What is Electrical Muscle Stimulation? A Complete Guide

Electrical muscle stimulation involves using a special device to deliver electrical impulses through the skin to the muscles. The electrical impulse causes the muscle to contract, potentially having strengthening effects and other benefits.

The technology and devices used to deliver electrical muscle stimulation have continued to evolve. EMS has become a form of treatment used by various medical professionals, including sports medicine physicians and physical therapists.

Learning more about electrical muscle stimulation is helpful before determining if it is right for you.

The article below provides a guide to electrical muscle stimulation and answers common questions about EMS.

II. The Science Behind Muscle Stimulators

The first question someone may have about e-stim technology is, "What is a muscle stimulator?"

E-stim is a broad term that includes two forms of electrical muscle stimulation:

• Electrical muscle stimulation (EMS) involves using electrical impulses to stimulate muscle contraction and strengthen the muscles.

• Transcutaneous electrical nerve stimulation (TENS) reduces pain instead of stimulating muscle contraction.

Electrical muscle stimulation (EMS) uses a special device to deliver electrical impulses to the muscles through electrodes placed on the skin. This electrical impulse leads to an involuntary muscle contraction.

The device delivers electrical stimulation to the motor nerves. The impulse recruits more muscle fibers or stimulates contractile force in the muscle to enhance muscle contraction. The electrical impulse from an EMS machine mimics the signals sent from your brain to your motor nerves, which leads to muscle contraction.

Users and practitioners can adjust the machine to alter the intensity of the muscle contraction. Depending on the goal of treatment and the individual, it can range from forceful to gentle.

EMS forces the entire muscle to activate, recruiting deeper muscles that may not typically become recruited during conventional exercise.

Your body has different types of muscle fibers, including slow-twitch and fast-twitch. Slow-twitch muscle fibers become active first during conventional exercise. Meanwhile, fast-twitch muscle fibers are more difficult to activate with exercise.

However, it's essential to strengthen these muscle fibers. They are used in powerful movements and can help improve athletic performance. EMS activates fast twitch muscle fibers, which is beneficial for muscle strengthening.

Muscle contraction

To understand what electrical muscle stimulation does, learning the basics about the muscle contraction process is helpful.

To move a muscle, the motor neuron sends an electrical signal called an action potential to the neuromuscular junction.

The neuromuscular junction is a synapse where the motor neuron connects and sends electrical signals to the muscle fibers.

These electrical signals initiate a muscle contraction. The principle behind electrical muscle stimulation is it mimics the action potential that originates from the central nervous system.

Does Electrical Muscle Stimulation Build Muscle?

EMS has different uses, including muscle recovery as part of physical therapy. But does electrical muscle stimulation build muscle? Research indicates that it has the potential to do so.

EMS has the potential to increase both muscle strength and hypertrophy. Muscle strength focuses on increasing the force a muscle can generate, while hypertrophy involves increasing muscle size.

An editorial in the Journal of Cachexia, Sarcopenia, and Muscle says that studies show EMS can help. In both studies of experimental models and humans, EMS can increase muscle mass by about 1%. It can also boost muscle strength by 10 to 15% after 5 to 6 weeks of treatment.

A study published in the journal Critical Care Research and Practice examined using electrical muscle stimulation for hospitalized patients. The research involved 142 patients randomly assigned to either the electrical muscle stimulation or the control group. Researchers evaluated muscle strength before EMS sessions in both groups.

Participants in the EMS group had 55-minute sessions with electrical muscle stimulation applied daily to the following:

• Vastus lateralis

• Vastus medialis

• And peroneus longus of both legs during their hospital stay.

Muscle strength was re-evaluated before discharge. Researchers found that EMS preserved or enhanced the strength of critically ill patients. The study's results implied that EMS had a beneficial effect in improving strength in the muscle groups stimulated.

Another study published in the International Journal of Environmental Research and Public Health examined the effect of electrical muscle stimulation on healthy adults. The study compared the effects of electrical muscle stimulation and strength training on elbow flexor muscle thickness. 

The study involved 40 participants randomly divided into three groups that received:

• The strength training protocol

• The EMS protocol

• Or a combination of both. 

There was also a control group. 

The electrical muscle stimulation group received EMS 24 minutes a week, twice a week, for 8 weeks. The strength training group did three bicep exercises. They completed three sets of 12 repetitions with gradual overload twice a week for eight weeks.

Study results indicated that groups participating in strength training, electrical muscle stimulation, or a combination of both significantly improved elbow flexor muscle thickness. The research concludes that EMS can help induce muscle growth and strength, similar to strength training.

