Electrical stimulator for pain


Electrical Stimulation for Pain Management

Transcutaneous electrical nerve stimulation, or TENS, is a pain management technique that uses electricity to help alleviate pain. TENS has been a commonly used pain management therapy almost since it was first developed in the late 1960s. But like some other therapies, TENS results aren’t guaranteed — some people find TENS more helpful than others.

TENS treatment involves placing small electrodes, devices that conduct electricity, on the skin over the part of the body that’s in pain; they are held in place with adhesive. The electrodes are then attached to a machine that releases small waves of electricity, sending tiny electrical impulses through the electrodes to the painful joint or area of the body.

TENS for Pain Management: How It Works

How does electricity alleviate pain? It’s thought that the electrical impulses interrupt messages about pain sent from the nerves to the brain. The electricity blocks the activity of the pain receptors, which send those pain messages. If the brain doesn’t get the messages from the nerves, it doesn’t know that there’s pain, and you don’t feel any.

Another theory behind transcutaneous electrical nerve stimulation is that the electrical impulses released during TENS encourage the body to produce more of its own endorphins, which are natural pain relievers.

The electrical currents emitted by TENS are very low — don’t be worried that you’ll feel a big shock. However, it is common to feel a little warmth or even a tingling sensation at the site of the electrodes. One session takes up to 15 minutes, and may be repeated frequently to help alleviate pain.

TENS for Pain Management: Numerous Applications

TENS has been tried in a number of conditions as a pain management tool. TENS may be used to ease pain from:

  • Migraines and tension headaches
  • Cancer pain
  • Arthritis
  • Bursitis
  • Tendonitis
  • Chronically painful injuries
  • Pain after surgery
  • Pain during childbirth

You can receive TENS from your doctor, a physical therapist, or other health care professional. There are also U.S. Food and Drug Administration-approved TENS devices to use at home — you’ll need a prescription from your doctor to purchase one.

TENS for Pain Management: Effectiveness

TENS is often considered a form of complementary and alternative medicine. There have been a number of studies done on the effectiveness of TENS on pain management, most with conflicting results pointing to the need for more research. Small, separate studies found that TENS could be helpful in managing rheumatoid arthritis in the hand and pain from knee osteoarthritis. However, research that evaluated a wide spectrum of treatments for lower back pain rated TENS as poor.

One fact is certain: TENS does not cure the source of the pain or treat the underlying problem. Still, many people have found that TENS does relieve their short-term pain and find its use worthwhile, even if the pain does come back.

What does that mean for you and your pain management? Although the jury is still out on whether TENS is truly effective as a pain management therapy and for what types of pain, since some people do experience some pain relief from TENS, it’s worth talking to your doctor about the risks and benefits of trying it to manage your pain.

Versión en Español

How does TENS work?

A transcutaneous electrical nerve stimulator (TENS) sends electrical pulses through the skin to start your body’s own pain killers. The electrical pulses can release endorphins and other substances to stop pain signals in the brain.

TENS can reduce pain. It works best when used during activities such as walking, doing chores, or exercise. The video below shows how TENS can reduce pain and demontrates how to use a TENS unit.

TENS instructions

Your health care provider may have sent you home with these instructions. Print them for use during your exercise session.

What is TENS used for?

A TENS may be used to help with many types of chronic (long-term) pain, such as:

  • Arthritis or other joint pain
  • Back and neck pain
  • Fibromyalgia
  • Muscle pain
  • Neuropathic pain

When is it best to use TENS?

Research has shown that TENS is most helpful for chronic pain when used for at least 30 minutes while you are active. It is less effective when you are sitting still, lying down, or resting.

Do not use TENS if you have:

  • A cardiac pacemaker or defibrillator
  • Spinal cord stimulator
  • In-dwelling pumps or monitors
  • Any implanted metallic or electronic device

Talk with your health care provider if you have:

  • Cancer
  • Diabetes
  • Cognitive impairment
  • Epilepsy
  • Or are pregnant

People who are allergic to nickel and/or adhesives may have skin irritation with TENS.

For providers

Please consult our listing of evidence-based contraindications for TENS use.

TENS safety

Do not use TENS on:

  • Open wounds or rashes
  • Swollen, red, infected, or inflamed skin
  • Cancerous lesions, or close to them
  • Skin that does not have normal sensation (feeling)
  • Any part of your head or face
  • Any part of your throat
  • Both sides of the chest or trunk at the same time
  • Directly on your backbone

Do not use TENS while:

  • Bathing or showering
  • Sleeping
  • Driving
  • Using machinery

For your protection

  • Turn the TENS unit off before you put on, move, or take off the electrode patches.
  • Do not share your patches with other people.
  • Only use the TENS unit on yourself as instructed.
  • Keep out of the reach of children.
  • Electronic equipment, such as EKG monitors and EKG alarms, may not work the right way when TENS is in use.

Stop using TENS and talk with your doctor or health care team if you have:

  • Skin irritation (redness, rash, itching)
  • Headache
  • Dizziness
  • Nausea (feel like you are going to throw up)

How to use the TENS unit

Your TENS works by delivering an electrical current through wires and patches.

Your package should have:

  • TENS unit (dual channel)
  • Two wires with a total of 4 connectors
  • Four electrode patches
  • Power source/batteries
  • Belt clip

To start treatment

Make sure the skin around your painful area is clean (clean off oil/lotion) and dry. It is very important to put the patches on clean, dry skin so they make firm contact. If the patch is not secure, changes in the stimulation may happen, which could cause discomfort.

  1. Make sure the TENS unit is off.
  2. Put in the batteries, or charge the unit, using the instructions.
  3. Take the patches out of their plastic storage bag. Save the bag for future storage.
  4. Put the lead wires all the way into the connector on each patch. o Make sure there are no bare metal pins exposed.
  5. Put the lead wire plugs into the socket on the top of the TENS unit.
  6. Take the patches off the plastic liner. Save the liner for future storage.
  7. Place the patches on your clean, dry skin.
  8. See the pictures below to learn where to place the patches. There are 2 sets of electrodes that must be placed on the body. The first set are black in the pictures, the second set are white. You may try any electrode placement shown on these pages.
  9. The patches should not touch each other or any metal object, such as a belt buckle or metal jewelry.
  10. Turn the unit on.
  11. Follow the treatment program in your After Visit Summary.
  12. Start treatment and change the intensity to be strong but comfortable. o This may cause your muscles to contract.
  13. After a few minutes, it may seem the stimulation is less. This is normal as your body gets used to the TENS. You should turn up the intensity of the TENS unit to keep it feeling strong, but comfortable.

Images used with permission of Compass Health Brands AccuRelief Tens products.

To stop treatment

  1. Make sure the TENS unit is turned off.
  2. Carefully take the lead wires out of the patches. o Pulling or yanking on the wires could damage the electrodes.
  3. You may either take off the patches from your skin or leave them on until your next use if you are going to use it again within the next 2 hours. o If you take off the patches, gently peel them off your skin and place them back onto the plastic liner.
  4. Put the liner and patches in the plastic storage bag and store it in a cool, dry place until you use them again.

Tips for use

The patches can be used over and over, until the adhesive wears out.

  • The patches will stay sticky and last longer if you clean your skin before you start and put them back in the storage bags when you are done.
  • Patches can dry out if left out of the storage bags too long.

