Boost Your Gains: A Practical Guide to EMS for Muscle Growth

By MaryAnn DePietro CRT

Electrical muscle stimulation (EMS) involves delivering electrical impulses to the muscles through electrodes placed on the skin. EMS is used as a muscle stimulator for muscle growth.


Other forms of electrical stimulation include transcutaneous electrical nerve stimulation. (TENS). The key difference between TENS and EMS is that TENS is primarily used for pain relief, achieving this by stimulating nerve endings. EMS for muscle growth occurs due to muscle stimulation and subsequent muscle contractions.


EMS muscle building is a complementary tool that can enhance workouts, improve recovery, and target specific muscle groups.


This article acts as a guide to EMS for muscle growth. It includes the science behind how it works, how to incorporate it into a muscle-building routine, and more.

What is Electrical Muscle Stimulation (EMS)?

Electrical muscle stimulation, also known as neuromuscular electrical stimulation (NEMS), involves delivering intermittent electrical stimulation through surface electrodes placed on the skin. The electrical impulses activate motor nerves and muscle fibers. Stimulation causes an involuntary muscle contraction.


Electrical stimulation replicates the natural signal sent by your brain to your muscle, leading to voluntary muscle contraction. The individual consciously controls this voluntary contraction. However, with EMS, the contraction is initiated by the EMS device as opposed to natural nerve signals. This causes involuntary muscle contractions.


EMS has been used for decades in sports science and rehabilitation. The initial use dates back to the 1960s. However, technological advances in the late 1980s and early 1990s improved technology. These developments increased the therapeutic use of EMS and rehabilitation.


EMS gained traction in the last two decades and is widely used by:

Does EMS Really Build Muscle? Evidence and Mechanisms

Researchers have addressed the question, "Does EMS build muscle?" The answer appears to be yes. EMS can really build muscle.


Scientific evidence and studies support the use of electrical muscle stimulation to increase muscle mass and improve function. For example, a study in the Journal of Cachexia, Sarcopenia and Muscle found that electrical muscle stimulation can help. It can:


  • Increase muscle mass by about 1%

  • And improve muscle function by 10-15% after 5 to 6 weeks of treatment.


Another study in the journal Sensors compared the effects of strength training alone with those of strength training combined with EMS on muscle strength.


The study involved 25 male badminton players with professional training experience. Participants had baseline measurements of jump tests, including a jump smash and a squat jump. Half of the participants were assigned to a strength conditioning program, while the other half were assigned to a strength training program with added EMS. Muscle activation and strength were measured using electromyography immediately after consuming drinks, exercising, undergoing EMS, and participating in strength conditioning.


The results showed that EMS and strength training significantly improved performance. This was true for both the static squat jump and the jump smash. These improvements were superior to both the baseline and the strength-only group. Researchers theorize that EMS improved muscle recruitment, specifically activation of fast-twitch muscle fibers.


EMS causes various physiological changes that promote muscle growth. For example, EMS may stimulate the regeneration of satellite cells.

Satellite cells are a type of muscle stem cell that is located within the muscle tissue. These cells may be inactive in adult muscle tissue. Stimulating these satellite cells can potentially increase muscle mass and strength.


Additional mechanisms leading to EMS muscle building include:


  • Activation of fast-twitch muscle fibers (often harder to engage voluntarily).

  • Increased muscle fiber recruitment.

  • Improved anabolic/catabolic balance

  • Stimulation of satellite cell regeneration

  • Potential for higher intensity contractions than voluntary effort alone


EMS for muscle growth has the potential to increase muscle mass and strength, which may have a direct effect on athletic performance.

A meta-analysis in the Journal of Strength and Conditioning Research examined the effect of EMS on athletic performance. The review included 89 published trials.  


The analyzed studies involved different types of EMS treatment, including various time durations and currents. Most studies used a biphasic waveform, and EMS was applied to the legs.


