Can I Use a TENS Unit for Muscle Building? Not Exactly…

Geoffrey Lions
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What exactly is a TENS unit?

Transcutaneous electrical nerve stimulation (TENS) machines are low-voltage electrical devices that send tiny pulses of energy through the skin to your nerves. They’re used to stimulate the nerves and lessen pain.

Do TENS machines increase muscle growth? Yes and no. It’s important to understand the limits of TENS in order to answer that question.

TENS Units Decrease Pain Caused by Exercise

Decreasing temporary pain caused by exercise is a big part of how a TENS machine works. They can’t eliminate the pain entirely, but they’ll make it better.

Muscle growth occurs during the recovery period that happens after you exercise, which usually refers to the time after your muscles are sore. Because a TENS machine provides pain relief, the recovery period is better. You’re much more likely to continue exercising regularly when you’re using a TENS machine, and the benefits are much more noticeable.

Can a TENS unit help to build muscle?

A TENS unit (Transcutaneous Electrical Nerve Stimulation) delivers electrical impulses to the nerves through the skin. These impulses can help to reduce pain and increase the production of endorphins, which can have a positive effect on how you feel. TENS is usually used to treat chronic pain, such as pain from arthritis or back or joint pain, and is also sometimes used for some post-surgical pain.

How a TENS unit is used in regards to muscle building is that the unit sends electrical impulses to the muscle that has been worked, which is how it reduces the level of pain that is felt during and after the workout.

This process of using a TENS unit during a period of strenuous physical activity isn’t really muscle building per se, but it can help to aid muscle recovery in a similar way. By reducing levels of pain in the muscle, the muscle is able to repair itself more quickly. Without muscle recovery, further strengthening work can be taken much more slowly.

TENS units can also be used to reduce the chances of injury from over-training and to help you maintain a higher level of strength. After a period of strenuous activity, TENS pulses can be used to increase the flow of blood to the area being worked and to speed up the recovery process of the muscles and joints.

How does Electric Muscle Stimulation (EMS) work?

Essentially, the body is a complex machine and electric muscle stimulation (EMS) is a way to send signals to the body to control its overall function and to increase muscle power. Research has shown that muscle stimulation increases the rate of muscle tearing, which then leads to bigger muscles.

EMS stimulates the body’s muscles with an electric signal. The muscle signals are sent to the brain, where they are interpreted and processed.

Electrical stimulation can be applied to either a large number of muscles or to just one muscle in the body. The signals are sent to the muscle and can either train the muscles to perform better or can stimulate the body’s own recovery process.

The signals sent to the muscles can be the same as those sent through nerve cells and can be compared to those that the receiving cells integrate to activate the muscle.

Alternatively, the signals can be electrical pulses specific to the muscle cells. On the surface of the muscle cells there are receptors that are activated when enough electrical pulses reach them. This is way EMS works.

Varying the rate of the pulses changes the stimulation pattern in the muscle, thus providing an area of muscle stimulation that can be used to perform for a sustained period or to enhance muscle power.

What’s the difference between TENS and EMS?

TENS units go a step further than EMS. They send pulses through some device that can be worn over the part of the body that you want to treat. TENS stands for transcutaneous electrical nerve stimulation. TENS units are used to treat lower body pains like sciatica, and they are also very effective at treating joint and muscular pains [1].

TENS units come with multiple modes, such as the muscle stimulation mode. The multiple modes allow you to choose just how and where you want your pain alleviated. [2] EMS stands for Electrical Muscle Stimulation. EMS devices are worn over the part of body that’s being treated and send electrical pulses that are specifically designed to boost muscle mass. [3].

EMS and TENS do the same thing. They send constant electrical impulses to the part of the body that’s being treated. The difference is that EMS devices are used to create stronger, firmer muscle. [4].

FDA regulation of Electric Muscle Stimulators

Products that fall under this product class must be approved by the United States Food and Drug Administration (FDA). This requirement applies regardless of whether the product is marketed as a medical device or a personal use product. Many such products have been approved through the FDA’s 510(k) premarket notification pathway. Not all.

When a non-medical device is marketed based on FDA approved or cleared medical device, it is important not to imply that the non-medical device is approved, cleared or works exactly like the medical device. They are different devices with different intended uses and different mechanisms of action and should not be treated or marketed alike.

The FDA’s regulation applies to products claiming their use based on efficacy, safety, performance, pain relief, speed of recovery, strength, and muscle length increases.

The benefits of EMS for muscles

Electrical muscle stimulation, EMS, is often used as a way to prevent muscle atrophy due to disuse. For example, if you have an injury and need to limit activity or use a wheelchair, EMS can be used to help delay the muscle loss that comes with that.

Some studies have even shown that EMS can help improve muscle function in people with permanent disabilities. This isn’t exclusive to people in wheelchairs, but also those with conditions that limit movement and activity, such as people with MS.

EMS has also been used to try and speed up the rate of recovery for people who have recently had surgery. This process is called accelerated rehabilitation, and researchers have had varying results with it.