Patches that are dirty and/or hard to attach can be washed softly with your fingertips under slow-running, cold water, and air-dried.

Replace the batteries or recharge the unit when the low power light flashes on the display of the unit.

Attach a belt clip to the TENS unit to use it hands-free while you are active.

Cleaning and storage

To clean the unit, turn it off and take the lead wires out of the patches. Gently wipe the unit with a slightly moistened, soft cloth.

  • Do not use chemical cleaners.
  • Do not use rubbing alcohol.
  • Do not let water get inside the unit.

Store the unit and wires in a cool, dry place when you are not using it. Keep it in a place that is above -14°F and less than 131°F (-10°C to 55°C) and 90% relative humidity. Check the instruction manual for more details about your unit.

If you will not be using the unit for a long amount of time, take the batteries out so the liquid in the batteries does not leak.

Preventative maintenance

  • Do not drop the unit on hard surfaces, get it wet, or leave it in very hot or very cold places.
  • Do not bend or coil the lead wires tightly. This can damage them.

Tips for buying

There are many TENS units you can buy at local retail stores and on the internet. TENS units and electrode patches can be found on Amazon, EBay and retailers’ websites, as well as at local retailers and medical supply stores. You can also choose to ship to a retailer or your home.

Here are the key points to think about when buying a TENS Unit:


Pick a model with dual (2) channels. This will let you put on up to 4 patches.


Please note that wires connect to the patch with a pin or a snap. Patches come in many shapes and sizes. Pick the patches that will work for your area of pain. Make sure it will be easy to buy replacement patches when you need them.


Most models use alkaline or rechargeable batteries. Do not forget about the cost of replacement batteries. If you are thinking of a wireless model, make sure you can reach the buttons on the unit to raise or lower the intensity.


Some units come with belt clips or pouches to help you wear and carry the unit. You may also put the unit in your pocket. Pick what is right for you.


The costs of having a TENS unit are the TENS unit, replacement patches, and batteries as you need them. Patches may last up to 2 weeks. Choose a TENS unit that meets your needs.


Cannot feel the current

  • Turn the unit off before making changes.
  • Check the power source. Are the batteries inserted properly? Are the batteries dead or weak?
  • Check the patches. Are they all sticking on the body? You may be able to reactivate the sticky surface. Wet your fingertip with water and gently rub the patch surface. Let it dry for 60 seconds and try putting it on again. If this does not work, use new patches.
  • Check the wires. Are they plugged into the patch and unit properly?

No pain relief

  • Do not use the unit for 3 to 5 days. Then try it again.
  • Try a different setting.
  • If you have not tried this, turn up the intensity to keep the feeling strong but comfortable.
  • Try changing the position of the patches.
  • Call your health care team for help if you cannot get relief.

Skin irritation

  • Call your health care team if you have redness, a rash, or itching in the first 24 hours of use.
  • Move the patches to a different site. Do not put them on broken or irritated skin.
  • Clean your skin and let it air dry before putting on the patches.

Patches will not stay on or in place

  • Try to reactivate the sticky surface. Wet your fingertip with water and gently rub the patch surface. Let it dry for 60 seconds and try putting it on again.
  • Try using a skin prep product. This product is put on the skin before placing the patch. It helps the patches stick better. You can buy it online or at a medical supply store.
  • Sweating can cause the patches to move out of place. If this happens often and a skin prep product does not help, try to hold the patches in place with medical tape. Ask your health care team for instructions.

Frequently asked questions

What does TENS feel like?

You may feel tingling, tapping, buzzing, or muscle twitching. You may also notice the TENS feels stronger or weaker at times. You may become used to the feeling and can turn up the intensity as you wear it longer.

Does TENS hurt?

No, it should not hurt. Make sure you are setting it at a strong but comfortable intensity.

Can TENS harm my body?

No, but it can cause some skin irritation from the patches.

Can I get shocked?

The TENS unit gives a therapeutic dose of electricity to your body. The higher you turn it up, the more intense the feeling will be and the more pain relief you will get. Turning it up as high as it will go may cause surprise and discomfort, but it will not harm you.

Since the unit is an electrical device, you can get shocked if:

  • You reposition, or take off, the patches or if you remove the wires from the patches without first turning the unit off
  • The unit gets wet while you are using it
  • You touch bare wires on a damaged cord

What if a wire comes out of the unit or patches?

Turn the unit off, put the wire back in, and restart the unit.

Does it matter where I place the patches?

Yes! Try to surround the painful area. Place them on fleshy areas of the body, not over boney sites.

What if the patches fall off?

Turn the unit off and take the wire out of the patch. You can either clean and dry the patch or replace it with a new patch. In either case, make sure your skin is clean and dry before putting on the patch and restarting the unit.

Is it OK if my muscles twitch?

Yes, as long as it is not uncomfortable. Having your muscles twitch for longer than 30 minutes may cause them to get tired or sore.

Is it OK to turn it up to where I just barely feel it?

No. Research shows this will not provide pain relief.

Why do I not wear it to bed?

It is easy for the wires to get tangled or unplugged, or the patches may come off. Not wearing it to bed also lets your skin rest from wearing the patches.

Do I have to use my TENS unit daily? Can I take a break?

You can take a break; 3 to 5 days off may be helpful. If your pain is at a manageable level, you may want to leave the unit off and wait to use it again when you have a flare-up. Some people use their TENS only when their pain is most severe, while others use it daily.

Why can’t I let someone else try my TENS unit?

Just as you would not let others take a medicine that was only prescribed for you, you should not let others use your TENS unit.

What is the problem with wearing it in the shower?

There is a chance for electrical shock since it is an electrical device. Also, the unit is not waterproof and would be damaged.

Do I have to use all four patches?

No. But, if the area is large enough to get all 4 patches on, you will get more stimulation, which could give you greater pain relief.

Will my insurance cover a TENS unit?

TENS units are not routinely covered by insurance, but all companies have different policies. Please call your insurance company to find out if your plan covers a TENS unit.

Where do I get more TENS unit patches?

Look in your TENS unit manual to learn how you can get more TENS supplies. Your best choice is to go back to the vendor where you bought the unit. You may find patches on-line, but check with the vendor to be sure the patches work with your unit.

TENS Skin Prep

Some people find their TENS electrodes can slip and slide around. This can happen even if they wash and dry their skin before putting them on. In these cases, we suggest special skin preparation pads. You can buy some in the Iowa River Landing pharmacy.

Preparación de piel para usar Neuroestimulación Eléctrica Transcutánea


  1. Using water only, clean the area where the electrodes will be applied.
  2. Let skin dry.
  3. Use skin prep on the same area and let skin dry.
  4. Wash your hands so you do not get the skin prep on other surfaces or in your eyes.
  5. Put on electrodes as usual

What Does A TENS Unit Do For Muscles? (And What Doesn’t It Do?)

There are many questions surrounding the use of transcutaneous electrical nerve stimulation (TENS) units on muscles.

In short, TENS units aren’t considered to be the best and most effective tool for muscles but they can have their uses. In this article we delve into what a TENS unit does (and doesn’t do) for muscles.

Be aware, if you’re reading this there’s a chance that you’re thinking of an electric muscle stimulator (EMS) machine, a very similar looking device.

Confused About The Difference Between TENS And EMS?

Many people confuse TENS with electrical muscle stimulation (EMS). While TENS and EMS units can look almost identical, the two have completely different purposes so it’s imperative that you choose the correct type of device.


