middle trapezius muscle during TPR. The protocol consisted of three sets of performing. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: Trigger point pressure release combined with active stretching (TPR+AS)

The triple combination therapy of EMS+AS+TPR

EXPERIMENTAL

This triple combination therapy was applied to enhance MTP release in the upper or middle trapezius muscles. The protocol consisted of three sets of performing. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: The triple combination therapy of EMS+AS+TPR

Transcutaneous electrical nerve stimulation (TENS)

ACTIVE COMPARATOR

Transcutaneous Electrical Nerve Stimulation (TENS) was applied on the upper or middle trapezius muscles without stretching. The protocol consisted of three sets of operating. Each set was performed for 10 seconds and followed by a 10-second break, totaling one minute for the single session.

Other: Transcutaneous electrical nerve stimulation (TENS)

Sham stimulation combined with active stretching (SS+AS)

SHAM COMPARATOR

SS+AS consisted only of active stretching of the upper or middle trapezius muscle, with no electrical current applied from EMS device. Self-stretching was performed for three sets, with each 10-second stretch followed by a 10-second break, resulting in a total session time of one minute.

Other: Sham stimulation combined with active stretching (SS+AS)

Interventions

Therapist-assisted Passive stretching (PS) OTHER

The therapist stretched the upper trapezius muscle via shoulder depression and neck deviation. The middle trapezius muscle was stretched using scapular protraction while simultaneously stabilizing the mid-spine and gently pulling the arm inward.

Also known as: PS

Therapist-assisted Passive stretching (PS)

The two-combination of EMS+AS OTHER

Electrical Muscle Stimulation combined with Active Stretching: The EMS component utilized parameters of 20 Hz frequency and 100 µs pulse width, with the amplitude adjusted individually for intensity. The EMS electrodes were placed across the muscle fibers with a 1 cm inter-electrode distance. This placement was specifically designed to restrict the electrical field, thereby inducing a local muscle contraction that opposes the direction of the active stretch being performed concurrently.

Also known as: EMS+AS

The two-combination of EMS+AS

Trigger point pressure release (TPR) OTHER

Trigger point Pressure Release (TPR): The therapist utilized a PAIN TEST™ FPX series pressure gauge (Wagner Instruments). A round rubber 1 cm2 force gauge probe was applied directly on the MTP by gradually increasing the pressure until the participant reached their maximum pressure tolerance level.

Also known as: TPR

Trigger point pressure release (TPR)

Trigger point pressure release combined with active stretching (TPR+AS) OTHER

Trigger point Pressure Release combined with Active Stretching (TPR+AS) was performed by applying active stretching of the trapezius muscle concurrently with TPR, using the same protocol as the standalone TPR intervention.

Also known as: TPR+AS

Trigger point pressure release combined with active stretching (TPR+AS)

The triple combination therapy of EMS+AS+TPR OTHER

Electrical Muscle Stimulation combined with Active Stretching during Trigger point Pressure Release (EMS+AS+TPR): This triple combination therapy utilized the EMS+AS component protocol concurrently with the TPR intervention, applying the identical protocols established for the standalone EMS+AS and TPR procedures.

Also known as: EMS+AS+TPR

The triple combination therapy of EMS+AS+TPR

Transcutaneous electrical nerve stimulation (TENS) OTHER

Transcutaneous Electrical Nerve Stimulation (TENS) was applied using the conventional protocol (60 Hz,100 µs,5 mA) with two electrodes placed directly over the MTP region, without stretching.

Also known as: TENS

Transcutaneous electrical nerve stimulation (TENS)

Sham stimulation combined with active stretching (SS+AS) OTHER

Sham stimulation combined with active stretching (SS+AS): Participants performed AS using the same EMS device and electrode placement as in the EMS+AS protocol. However, no electrical current was applied. The procedure began with a conversation about the treatment from the researcher while the current amplitude was reduced from 1 mA to 0 mA during the trapezius muscle stretching, accompanied by a beeping sound to simulate stimulation. Participants were subsequently informed that this was the intended treatment.

Also known as: SS+AS

Sham stimulation combined with active stretching (SS+AS)

Eligibility Criteria

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

You may qualify if:

• Participants over 18 years old with either active or latent myofascial trigger points in the trapezius muscle were diagnosed with MPS by a General Practitioner (GP).
• Participants have no history of chronic diseases (cancer, cervical nerve root compression, heart arrhythmias, including hyperthyroid, muscle weakness, seizure, skin infection at the upper back, spinal cord injury, stroke).
• Participants have ability to move the upper limbs.
• Participants reported no use of pacemakers or strong pain relievers, no allergies to metals, gels, or cleaning products, and no pre-existing severe muscle soreness.

You may not qualify if:

• Participants less 18 years old with no myofascial trigger points in the trapezius muscle.
• Participants to have history of chronic diseases (cancer, cervical nerve root compression, heart arrhythmias, including hyperthyroid, muscle weakness, seizure, skin infection at the upper back, spinal cord injury, stroke).
• Participants cannot move the upper limbs.
• Participants reported use of pacemakers or strong pain relievers, and allergies to metals, gels, or cleaning products, and pre-existing severe muscle soreness.

Sponsors & Collaborators

• University of Bath: lead
• Suranaree University of Technology: collaborator

Study Sites (1)

Department of Electronic and Electrical Engineering

Bath, BA2 7AY, United Kingdom

Location

Related Links

• Main Study Protocol
• Main Study Ethics Amendment
• Ultrasound Study Protocol
• Ultrasound Study Ethics Letter (Supplementary Data)

MeSH Terms

Conditions

Myofascial Pain Syndromes; Pain

Interventions

Muscle Stretching Exercises; Transcutaneous Electric Nerve Stimulation

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Exercise Therapy; Rehabilitation; Aftercare; Continuity of Patient Care; Patient Care; Therapeutics; Physical Therapy Modalities; Exercise; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Electric Stimulation Therapy; Analgesia; Anesthesia and Analgesia

Study Officials

• SEEKAOW CHURPROONG, MD.

  University of Bath, United Kingdom.

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Masking Details: Treatments were administered in a computer-generated randomised order, concealed from participants.The principal researcher collected all anonymous data for blinded analysis.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: November 27, 2025
• First Posted: January 2, 2026
• Study Start: November 25, 2022
• Primary Completion: March 28, 2024
• Study Completion: September 20, 2025
• Last Updated: January 2, 2026

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)