It’s important to remember that EMS isn’t exactly the same as lifting weights. Lifting weights will increase muscle mass, while EMS will only speed up muscle function in one direction. It’s more like a TENS machine.

Low Impact

The variety of exercises you can do with a TENS unit is what makes it a great option for pain management and muscle building. Although TENS is used to strengthen your muscles, it is not designed to build bulk quickly like weight lifting.

If you are goal is to build muscle, stay away from moderate-intensity TENS therapy. For building muscle, stick to high-intensity exercises and slightly less time using a TENS unit.

For moderate-intensity aerobic exercises, select the lower-voltage TENS electrodes and increase the frequency of stimulation. These lower-voltage settings allow you to stimulate muscle contraction and still have a high-intensity workout.

When you increase your endurance, you can step it up a notch and increase the voltage settings for muscle contraction. If you increase the stimulation intensity or duration of your TENS unit, you will help speed up your muscle recovery time.

High-intensity TENS workouts can be much better than high-intensity weightlifting workouts in some instances. For instance, higher intensity TENS workouts leave many of your joints, tendons, and ligaments more flexible than weightbearing exercises, which might otherwise cause issues.

By using TENS in conjunction with your weight-lifting, you’ll increase your muscle recovery time and reduce your recovery time between workouts.

Muscle Rehabilitation

While muscle rehabilitation may not sound like the most exciting thing in the world, don’t be fooled! Muscle therapy and exercise can be very beneficial and transformational when you pair the right equipment with the right knowledge.

The first step in getting started is to know what kinds of things can be done with a TENS unit. While the unit itself doesn’t do a thing to the muscle once it’s applied, the TENS unit will send electrical impulses through the muscles you are working. These impulses can increase blood flow, stimulate muscle growth, and is a great alternative for pain management.

When you are a beginner, you’ll want to stay away from the “shocks” setting. Most likely, those muscle spasms will be intense and unbearable. Not to mention, if you push too hard and over-exert yourself, you won’t be able to get the results you’re hoping for.

Muscle Atrophy

A study published in the Journal of Physiology looked at how muscle atrophy was different in people who were being treated surgically for a hernia than in people who weren’t.

The study found that in the group of people who were undergoing hernia repair, there was an increase in muscle atrophy and muscle recovery impairment. This occurred because of the decreased muscle activation in the iliopsoas muscle group.

Iliopsoas muscle groups are abdominal muscles and are crucial in the strength needed for daily activities.

An iliopsoas acting injury can occur from activities such as cycling, squatting, lifting, and any aerobic based exercise. This muscle group governs the standing position of the legs and is the prime mover when performing tasks such as overhead throwing, walking, and jumping.

When having a TENS unit applied to the area, it is believed that the inhibition of pain impulses to the spinal cord in some patients will still allow for the activation of these muscles. In addition, the applied TENS unit stimulus can also cause vasodilation which can lead to an increased blood flow to the area.

The increased blood flow can help with cellular healing. This may also help stimulate the development of new blood vessels in the muscle groups.

Pain Relief

TENS (Transcutaneous Electrical Nerve Stimulation) units can be used for pain relief. This is why they are so popular for labor pains and pain relief for those dealing with cancer. TENS units can also be used for a number of other reasons.

Muscle Stimulation

The muscle stimulation theory is that a TENS unit can be used to stimulate motor units by electrical pulses. This theory has been widely challenged.

Skeletal Muscle Contraction

Some studies have shown the possibility that TENS treatments may cause skeletal muscle contraction and may help strengthen the muscle. But currently, there is not enough evidence to prove this theory.

Muscle Confusion

Muscle confusion theory is based on the fact that TENS treatments occasionally cause the muscle to temporarily stop contracting. This can confuse the muscle into developing in a more efficient and stronger way.

Peripheral Nerve Excitation

About one-third of TENS users report the sensation of a pinch, tingling, tingle, or even pain. This has made researchers become interested in the peripheral nerve excitation theory. They believe that this may be caused by the nerves around the treatment spot becoming excited.

Muscle Tone

Vs. Muscle Strength

Although they may be lumped together in the minds of many people, muscle tone and muscle strength are distinctly different. Muscle tone is the tendency for a group of muscles to stay contracted even after the muscles are no longer receiving any signals to contract. You get muscle tone when you repeatedly contract your muscles without releasing them.

In other words, your muscles fight to stay contracted. This results in extra tension, which is why you will notice the muscles in your neck and back become tense and rigid during long periods of sitting.

As you may have guessed, muscle strength and muscle tone have very different effects on the body. Muscle tone is a good indication of muscle health but has no relationship with your body’s ability to exert force (or strength). On the other hand, muscle strength is all about your body’s ability to exert force, is influenced by muscle mass, and is related to the muscles’ ability to relax.

That being said, it’s important to understand how muscle tone relates to stressful activities, especially muscle endurance, with respect to building muscles.