While TENS stimulates the sensory nerve endings – with the objective being to provide pain relief – EMS stimulates muscle motor nerves causing muscle contraction.

In some cases if the electrode pads are placed correctly on a muscle and used on a high setting, a TENS device may cause the muscles to twitch and contract, however this is not the intention of TENS therapy and not what the devices have been designed to do.

  • The programs on TENS machines are not created with the intention of causing muscle contractions, the way EMS programs are.

Like TechCare’s Plus 24, they tend to have names derived from massage techniques such as kneading, Swedish, and scraping, to name but a few.

In spite of that (and perhaps surprisingly) there is a body of evidence that supports the use of TENS for certain muscular conditions and situations. We’ll come onto that a little later in the article.

  • Programs on EMS units are designed to work the muscles in a particular way with specific contraction / relaxation times.

Pin it for later!

Don’t forget to pin this article about what a TENS unit does for muscles for later!

Typically, electric muscle stimulators (PowerDot being a great example) come with programs that stimulate the muscles for both exercise preparation and recovery, along with programs for strength, resistance, and endurance.

Such programs on EMS units target either or both slow-twitch and fast-twitch muscle fibers, depending on their purpose.

Then there are combination units on the market, such as iReliev’s PlayMakar that offer both TENS and EMS capabilities:

Did You Know?

Electrical Muscle Stimulation (EMS) is also known by the names: NeuroMuscular Electrical Stimulation (NMES), electromyostimulation, e-stim, and stim.

Muscle Relaxation / Tight Muscles

A study carried out in 1997 investigated the effectiveness of electrotherapy on myofascial trigger points (knots) in patients’ shoulders (upper trapezius).

It looked at how 60 people (25 males and 35 females) responded to electrical nerve stimulation, electrical muscle stimulation, and placebo treatments.

  • The study concluded that EMS was more effective for the immediate release of muscle tightness than nerve stimulation.

EMS was found to improve the range of motion, which was measured by recording a neck side bend before and after the treatment.

But does a TENS unit relax muscles?

The mild electrical impulses from TENS can reduce the pain signals going to the brain, which may relieve pain and relax muscles.

In fact, a more recent (but very small) study with fifteen healthy young males found TENS combined with stretching to be effective in reducing pain and decreasing muscle hardness, leading to an increase in range of motion.

Muscle Knots

Perhaps surprisingly to some, the aforementioned study into the effectiveness of electrotherapy for muscle knots found electrical nerve stimulation to be more effective than electrical muscle stimulation for the immediate relief of myofascial trigger point pain.

  • The study concluded that nerve stimulation was significantly better for relieving pain caused by muscle knots.

Don’t confuse this with breaking up the knotted muscle tissue though:

From my own personal experience (if it’s not practical or possible to see a physical therapist or masseuse) I have found a powerful handheld electric massager to be more effective than either TENS or EMS for getting into muscle knots.

Muscle Spasms

Physical therapists and physicians often recommend their patients try a TENS unit for muscle spasms.

According to the NHS, TENS may be able to help reduce muscle spasms caused by conditions such as: arthritis, period pain, knee pain, back pain, and sports injuries.

  • READ: TENS Unit Benefits: 20 (Life-changing) Reasons You Should Use One

That being said, solid evidence for treating general muscle spasms seems to be hard to come by, although studies have looked into TENS for specific conditions.

A big review carried out by the Center for Psychiatric Rehabilitation looked into spasticity after spinal cord injury (SCI).

The review referenced a study that used stimulation to a nerve in the leg which led to a decrease in muscle spasms, however it did go on to say further study is required to establish whether this would work in the same ways for people with different levels and completeness of injury.

Another noteworthy study used TENS to treat patients with muscle spasm after the lesion of upper motor neurone.

  • The authors reported a statistically significant decrease of muscles spasm in patients treated by TENS.
  • Stating that if longer stimulation is applied reducing of the muscle spasm is more pronounced.

Muscle Recovery

In 2007 researchers at Lagos State University College of Medicine conducted a study into the relief of Delayed-Onset Muscle Soreness (DOMS).

They examined how simple stretch exercises and trans-cutaneous electrical nerve stimulation (TENS) compared in the treatment of DOMS.

  • While TENS was shown to be effective in treating DOMS, it showed no superior benefits compared to stretching.
  • In fact stretching proved more effective in reducing muscle soreness – and compared to TENS – resulted in a greater range of motion.

A small but intriguing 2011 study looked into the effectiveness of three different between-inning recovery methods on baseball pitching performance.

The authors wanted to determine which of three forms of recovery were the most effective. They compared passive recovery, active recovery, and electromuscular stimulation (EMS).

The most notable finding was that EMS produced the highest reduction in blood lactate (lactic acid) levels. The other recovery methods had no significant effect on blood lactate.

(Reducing the amount of blood lactate post-workout is beneficial for the recovery of muscles).

  • The authors concluded the study by recommending that baseball pitchers consider employing EMS between innings as it may potentially lead to an increase in pitching performance.

Interestingly though other studies have found light exercise (such as swimming or jogging at a slow pace) to be more effective in blood lactate clearance.

An example of this being a comparison that pitted submaximal swimming against muscle stimulation after sprint swimming.

  • That particular piece of research concluded that submaximal swimming was most effective at lowering blood lactate.
  • However EMS also reduced blood lactate significantly better than resting passive recovery.

This therefore begs the question:

Why not just do light exercise for recovery and to clear blood lactate?

It’s not always practical. You may be physically and / or psychologically exhausted. It might be late at night. You may not have access to a pool.

Electric muscle stimulation can make your body produce the muscle contractions required to clear blood lactate and can be used at your own discretion, when and where you like.

  • READ: Electric Muscle Stimulator: Case Study And Machine Comparison

The Verdict

There is research that supports the use of electrotherapy for muscles (both TENS and EMS modalities). However it’s not as conclusive as we’d like. More comprehensive studies and trials would be welcome in this field.

It might just be a case of seeing for yourself, depending on your objectives. If it is something you are considering there are many inexpensive machines for TENS and for EMS.

Alternatively, for dealing with tight or knotted muscles at home it might be worth looking at an electric massager or a foam roller.

Still not sure?

You can always stick with the more traditional methods such as stretching, light exercise, and massage!

Want to find out more?

There are plenty of posts on the site about TENS and EMS. Click on the links below to see them:

Spinal cord stimulation

What are the results?

The results of SCS depend on careful patient selection, successful trial stimulation, proper surgical technique, and patient education. Stimulation does not cure the condition that is causing pain. Rather, it helps patients manage the pain. SCS is considered successful if pain is reduced by at least half.

Published studies of spinal cord stimulation show good to excellent long-term relief in 50 to 80% of patients suffering from chronic pain . One study reports that 24% of patients improved sufficiently to return to gainful employment or housework with stimulation alone or with the addition of occasional oral pain medication .

SCS therapy is reversible. If a patient decides at any time to discontinue, the electrode wires and generator can all be removed.

What are the risks?