Results indicated that strength, power, and speed improved after 3 to 6 weeks of stimulation. For instance, the squat jump improved by 21%, and the vertical jump height improved by 25%.

Benefits of Incorporating EMS into Your Muscle Building Routine

Incorporating EMS for muscle growth into your routine can have several potential benefits, as listed below.


Enhanced Muscle Activation & Recruitment

EMS can effectively promote skeletal muscle protein synthesis. It also targets deeper muscle fibers that may be challenging to engage in and underutilized in traditional exercises alone.


Time Efficiency

EMS may provide shorter, intense workouts that help improve muscle strength and mass. For example, 20-minute sessions may be comparable to longer traditional works. A 2023 systematic review and meta-analysis published in Medicine found that EMS training has a positive effect on muscle mass, strength, body fat, and power. The average duration of training in many studies was 20 minutes.


Joint-Friendly Training

EMS does not place the same stress on joints as heavy lifting. This might make it ideal for individuals during a rehabilitation program or those with joint problems.


Improved Recovery

EMS can improve blood flow, reduce lactic acid buildup, and subsequently decrease delayed muscle soreness. Improving blood flow can promote tissue recovery. Overall, enhanced circulation can also improve cardiovascular health.


Targeted Muscle Engagement

By placing electrodes in specific areas, users can precisely target the specific muscle group or imbalances they're trying to strengthen.


Complementary to Traditional Training

EMS can enhance results when used in conjunction with conventional exercises. EMS may engage a higher percentage of muscle fibers when compared to voluntary exercise alone. This increase in muscle fiber recruitment can amplify the results of conventional exercise.


However, it's crucial to remember that EMS is a complementary tool. It is not meant to be a complete replacement for all aspects of traditional exercise and training.


Prevention of Muscle Atrophy

Stimulating muscle contraction involuntarily may be beneficial for individuals who are immobilized due to injuries or illnesses, thereby preventing muscle atrophy. EMS may also be a helpful tool for individuals with sarcopenia, especially in combating early muscle loss.

EMS vs. Traditional Strength Training: A Comparative Analysis

Although EMS may complement traditional strength training, it's essential to understand the similarities and key differences.


Similarities

The main similarity between EMS and traditional strength training is that they both aim to:

  • Stimulate muscle contraction

  • Promote growth

  • And enhance strength.


Key Differences

There are also several key differences between the two, such as the following:


  • Voluntary Control vs. Electrical Impulse: In traditional strength training, muscle contraction is initiated in the brain, not by an electrical impulse. With EMS, the device causes the contraction.

  • Progressive Overload: In strength training, progressive overload involves increasing the weight, repetitions, or sets. With EMS, progressive overload is achieved by increasing the frequency or intensity of the device settings.

  • Functional Strength & Skill Development: Traditional training is often superior for performing complex movement patterns and coordination.

  • Whole-Body Benefits: Traditional exercise offers broader cardiovascular, cognitive, and skeletal benefits that EMS alone may not.

  • Synergistic Approach: In many cases, combining traditional strength training with EMS yields the best outcomes.


Multiple studies suggest that superimposing EMS on voluntary muscle contraction shows greater strength gains than exercise alone. For instance, a study published in the Journal of Sports Science and Medicine divided 20 athletes into two groups. One group performed a six-week squat program, while the other group performed the same exercises with EMS applied. Results indicated that the EMS group had greater strength improvements compared to those who exercised alone.


EMS is not a magic bullet to improve strength. However, it can be an effective tool when used in combination with traditional strength training to enhance gains.

How to Effectively Use an EMS Unit for Muscle Building

Understanding how to use EMS for muscle building effectively is vital to achieving optimal results. Consider the points below.


Choosing the Right EMS Device

It is critical to choose the correct device. Look for devices that offer both TENS and EMS modes, such as TENS 7000. Review the range of settings available, such as intensity, pulse width, and frequency options.


Selecting a device that has FDA clearance or approval ensures it has met rigorous standards for safety and efficiency.


