Effects of Electrical Muscle Stimulation on Myofascial Pain Syndrome

University of Bath65 enrolled

Overview

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.

The main study measures included changes in pain intensity, pressure pain threshold, and sEMG activity. The supplementary study measures included ultrasound images and range of motion.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

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.

The two-combination of EMS+ASOTHER

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.

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.

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.

The triple combination therapy of EMS+AS+TPROTHER

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.

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.

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.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 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. Exclusion Criteria: * 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.

Outcomes

Primary Outcomes

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.