No surgery is without risks. General complications of any surgery include bleeding, infection, blood clots, and reactions to anesthesia. Specific complications related to SCS may include:

  • Undesirable changes in stimulation (can possibly be related to cellular changes in tissue around electrodes, changes in electrode position, loose electrical connections, and/or lead failure)
  • Epidural hemorrhage, hematoma, infection, spinal cord compression, and/or paralysis (can be caused by placing a lead in the epidural space during a surgical procedure)
  • Battery failure and/or battery leakage
  • Cerebrospinal fluid leak
  • Persistent pain at the electrode or stimulator site
  • A pocket of clear fluid (seroma) at the implant site. Seromas usually disappear by themselves but may require a drain.
  • Lead migration, which can result in changes in stimulation and reduction in pain relief
  • Allergic response to implant materials
  • Generator migration and/or local skin erosion
  • Paralysis, weakness, clumsiness, numbness, or pain below the level of implantation

Conditions for which you might need additional surgery include movement of the lead, breakage of the lead or extension wire, or (in rare cases) mechanical failure of the device. Reasons for removal of the device include infection and failure to relieve pain.

Sometimes scar tissue develops around the electrode and can make the stimulation less effective.

Living with a stimulator

Once the SCS has been programmed, you are sent home with instructions for regulating the stimulation by controlling the strength and the duration of each stimulation period. Your doctor may alter the pulse width, amplitude, and frequencies on follow-up visits if necessary.

The pulse generator has programmable settings:

  1. Frequency (rate): number of times stimulation is delivered per second. Too few pulses results in no sensation. Too many results in a washboard or bumpy effect.
  2. Pulse width: the area the stimulation will cover.
  3. Pulse amplitude: determines threshold of perception to pain.

The handheld programmer lets you turn the stimulator on and off, select programs, and adjust the strength of the stimulation. Most people are given multiple programs to achieve the best possible pain relief at any point throughout the day or during specific activities. You can use your spinal cord stimulator around the clock if necessary.

Some people feel differences in stimulation intensity depending on their position (e.g., sitting versus standing). This is caused by variations in the spread of electricity as you change positions and is normal.
Just like a cardiac pacemaker, your stimulator cannot be damaged by devices such as cellular phones, pagers, microwaves, security doors, and anti-theft sensors. Be sure to carry your Implanted Device Identification card when flying, since the device is detected at airport security gates. Department store and airport security gates or theft detectors may cause an increase or decrease in stimulation when you pass through the gate. This sensation is temporary and should not harm your system. However, as a precaution, you should turn off your system before passing through security gates.
The various SCS systems have different restrictions to their use with MRI, ultrasound, defibrillator, electrocautery, diathermy, and cardiac pacemakers. Be sure to know the limitations of your specific SCS device. Also, chiropractic manipulation may cause the lead to move. Consult your surgeon first.

Sources & links

If you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100.

  1. Verrills P, Sinclair C, Barnard A. A review of spinal cord stimulation systems for chronic pain. J Pain Res 9:481-92, 2016
  2. De la cruz P, Fama C, Roth S, et al. Predictors of Spinal Cord Stimulation Success. Neuromodulation 18(7):599-602, 2015
  3. Grider J, Manchikanti L, Carayannopoulos A, et al. Effectiveness of Spinal Cord Stimulation in Chronic Spinal Pain: A Systematic Review. Pain Physician 19:E33-E54, 2016
  4. Deer TR, Skaribas IM, Haider N, et al. Effectiveness of cervical spinal cord stimulation for the management of chronic pain. Neuromodulation 17(3):265-71, 2014
  5. Deer TR, Mekhail N, Provenzano D, et al. The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee. Neuromodulation 17(6):515-50, 2014
  6. Eldabe S, Buchser E, Duarte RV. Complications of Spinal Cord Stimulation and Peripheral Nerve Stimulation Techniques: A Review of the Literature. Pain Med 17(2):325-36, 2016
  7. Sundaraj SR, et al: Spinal cord stimulation: A seven-year audit. J Clin Neurosci 12:264-270, 2005



laminotomy: surgical cutting of the laminae or vertebral arch of the vertebra.

lead: a small, silicone coated medical wire that has electrodes at one end. Electrical current passes from a battery, along the wire, to the electrodes. Two types: percutaneous and surgical leads.

fluoroscopy: an imaging device that uses x-ray or other radiation to view structures in the body in real time, or “live”. Also called a C-arm.

percutaneous: by way of the skin (e.g., injection).

peripheral nerve stimulation: a surgical treatment for pain in which specific nerves are stimulated rather than the general area of the spinal cord.

sciatic nerve: nerve located in the back of the leg which supplies the muscles of the back of the knee and lower leg and sensation to the back of the thigh, part of the lower leg, and the sole of the foot.

sciatica: pain that courses along the sciatic nerve in the buttocks and down the legs. Usually caused by compression of the 5th lumbar spinal nerve.

seroma: a mass formed by the collection of tissue fluids following a wound or surgery.

spinal hygroma: an accumulation of cerebrospinal fluid under the skin, which produces a visible swelling, caused by leakage around a catheter, drain, or shunt.

updated > 3.2019
reviewed by > Tann Nichols, MD, George Mandybur, MD, Marc Orlando, MD, Mayfield Clinic, Cincinnati, Ohio

Mayfield Certified Health Info materials are written and developed by the Mayfield Clinic. We comply with the HONcode standard for trustworthy health information. This information is not intended to replace the medical advice of your health care provider.

All About Electrotherapy and Pain Relief

If an individual is not experiencing sufficient control of pain and other symptoms, electrotherapy—a treatment that directs mild electrical pulses to the problem area—may be an option.

See Chronic Pain Coping Techniques – Pain Management

Electrotherapy includes a range of treatments using electricity to reduce pain, improve circulation, repair tissues, strengthen muscles, and promote bone growth, leading to improvements in physical functioning.


Electrotherapy units usually consist of a battery-powered device connected by wires to adhesive electrode pads which are placed on the skin. The electrode pads are sticky, so they will adhere to the skin. Once the electrodes are attached and the unit is turned on, a mild electric current is sent to the skin via the electrode.

A number of newer electrotherapy devices bypass the wires, combining electrodes and battery power into a single unit that can be worn inconspicuously on the back, arm, leg, or elsewhere during work or other daily activities. A hand-held controller is used to adjust the level of stimulation.

While a large number of people find electrotherapy helpful, others do not. The medical literature on electrotherapy’s effectiveness has been mixed, and not all electrotherapy treatments are supported by research.

In This Article:

  • All About Electrotherapy and Pain Relief
  • How Electrotherapy Works to Ease Pain
  • Transcutaneous Electrical Nerve Stimulators (TENS)
  • Percutaneous Electrical Nerve Stimulation and Electrical Muscle Stimulation
  • Other Electrotherapy Treatments

Electrotherapy devices range in cost from less than $30 to hundreds of dollars. Several of the newer products are available over the counter, offering flexibility for those who can afford them. Devices sold without a prescription are often not covered by insurance, but people with health savings accounts may be able to apply funds from these accounts toward the cost. Trying electrotherapy in a medical or physical therapy setting before purchasing a unit may be helpful, since the therapy does not work for everyone. In some cases, a device can be returned if the treatment is not helpful, so saving the receipt is advised.

The Food and Drug Administration (FDA) verifies that these medical devices are safe to use, but does not test whether the devices are effective. Interestingly, the FDA process for approving a medical device is less rigorous than the approval process for drugs, which requires the pharmaceutical company to show evidence of a drug’s effectiveness before introducing it to the market.