Pad Placement Guide for Muscle Growth

Placing the electrodes properly is critical when using an EMS unit for muscle building. General principles to keep in mind include:

  • Place the electrodes around the muscle belly, avoiding direct placement over the bone.

  • Ensure the skin is clean to allow the electrodes to adhere correctly.

  • Using gel pads will allow for good conductivity.


For specific diagrams on electrode placement, refer to the device's manuals or our guide on how to use a muscle stimulator.


Optimal EMS Settings for Muscle Hypertrophy

The specific settings for muscle hypertrophy may depend on the individual circumstances. Some general recommendations include those listed below.


Frequency (Hz)

Typically, a frequency of 50-100 Hz is used for muscle growth. Research in the Journal of Cachexia, Sarcopenia, and Muscle found that users responded with increased muscle mass after exposure to a 50-100 Hz frequency.


Pulse Width (µs)

A pulse width of 300-450 is also recommended.


Intensity

Choose an intensity as high as individually tolerated for strong, visible contractions without pain.


Duration & Sessions

The usual session time is 2-30 minutes, with a frequency of 2-3 times per week. Start slower if needed.


Integration with Workouts

There are a few ways to integrate EMS with their workouts, such as:


  • Using EMS pre-workout for muscle activation

  • EMS during voluntary muscle contraction

  • EMS post-workout for recovery and delayed muscle soreness


Progression

Always gradually increase the intensity and duration of EMS use by doing the following:


  • Do not increase the intensity significantly during a single session. Instead, gradually increase the intensity over a few sessions.

  • Gradually increase the duration of your session, 20 to 30 minutes, as tolerated.

  • Slowly increase your frequency. For example, start with one session a week and gradually increase to two to three sessions per week.

  • Listen to your body. If anything feels uncomfortable, stop the treatment session immediately.


It's always important to read your device manual and consult a healthcare professional before starting EMS therapy.

Can a TENS Unit Build Muscle? Understanding the Differences

It's essential to understand the difference between TENS electrical stimulation and EMS. For instance, can a TENS unit build muscle?


TENS therapy is not designed to build muscle. Instead, its primary purpose is pain relief. This is achieved through the gate control theory and the release of endorphins.


The gate control theory says that stimulating non-painful nerve fibers can lower pain signals sent to the brain. TENS also promotes the release of endorphins, neurotransmitters that act as natural painkillers in the body.


EMS stimulates muscle contraction, re-educates, strengthens, and grows muscle mass.


TENS and EMS utilize different waveforms and frequencies. The current used in TENS is usually a lower intensity, targeting superficial nerves.


TENS also utilizes different pulse widths that do not induce strong muscle contractions, which are necessary for hypertrophy.


TENS therapy stimulates nerves for pain relief while EMS stimulates muscle fibers for contraction and strengthening.

Conclusion: Empowering Your Muscle Growth Journey with EMS

EMS causes involuntary muscle contraction through electrodes placed on the skin. This induced muscle contraction can promote muscle growth. It can be an effective complementary tool for strength training. It can also be used in rehabilitation to prevent muscle atrophy.


EMS should not be confused with TENS therapy. Both types of devices use electrical stimulation. However, TENS targets superficial nerves to relieve pain, rather than building muscle.


To use EMS safely, following the device's manual for proper use is crucial. It is also best to consult a healthcare professional to ensure EMS is right for you.


EMS can be a valuable, science-backed tool for muscle growth when used correctly as part of an overall fitness strategy.

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About the Author

MaryAnn DePietro CRT is a licensed respiratory therapist with over 15 years of clinical experience in critical care, emergency medicine, and pulmonary rehabilitation. She is also an American Council on Exercise certified personal trainer and holds specialty certifications in orthopedics, senior fitness, and weight management. MaryAnn has a degree in Rehabilitation from Penn State University and a degree in respiratory therapy.


In addition to her clinical experience, she has written extensively about all things medical, as well as health, fitness, and aging for various websites, magazines, and newspapers.

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