III. Benefits and Applications of Electronic Muscle Stimulation

The benefits of electronic muscle stimulation may include the following:

Muscle Recovery and Rehabilitation

EMS increases blood flow to an injured area, which can help with muscle healing and recovery. By stimulating muscle contractions, EMS may help repair, strengthen, and re-educate atrophied or weakened muscles. It may be an effective part of a rehabilitation program.

Pain Management

EMS can stimulate the release of endorphins, which block pain signals from reaching the brain. It may also decrease the pain associated with muscle spasms. EMS may also complement TENS treatment, which focuses on reducing pain.

Muscle Strengthening and Conditioning

As the research states above, EMS may strengthen and condition muscles after an injury. It also helps enhance strength gains in a fitness program.

Enhancing Sports Performance

In addition to strength training, EMS may help activate additional muscle fibers, improving strength and enhancing sports performance.

Assisting with Rehabilitation

EMS can also aid a rehabilitation program. This may be helpful after procedures such as knee surgery. Always follow your doctor's or physical therapist's recommendations for EMS use.

IV. How to Use an EMS Muscle Stimulator

Below is general information on how to use an EMS muscle stimulator.

Step-by-Step Instructions

1. Prep the skin: The area where you'll place the electrodes should be clean and free of lotions, oils, and hair.

2. Selecting electrodes: Select an electrode that is the right size and shape for your target muscle. Make sure it is sticky enough to adhere to your skin.

3. Connect the wires: Plug the wires from the stimulator into the electrode pads.

4. Turn the EMS machine on: Once the electrodes are placed and the wires are attached to the electrode pads, turn the device on.

5. Adjust the settings: Some machines may allow you to choose a specific mode or program, such as muscle strengthening or pain relief. Adjust the intensity of the machine. Start slowly and gradually increase the intensity.

Specific devices may also let you adjust the pulse rate and pulse duration. Additionally, set the timer for the duration of your treatment.

Electrode Placement for Different Muscle Groups

Electric electrode placement is critical for getting the best treatment. Determine the specific muscle you want to strengthen.

Typically, You'll place one electrode in the middle of the fleshy part of the muscle called the muscle belly. Place the second electrode on the opposite end of the muscle, trying to keep the electrodes about 3 cm apart. Avoid placing electrodes on bone or tendons.

Examples of electrode placement for various muscle groups include:

• Quadriceps: Consider placing an electrode on the vastus medialis and vastus lateralis for quadriceps pain.

• Biceps: Place one electrode on the middle of the bicep muscle and the second one closer to the shoulder.

• Hamstrings: Electrode placement can include one on the bicep femoris and one closer to the back of the knee.

How Long Should You Use Electrical Muscle Stimulation?

It's essential to understand how long you should use electrical muscle stimulation. The duration of treatment may depend on the goal, such as whether you're using it for pain relief or strength benefits.

General guidelines include a treatment time between 20 and 30 minutes. However, following a manufacturer's instructions is critical for optimal treatment with the fewest side effects.

You can also speak to your doctor regarding specific recommendations for treatment times. It's also essential to listen to your body. If you feel pain or discomfort, decrease the intensity or stop the treatment.

V. Safety and Considerations

It's vital to use EMS safely to prevent adverse effects. While EMS tends to be safe, it may not be appropriate for everyone in every instance. Contraindications to electrical muscle stimulation include the conditions and situations below:

• In individuals with a pacemaker

• Pregnancy

• Epilepsy

• Peripheral vascular disease

• Individuals with arrhythmias

Additionally, precautions to take include:

• Do not place any EMS device over an area of active infection or broken skin.

• Do not use on areas of the body that have severe osteoporosis.

• Do not exceed the manufacturer's recommendation for intensity.

It's vital to consult with a healthcare professional before using EMS to determine if it's appropriate for you. A healthcare professional can also provide instruction on the intensity and duration of treatment for your condition.

Potential Side Effects and Precautions

EMS is generally safe. However, potential side effects can occur and may include:

• Skin irritation: This is the most common side effect related to EMS. It may include redness and itching at the site of electrode placement.

• Headache and dizziness: Some individuals may experience headaches or dizziness after using EMS.

• Muscle damage: EMS can possibly induce muscle damage. However, this is uncommon and is more likely to occur when used at high intensity or for prolonged sessions.

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Following the manufacturer's recommendations, such as the recommended time and intensity, can reduce the likelihood of side effects.

Frequently Asked Questions

Does electrical muscle stimulation replace strength training?

Electrical muscle stimulation does not replace strength training. It can be an effective tool for enhancing sports performance but should not substitute strength training.

Do muscle stimulators work to burn fat?

Muscle stimulators do not typically burn fat. They may help improve muscle tightness but are not considered a weight loss tool.

Is EMS e-stim safe?

EMS is generally safe. However, people with certain medical conditions should avoid using EMS. It's also important to follow your healthcare provider's recommendations.