When Electrotherapy Is Advised

Electrotherapy is typically used in conjunction with other treatments, rather than by itself. For people undergoing physical therapy, electrotherapy may alleviate pain sufficiently for an individual to participate more actively in targeted exercises. Electrotherapy is among pain relief options gaining attention as the potential risks and side effects of opioid (narcotic) medications have become more apparent.

See Opioid Medication Potential Risks and Complications


Efforts to use electrical current to aid in healing go back to ancient times. The modern era of electrotherapy in the United States began with treatment for anxiety and depression, and the number of potential uses has grown since. Electrotherapy has been used to address chronic pain and chronic fatigue in general, as well as:

  • Diabetic nerve pain
  • Fibromyalgia
  • Migraine headaches
  • Wound healing
  • Stimulating bone growth

See Chronic Pain As a Disease: Why Does It Still Hurt?

Electrotherapy can take many forms, but the most common type is transcutaneous electrical nerve stimulation, or TENS.

Compass Health Brands has revealed seven new TENS, EMS and Massage technology devices at CES 2017.

The pain relief devices provide Transcutaneous Electrical Nerve Stimulation (TENS) and Electrical Muscle Stimulation (EMS) therapy.

Using electrodes, “the electrical impulses are sent through the skin to the nerves to modify pain perception,” according to AccuRelief. Nerve pathways are blocked by the pulses, preventing the brain from receiving pain signals and providing relief.

Prototypes are available for preview at CES.

Journalists attending can rent the AccuRelief™ Remote Control Wireless to relieve soreness from exploring the show. The system uses a RF/wireless compact electrical TENS unit to target the needed area. Two reusable gel pads are used around the sore area, releasing the electrical impulses with a Bi-phase square pulse wave form.

The device operates on a frequency of 5~125Hz and a pulse width of 130/250 μS.

Users can control electrical pulse intensity with the remote.

Users with pacemakers, implanted defibrillators other metal implants, or other life-supporting medical electronic devices are not advised to use this product as it can lead to electrical interference.

AccuRelief™ Wireless Remote Control TENS Pain Relief System (Credit: AccuRelief)

Another device is the AccuRelief™ Single Channel TENS Pain Relief System .

This FDA Cleared Class II Medical device also includes a lead wire, two electrode pads, and is controlled with an ACRL-2000 unit controller that includes an output socket, connecting the electrode pads to the controller. It operates on a frequency of 2Hz~150Hz and a pulse width of 50µs~300µs.

Six therapy programs are offered with 25 intensity levels

“We are so excited to participate in CES 2017 and to have the opportunity to unveil our new pain management devices,” said VP of Marketing – Retail, Jeff Swain. “Compass is leveraging its 30 years of TENS expertise in the launch of its new, cutting-edge, over-the-counter TENS therapy devices. Because of America’s pain epidemic, we’ve been working hard to innovate new devices that will help consumers better manage their pain and use technology to seamlessly integrate effective treatments into their daily lives. CES is the perfect place to launch this latest technology. We see such amazing potential to really make a significant impact on the quality of life for those affected by chronic pain.”

Transcutaneous Electrical Nerve Stimulation (TENS)


Transcutaneous Electrical Nerve Stimulation (TENS) is a noninvasive device placed on the skin that can help control pain. Use of this small, battery-operated device can block pain signals from reaching the brain and potentially reduce pain medication. It is important to remember that TENS does not cure or eliminate the cause of pain and is not effective for every patient.

Electrical pain control involves the use of a mild electrical current, which blocks or masks the transmission of pain signals to the brain and also stimulates the release of endorphins—the body’s own pain-killing chemicals. The electrical impulses are sent to the nerves through electrodes placed on the skin surface near the painful areas.

The electrical impulses cause a tingling sensation, which should be pleasant. It should be at a level that feels comfortable, causes no muscle contractions, and produces pain relief. Pain relief varies by individual patient and the type of pain.

Who is a candidate for TENS?

TENS is an option for a variety of conditions that cause pain. Your doctor or physical therapist can determine if you are a candidate for TENS.

The stimulation system

Indicator lights: An indicator light is located in the unit to show the pulse rate and that the unit is functioning. Make certain your power source—battery pack or batteries—is securely inserted in the unit. If no intensity is felt, even at high ranges of intensity, new batteries are usually needed. Turn off the TENS unit completely whenever removing it. The light should go out.

Electrodes: Adhesive electrodes are designed for your convenience. No gel or tape is required. If you feel itching or burning from the area of the electrodes, remove the electrodes.


  1. Rate – number of pulses per second (set by the therapist).
  2. Amplitude – intensity of stimulation (adjustable, should be comfortable).

Troubleshooting – If no current is felt…

  • Power source making no contact. Secure in place.
  • Power source insufficiently charged.
  • Internal break in TENS unit. Contact the manufacturer or company representative.
  • Wrong amplitude knob used for single channel operation.

Intermittent break in current…

  • Break in lead wire. Replace the wire.
  • Power source making incomplete contact. Secure power source.
  • Electrode not securely in place. Replace the electrode.
  • Wire not plugged into machine securely.

Uncomfortable, burning sensation…

  • Inadequate water/gel supply on electrodes. Replace the electrode.
  • Electrode not securely in place. Secure the electrode or replace.
  • Intensity too high. Turn down to comfortable level.

The TENS device is provided for the current pain condition. If other symptoms of pain occur at a later time, the patient should notify their physician.


If you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100.

updated > 4.2017
reviewed by > Lisa Cleveland, PT, Matthew Merz, MD, Mayfield Clinic, Cincinnati, Ohio

Mayfield Certified Health Info materials are written and developed by the Mayfield Clinic. We comply with the HONcode standard for trustworthy health information. This information is not intended to replace the medical advice of your health care provider.

Pro athletes endorse them and diehard gym rats swear by them. But should you bother with those pricey electric muscle stimulation machines you see popping up everywhere from Instagram to sporting goods stores?

Before you stick a set of electrodes on and crank up the dial, it’s worth understanding how electric muscle stimulation (EMS), a.k.a. neuromuscular electric stimulation (NMES), actually works. When attached to the skin, the typical EMS unit delivers an electrical impulse to the body’s motor nerves that causes rapid muscle contractions, hence all the twitches and spasms. Makers of these devices claim that the contractions can help speed up recovery time, relieve pain, increase muscle strength, and even improve performance.

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To a certain extent, those assertions are accurate. C. Shanté Cofield, D.P.T., founder of The Movement Maestro and host of the Maestro on the Mic podcast, explains that muscle contraction is one of the most effective ways to reduce swelling and inflammation, two things that any runner is bound to encounter at some point during their training. “EMS can be a great way to help with recovery, particularly in runners, because the muscle pumping activity can help with circulation and decrease swelling in the lower limbs without requiring additional impact or exercise,” she says. “The last thing you want to do after a 20-mile run is calf raises or ankle pumps. This provides a nice way to allow for recovery without additional activity.” And the faster you can recover, the sooner you can get back to your training schedule.

However, if an injury is at the root of your post-run swelling, EMS won’t fix it. At best, it will temporarily reduce pain, thanks to a process known as the pain gate theory. Cofield explains that e-stim units, specifically transcutaneous electrical nerve stimulation (TENS) machines, which target the sensory nerves versus the motor nerves, “provide a competing stimulus in the painful area that basically distracts the brain and causes the nervous system to pay attention to that stimulus instead of any other stimuli.” This is why those vibrating foam rollers tend to feel less painful than traditional rollers. For those annoying aches and pains that pop up on occasion—a tight back muscle or an ITB syndrome flare-up—15 minutes with a TENS unit (or an EMS machine on a low setting) is a good non-steroidal, non-invasive option for pain management. But it’s not a long-term solution for a chronic issue. “A distraction is not a cure,” Cofield says. “Treat the symptoms, but you must always go back and find the cause.”