Convenient and Portable

Nurse practitioners, physical therapists, and physicians commonly use TENS units for pain management and as part of radiation therapy to reduce pain and discomfort in patients. Larger units can be found on hospital and physical therapy floors.

TENS unit use is safe for use in pregnant or breastfeeding women, people with pacemakers, and diabetics. However, due to their electrical nature, pregnant women should be cautious to not expose their abdomen to the electrodes.

Note: TENS units are not approved for use by the FDA as medical devices despite excellent evidence for pain management. TENS units are not a good tool for pain control from chronic conditions, and should always be combined with professional medical advice. If you are considering using an electronic device for well-being consider purchasing a device approved by the FDA.

Treat a Range of Conditions

Transcutaneous electrical nerve stimulation, or TENS, is a relatively new form of therapy. It involves providing electrical impulses through electrodes placed at strategic points on the skin. The result is pain alleviation, muscle stimulation, relaxation, and even accelerated healing.

TENS was initially used as a form of pain relief for pregnant women, but it has since been used in people with a range of conditions, including:

  • Osteoarthritis and rheumatoid arthritis
  • Fibromyalgia
  • Carpal tunnel syndrome
  • Back pain
  • Migraines
  • Sports injuries
  • Other chronic pain

Doctors and physical therapists often recommend TENS as a treatment option.

TENS may be particularly appealing for someone who has pain associated with an injury, but it can also work for those suffering from fibromyalgia, because it may relieve pain as well as help with muscle tension.

TENS, as far as muscle building goes…the jury is still out. Many gym-goers swear by this method of “recovery,” and while there has been some research done on the efficacy of TENS during workout recovery, the results are mixed and inconclusive. Some studies show that TENS applied during bodybuilding actually inhibits muscle growth.

Pressure Sores

Pressure sores occur when the skin is continually and constantly placed under prolonged pressure without a break.

These sores are very common for caregivers of the elderly or disabled.

Symptoms of a pressure sore include:

  • Tenderness
  • Swelling
  • Redness
  • Swelling
  • Turning color
  • Hate to imagine that, but here’s the other kind of pressure sore

Are you a guy who’s trying to bulk up? You may think a TENS unit could help you pack on muscle faster, because muscles can be pumped up with electrical stimulation. But, probably not. Here’s why:

Electrical muscle stimulation (EMS) is used to repair and recover muscles, it’s used for recovery of muscles from skeletal muscle disorder and minor muscle injuries. It is used to promote muscle rehabilitation from injury and disease. And, it’s used for strength training, weight training, and cardio fitness training.

TENS stands for transcutaneous electrical nerve stimulation, a kind of electrical muscle stimulation that uses surface electrodes to apply gentle electrical stimulation across the surface of the skin. This electrical stimulation works to relieve pain and is often used during physical therapy and rehabilitation sessions.


Anytime you have a cut or an injury, your body will respond by having the injured area fill up with a clear fluid called lymph. The lymph contains white blood cells and antibodies that will help defend your body against infection.

Lymph is produced in your lymph nodes and sent to the injured areas. During the healing process, the fluid in the lymph vessels will become clear or slightly yellow.

When a wound is healing, it’s normal for there to be swelling. This is because the lymph vessels and the tissue they travel through need to stay lubricated. The fluid in the wounds attract the fluid in the nearby lymph vessels, creating the swelling.

When you have a TENS unit on a cut or injured muscle, it can sometimes look like the muscle is expanding and causing swelling even when it isn’t. This is because the TENS unit is causing the lymph nodes to stop sending fluid to the injured area. When the lymph nodes stop draining the fluid, it will start to pool and swell.

Using a TENS unit can help swelling go down when it’s happening, but it’s only temporary. Once you turn the unit off, the lymph nodes will start pumping the fluid again and the swelling will come back.

A focus on ab belts

Which claim to produce copies of the same results you’d get from ab machines or ab rolls, but people still have questions.

Let’s start with one of the most common: How are ab belts supposed to work? Many of these rely on muscle contraction through nerve stimulation, and many consumers are under the impression that it’s essentially like a TENS unit that provides a steady baseline of stimulation (causing the muscles to contract) as you go about your normal day. That’s not quite how it works, though.

The verdict: Can a TENS unit build muscle?

A professional TENS unit can only be used to relax muscles. This means that the muscle can actually get weaker. Don’t get me wrong, muscle relaxation is a good thing but the point here is that you’re wasting your time if you’re looking for a TENS unit to build muscles.

Due to the design of the TENS unit, it can only do two things: stimulate electrically or block electrically. When you stimulate electrically, it is going to cause the muscles that the electrodes are attached to to contract. Basically, when you stimulate, that muscle should be flexing. By blocking an electric signal (or current), it tells the muscle to relax.

The muscles do not have any respect for the type of current. That is why you can’t make them contract with the electrical stimulation, but you can make them contract with a direct muscle stimulation.

Most of the time, people who look for ways how to make their TNS unit work for muscle building, are trying to make the muscles move with the TNS unit.