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Marketers’ promises that EMS machines strengthen muscles also come with their fair share of caveats. Yes, EMS can improve muscle strength, Cofield says. “If you can train more muscle fibers to fire at a given time, you will be able to produce more force,” she says. But the most significant gains are typically seen in a rehab setting among post-operative patients dealing with severe muscle atrophy and lack of coordination, not the everyday athlete interested in bench pressing more weight or shaving time off their 5K PR. And if you’re looking to gain muscle mass, stick to heavy lifting and protein shakes. “EMS doesn’t provide enough resistance to cause muscle hypertrophy,” Cofield says.

In short, EMS won’t make you a better runner or stronger athlete. But, by supercharging your recovery time, it may allow you run more and train harder—at a cost. With machines costing several hundred bucks, it’s definitely an investment, but as our test editor Dan Roe points out: Average the price out over 12 months, and it’s less than a monthly massage—after year one, the math starts to make sense. Ready to see what all the buzz is about? Here are three of the most popular units from the biggest players in the e-stim game.

3 Popular EMS Options

Marc Pro Recover & Condition marcpro.com $699.00

The Marc Pro’s basic unit (you can upgrade to the Marc Pro Plus for an extra $300) powers four electrodes (two per intensity dial) and delivers the brand’s patented “dynamic decaying waveform” technology, which promises to recruit muscle fibers without causing fatigue. Each machine is packed in a travel case and comes with a charger and six sets of reusable electrodes.

PowerDot 2.0 Duo amazon.com $299.00

Users control the PowerDot’s two rechargeable pods, each of which connects to two electrode pads, with a free app that includes over 10 different muscle stimulation programs. In addition to the pods and electrodes, the unit includes two USB charging cables and a compact carrying case.

Compex Wireless USA 2.0 Muscle Stimulator with TENS Kit amazon.com $501.99

In addition to providing EMS, this Compex device offers TENS technology, which targets the sensory nerves and provides an analgesic effect for athletes seeking pain relief. The unit comes with two sets of pods, 12 electrodes, a charging station, and a carrying case.

Guide to Electrical Stimulation

Electrical stimulation therapy is a therapeutic treatment with a multitude of uses. It can help prevent atrophy and build strength in patients with injuries. It can be helpful in restoring function and reducing edema, especially after a stroke. In electrical stimulation, non-invasive electrodes are placed on the patient’s skin, causing the targeted muscles to contract. A mild electrical current is sent to an area of the body that is receiving confused, few, or no signals from the brain after a stroke. This stimulates the body’s inner electrical system, inducing new connections to be formed in the brain and, in turn, allowing for greater control of the particular area of the body. Electrical stimulation works by mimicking the natural way the body exercises its muscles. With electrical stimulation, the patient is able to maintain muscle tone and strength that would otherwise waste away from lack of usage.

Electrical stimulation therapy has given patients with neurological damage a better quality of life. In cases of spinal cord injury or stroke, patients are often left with pain and the inability to use parts of their bodies. Electrical stimulation can revive connections in the nervous system over time so that controlled mobility is regained and chronic pain relieved. Electrical stimulation for stroke survivors wakes up the damaged areas of the brain so that they can be reconnected with other parts of the body. Repetitive treatments can potentially nudge these areas back to life, giving stroke survivors renewed ability to use limbs or suffer less pain.

Benefits of Electrical Stimulation for Recovery

There are many benefits to electrical stimulation therapy for stroke patients. Therapists and doctors alike find that this therapy works in many different ways to benefit stroke survivors.

When muscles become paralyzed after stroke, electrical stimulation can help facilitate movement, which is critical for recovery. There is a multitude of electrical stimulation types. Some devices are wearable and incorporate electrical stimulation to help promote functional gains during regular daily life. The stimulation from electrical stimulation can also potentially help improve sensory issues after stroke. Examples of sensory issues include numbness, tingling, hot/cold sensations, or any abnormal sensations. Additionally, electrical stimulation can be a way to limit atrophy in immobilized extremities and can also be useful for improving strength after a period of disuse.

In addition to sensory issues, stroke patients can also face challenges due to edema. Edema is the buildup of excess fluid in tissue cavities and can be difficult to prevent, particularly in patients that are immobile. Fluid buildup can occur for a number of reasons, but it is especially common in stroke survivors who have lost the use of a limb. The muscles in the limb become dormant and are unable to move fluid properly through the lymphatic system. The limb then becomes a sink for this fluid. After a stroke, a survivor can often feel pain. Electrical stimulation contracts the muscles to get the fluid moving and eventually eliminated from the body. Electrical stimulation produces endorphins, calms muscles and can potentially help alleviate chronic and mild pain.

Muscle spasticity is also a common problem for stroke survivors. Muscle spasticity is a frequent complication of central nervous system (CNS) lesions, and it is commonly identified in the following ways:

  1. The involved muscles develop a resistance to being stretched.
  2. This resistance increases with the rate of stretch.
  3. The involved muscle groups also exhibit exaggerated reflexes.

Spasticity is generally considered to be detrimental to the patient. Spasticity can lead to contractures, dislocation of joints, and can mask volitional control in case of paralysis. Electrical stimulation not only relaxes the contracted muscles, but it can potentially rewire the nervous system to restore proper control over these body parts.

Types of Electrical Stimulation

There are multiple types of electrical stimulation used in the treatment of patients with neurological damage and disorders. The terms commonly used for this type of treatment are:

  • EMS (Electrical Muscle Stimulation)
  • NMES (Neuromuscular Electrical Stimulation)
  • FES (Functional Electrical Stimulation)
  • TENS (Transcutaneous Electrical Nerve Stimulation)
  • ETS (EMG Triggered Stimulation)
  • RETS (Reciprocal EMG Triggered Stimulation)

The terms EMS and NMES, in a broad sense, are similar in that they are both used to describe the stimulation of muscular tissues via electrical impulses. NMES is the common term used for electrical stimulation therapy for stroke survivors, and the terms FES, ETS and RETS all fall under the NMES category.

FES is commonly used when a patient is working to regain the use of a paralyzed body part so that function can be improved or restored. For example, improving a hand to better grasp utensils for feeding.

ETS is used in the treatment of limbs that are still receiving a partial signal from the nervous system. The ETS device detects this and is prompted to give a pulse when it occurs.

EMG or electromyogram-triggered stimulation is a combination of biofeedback and stimulation. It is based on the client’s own voluntary muscle activity or intentional movement. This “volitional”-based application requires the patient to actively participate (i.e., contract a muscle) in order to receive stimulation to the area.

RETS Reciprocal EMG-Triggered Stimulation is ideal for patients with increased tone that have difficulty relaxing or “shutting off” the spastic muscles. Stimulation is triggered to the desired muscle group (i.e., finger extensors, elbow extensors etc.) when the client relaxes the opposing hypertonic muscle group (i.e., spastic finger flexors, elbow flexors etc.). Therefore, the emphasis is placed on relaxing the hypertonic muscles in order for stimulation to be triggered to the opposing weakened muscle group.

TENS is predominately used for pain relief, pain management/treatment, and nerve-related pain conditions (acute and chronic conditions). TENS machines work by sending electronic stimulating pulses across the surface of the skin and along the nerve strands. The stimulating pulses help prevent pain signals from reaching the brain. TENS also also helps stimulate the body to produce higher levels of its own natural painkillers, endorphins.

Electrical Stimulation Is Not for Everyone

Electrical stimulation works for many patients with neurological damage, but it is important to be aware of the cases in which this type of treatment should not be used. Electrical stimulation therapy is unsafe for people using a cardiac pacemaker or defibrillator.

Areas of the body that should not be targeted with stimulation electrodes are:

  • Neck
  • Over the heart
  • Any area that could target the womb if the patient is pregnant, such as the front or back abdomen
  • Exposed cancerous lesions such as melanomas
  • Exposed or appended metal such as staples, pins, or external fixators

Electrical Stimulation Devices for At-Home Use

Saebo has developed electrical stimulation devices for patients to use in a rehabilitation environment, as well as in the comfort of their own homes.

The Saebo MyoTrac Infiniti is a comprehensive and portable advanced biofeedback electrical stimulation system designed for orthopedic and neurological patients. The advanced biofeedback triggered stimulation programs (EMG-triggered stimulation and Reciprocal EMG-triggered stimulation), along with the revolutionary foot drop treatment application, make the Saebo MyoTrac Infiniti a one-of-a-kind device. It is based on the client’s own voluntary muscle activity or intentional movement. This “volitional”-based application requires the client to actively participate (i.e., contract a muscle) in order to receive stimulation to the area. The clinician will set a prescribed threshold that the client must reach when activating his or her muscles. Once the client exceeds the preset level, he or she is rewarded with stimulation to the same muscles. Visual and auditory feedback allow the client to monitor progress. Through this cognitive relearning process, cortical plasticity can be achieved.

The SaeboStim Micro provides low-level sensory electrical stimulation (SES) to the arm and hand using a specialized electro-mesh hand-and-forearm garment. This device delivers a low level electronic pulse that will not cause muscle contractions, but will help alleviate pain and edema, all while keeping the connection between muscle groups and the brain open. The SaeboStim Micro can also decrease spasticity, improve motor function, increase sensation, and improve inattention and neglect.

Electrical Stimulation Can Help A Survivor

Electrical stimulation therapy is innovative and accessible for survivors dealing with pain or weakness as a result of a stroke. Devices like the Saebo MyoTrac Infiniti and the SaeboStim Micro are great tools for stroke survivors seeking the pain relief and neuromuscular reeducation benefits of electrical stimulation therapy in the comfort of their own homes.

All content provided on this blog is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your doctor or 911 immediately. Reliance on any information provided by the Saebo website is solely at your own risk.

How do e-stim machines work and how effective are they?

They deliver electrical stimulation, which can reduce pain and increase blood flow, but how much of a difference they make varies based on the situation. There are two ways they tend to work: You may see NMES (neuromuscular electrical stimulation) or EMS (electrical muscle stimulation), which means the therapy is designed to stimulate motor neurons—“the nerves that control the muscle,” Dr. Melepura explains. Whereas TENS (transcutaneous electrical nerve stimulation) units are designed to stimulate sensory neurons, aka “the nerves that transmit the pain.” Physical therapist Best explains the former (NMES/EMS) is intended for “someone having trouble contracting the muscle itself.” For example, after a knee injury, it could help prevent atrophy in your quad muscle. TENS, on the other hand, is used only to reduce pain.

How do home ones differ from what pros use?

“While there are many electrotherapy devices available, their basic function is the same,” Dr. Melepura says, as is their efficacy. “Some stimulators are simplified and have preset stimulation settings (frequency, amplitude and duration) for different body parts. The user just pushes a button that corresponds to the part of the body that they want treatment for.” Best says the in-office machines may have more potential settings—but a simple device, even one that only offers TENS, is suitable for most people for home use.

Should a runner who has recurring issues, like lower back pain or Achilles tendinitis, use this therapy?

“People do tend to self-medicate,” Best says. “If you read the directions and you understand what’s going on, they can definitely be very beneficial. In our practice, it’s commonly used as a modality at the end of treatment, because a lot of times people have increased pain, and it calms everything down so that they feel better.” For in-office patients who say e-stim is particularly beneficial, she has recommended a home unit.

If a runner tweaks a muscle or has some acute pain, does it make sense to use e-stim without seeing a doctor first?

It’s up to the individual, but Dr. Melepura says, “The best initial treatment is rest, applying ice or cold compresses and elevating the injured body part. Some injuries will need additional treatment, so if the pain persists for a week to 10 days, individuals should seek the care of a physician who will be able to recommend if electrotherapy is appropriate.”

Should a home treatment feel the same as with a professional?

Yes. Since you can crank up the electrical stimulation on your own, Best says, “You want it to be a moderate feeling but not painful or uncomfortable.” She also suggests treatment for 15 to 20 minutes at a time, and you can use ice with it to help reduce inflammation.

Going Shopping

We found a lot of different machines, so here are three questions to ponder:

  • Do I want both the option for EMS (for acute injuries) and TENS (to reduce pain)?
  • How important is ease of use and would I be apt to try this without professional advice?
  • How much do I want to pay? We found a simple TENS unit as low as $17 and a combo EMS/TENS unit around $70 through TENS Pros.

Warning Signs

Dr. Melepura offers these tips.

  • TENS and EMS should not be used on vital parts, such as across the neck, chest or brain (and not at all if you have a pacemaker).
  • Electrical stimulation should be used with caution during pregnancy or when trying to conceive.
  • There is a potential of skin irritations and possibly burns if used excessively.

FAQs for Electrical Muscle Stimulation (EMS)

Read the following FAQs for EMS (electrical muscle stimulation) or NMES (neuromuscular electrical stimulation) to learn more about this athletic training enhancer and rehabilitation technology.

What Is Electrical Muscle Stimulation or EMS?

Electrical Muscle Stimulation (abbreviated EMS) is the use of electrical impulses to cause muscle contractions. Also known as electromyostimulation or neuromuscular electrical stimulation (NMES), it is a tool used by body builders, athletes and physical therapy patients to strengthen muscles with a electrical charge, not by traditional contraction methods caused by the user from the nervous system. During EMS the electric charge is sent via electrodes attached to the skin surface.

What Does Electrical Muscle Stimulation Do?

EMS or electric muscle stimulation causes a real muscle contraction as electrical impulses are sent to the body. This contraction is the same as one caused by a patient or user. In effect, it mimics the contraction of your muscles by your central nervous system. It can strengthen and tone muscles that are not in use, or able to be used due to injury. It can also increase the time a muscle can be contracted, to strengthen, tone and tighten muscle fiber.

What Is a Muscle Stimulator?

An electric muscle stimulator is a device that sends electrical impulses to the body during EMS. There are many different types of muscle stimulators from basic units that can be used at home to more complex units used for intense work outs, elite body building and physical therapy. Some units have multiple channels, highly sensitive settings and advanced technology to improve performance.

What Does An Electrical Muscle Stimulator Do?

The muscle stimulator creates the electrical charge to cause the muscle contraction inside the body. Most devices send a specific charge that can be adjusted in intensity and length (time the charge lasts) through electrodes that are applied to the body. The electrodes can be applied anywhere. Only muscles near the electrodes will contract. Users apply the electrodes to the body part they want to work.

What Are The Side Effects Of Electrical Muscle Stimulation?

There are few side effects of EMS or NMES. These include skin irritations at the site of the electrode application. Headaches and other irritations or painful sensations can also occur when the unit is applied near the head and neck area. Painful muscles may occur if the units are used on afflicted joints or atrophied muscles, or muscles with other types of common issues like spasms. Using the units in excess may also cause pain in the muscles and joints.

What are the Benefits of EMS (Electrical Muscle Stimulation) or NMES?

EMS has many benefits to athletes. It enhances power, performance and muscular enhancements. However, the device must be used properly in a complete and targeted work out routine. The benefit is enhanced or optimized training that does not require additional central nervous system input from an athlete that may already be tired and not have the energy to perform at high a level in their workout.

How to Use an Electric Muscle Stimulator

The muscle stimulator must be used in a constructive and planned workout or therapy routine. This ensures the best possible results. Using the device during a structured workout with targeted goals and milestones typically uses the best results. The device should be used on a targeted muscle group during or along with the workout.

Where to Place Muscle Stimulator Pads?

Electronic muscle stimulator or NMES pads should be placed on the skin over the are you want to target. If you are targeting quads, place the EMS electrodes on the quad muscles directly on the skin. To target biceps, place the electrodes on the bicep muscle. It is also important to use the right sized pad for your muscle group.

What Are Muscle Stimulators Used For?

The EMS or NMES device is used to enhance athletic training, body building, and rehabilitation or recovery. It can be used to work muscles harder and longer than an athlete can normally work them, simply because of fatigue and mental wear. The machines may also be used to prevent muscle atrophy in patients who have immobilized limbs or limited movement of a limb.

How Long Should You Use Electrical Muscle Stimulation?

The EMS unit should not used excessively. Each athlete has their own limitations for how long a contraction can occur. When using the device, be sure to consult with a professional trainer and use the device within reason to achieve your specific goals.

Where Can I Buy A Muscle Stimulator

Muscle stimulators are available online at stores that specialize in selling these particular devices. You can shop for an EMS unit here.

Can You Use EMS and TENS Together?

Yes, you can use both. It is not advisable to use them at the same time, but they can be used on the same patient or individual. There are devices that combine both the muscle contraction of and EMS unit with the pain relief of a TENS device. These combo TENS EMS units should be used with after consulting your doctor.

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How Electrotherapy Works to Ease Pain

While the concept of using electricity on the body may sound painful, many people find the sensation relaxing. With TENS, for example, the individual experiences a tingling, vibrating, or buzzing sensation.

The exact mechanism of electrical stimulation’s beneficial effect remains controversial. Electrical stimulation may directly block transmission of pain signals along nerves. In addition, electrical stimulation has been shown to promote the release of endorphins, the natural painkillers produced by the body.

See Therapeutic Nerve Blocks for Neuropathy


Electrotherapy Side Effects

The most common side effect with electrotherapy is skin irritation or rash, caused by the adhesives in the electrodes or the tape holding the electrodes in place. Overusing electrotherapy may cause a burning feeling in the skin. Directions about the duration of therapy should be followed closely to avoid a problem.

Electrical stimulation should not be applied over malignancies or areas with broken skin or an infection. Bruising, bleeding, or infections are possible with the types of electrotherapy that penetrate the skin.

Placing the pads over the heart or over pacemaker leads could cause cardiac arrhythmia and placing them over a pregnant woman’s abdomen could cause fetal damage. In fact, people with pacemakers and pregnant women are generally advised to avoid electrotherapy altogether.

See Management of Back Pain in Pregnancy

Placing the pads over the throat could cause low blood pressure. Using electrotherapy while driving is not recommended.

In This Article:

  • All About Electrotherapy and Pain Relief
  • How Electrotherapy Works to Ease Pain
  • Transcutaneous Electrical Nerve Stimulators (TENS)
  • Percutaneous Electrical Nerve Stimulation and Electrical Muscle Stimulation
  • Other Electrotherapy Treatments

Types of Electrotherapy

All electrotherapy devices have certain similarities, such as using battery power to apply current to electrodes. The therapies vary in frequencies, waveforms, and effects, however. These are some of the most commonly used kinds of electrotherapy:

  • Transcutaneous electrical nerve stimulation (TENS)
  • Percutaneous electrical nerve stimulation (PENS)
  • Electrical muscle stimulation (EMS)
  • Interferential current (IFC)
  • Pulsed electromagnetic field therapy (PEMF)
  • Galvanic stimulation (GS)


Ultrasound and laser therapy are often grouped with electrotherapy, or the wider category of electro-physical agents, despite not delivering an electric current. With ultrasound, sound waves are directed to the affected area to speed up the healing process. Laser therapy may also be used to help tissue heal, and provides a more targeted and intense treatment.

See Cold Laser Therapy Pain Management Treatment

Interferential current (IFC) therapy is a therapeutic modality that is used often in an orthopedic physical therapy setting. The following article serves as a brief introduction to the modality and it’s uses.

A piece of equipment commonly used by physical therapists is the interferential current machine. This machine produces electrical currents (~4000HZ) that pass through the affected area of the patient. The current tends to penetrate deeper than other electrical modalities and has a number of physiological effects that have therapeutic value.

The physiological effects of IFC

The physiological effects include:

1. an increase in localized blood flow which can improve healing by reducing swelling (the additional blood flowing through the area takes edematous fluid away with it) and as a result helps remove damaged tissue and bring nutrients necessary for healing to the injured area

2. the stimulation of local nerve cells that can have a pain reducing/anaesthetic effect due to potentially blocking the transmission of the pain signals (pain gate mechanism) or by stimulating the release of pain reducing endorphins (opiod mechanism)

3. some degree of muscle stimulation as muscle contraction can be achieved through external application of an electrical current, overcoming some of the muscle inhibition often caused by local injury and swelling

The electrical current is applied to the affected area using four electrodes. The four electrodes are placed in such a way that the two currents produced cross each other in the affected area. For example, if it is a knee injury that is being treated, the two currents can be applied so that they cross deep within the actual knee joint itself. Where the two currents meet, they actually ‘interfere’ with each other; hence the name ‘interferential.’

Should the Patient Feel Interferential Current?

The patient should not feel any discomfort from the application of the interferential current. The electrodes will usually be used with a damp sponge placed between the electrode and the patient’s skin. If discomfort is felt it is usually because an electrode sponge is not damp enough or because the sponge is not entirely covering the electrode and therefore is allowing some direct contact between a portion of the electrode and the skin.

During treatment patient will feel a tingling or ‘pins and needles’ sensation at the contact area of the sponges and may also feel the tingling sensation throughout the area being treated. This sensation may continue for a brief period following treatment as well. The intensity of the current should be increased within the patient’s comfort level. A stronger current will usually have a more beneficial effect but the intensity should not be turned up so high as to cause pain.

Interferential Current (IFC) Equipment on Shoulder

Safety and Contraindications

IFC has been used in physical therapy treatment for many years and has been proven to be very safe. However, use should be avoided on individuals with pacemakers and near the low back or abdomen of pregnant women. You should also avoid the use of this modality in a body part where there is any possible risk of metastasis.

Here are some other articles you may be interested in:

  • Therapeutic Ultrasound
  • Measuring Pain

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