Electrical Muscle Stimulation: Enhance Fitness & Recovery

Electrical muscle stimulation (also called EMS, E-stim, or electrotherapy) is a physical therapy procedure. It involves sending an electrical impulse through the skin to target specific muscles and nerves and trigger a muscle contraction. 

How EMS Works: Involuntary Muscle Contractions  

The muscle contraction triggered by EMS is an involuntary muscle contraction. This is in contrast to a voluntary muscle contraction that is initiated through conscious thought, such as when you move your arm or engage in physical exercise. 

Research in applied physiology and human kinetics has shown that involuntary contraction of muscle fibers and nerve fibers through EMS therapy can help to improve muscle strength, enhance muscle function, reduce swelling, provide pain relief, and speed up wound healing.

Types and Variations of EMS

The different types of EMS involve basically the same thing, namely, applying an electrical impulse to a part of the body to increase nerve and muscle activity. However, EMS is called by different names based on how the electrical current is applied, the part of the body being treated, or the underlying reason for the treatment.

Electrical Muscle Stimulation (EMS)

EMS involves the use of low-frequency electrical waves. It is mainly used to enhance athletic performance.

Russian Electrical Stimulation

Russian electrical stimulation, also called functional electrical stimulation, uses high-frequency electrical current and is also used in athletic training, similar to EMS.

Transcutaneous Electrical Nerve Stimulation (TENS)

Transcutaneous electrical nerve stimulation (TENS) uses a mild electrical current to provide pain relief. TENS units are small battery-operated devices that have electrodes (sticky pads) connected to leads. TENS is similar to electrical muscle stimulation (EMS), but EMS makes muscles contract more strongly and is therefore used for athletic training purposes.

Neuromuscular Electrical Stimulation (NMES)

Neuromuscular electrical stimulation uses a similar electrical current as TENS, but it is mainly used to retrain muscles after injuries or periods of disuse. This physical therapy treatment can help to increase muscle strength and range of motion in people recovering from injuries or after periods of immobilization. Learn why muscles get sore.

Spinal Cord Stimulation

Spinal cord stimulation is a more invasive treatment that is used to manage chronic pain. A small pacemaker-like device (generator) is placed in the buttock or abdominal muscles, and thin wires (electrodes) are placed between the vertebrae and spinal cord. Patients can use a remote control to send electrical impulses to the spinal cord when they experience pain, causing an interruption to the nerve impulses that carry the sensation of pain.

Uses of EMS: What Does Electrical Stimulation of Muscles Do?  

Applications in Fitness and Athletic Training

Electrical muscle stimulation (EMS) is used for a variety of athletic purposes, including:

• Strength training: EMS can help athletes build muscle strength and power, increase muscle size, and improve endurance. 

• Muscle conditioning: E-stim electrostimulation exercise can also be used for muscle conditioning by targeting specific muscle fibers. This can allow athletes to train weak or injured muscles and improve muscle function. For instance, someone in a competitive sport, such as marathon runners, may use electrical muscle stimulation to train their leg muscles to resist fatigue.

• Muscle recovery and pain management: EMS can help with muscle rehabilitation and pain relief and accelerate recovery in athletes with muscle injuries. 

Therapeutic Uses in Physical Medicine and Rehabilitation  

A physical therapist can place electrodes on specific areas of the skin and recruit targeted muscles during electrical muscle stimulation (EMS) treatments. EMS can be used for a range of purposes in clinical practice, including:

• Stimulating muscles to prevent muscle atrophy (wasting and thinning), for example, in people who are immobilized due to fractures and cannot do physical exercise. 

• Strengthening weakened or injured muscles by causing repeated contractions to simulate physical training. 

• Maintaining muscle tone in a target muscle, for example, after a stroke. 

• Re-training muscles and improving functional movement with muscle re-education after injuries and illnesses.

• Improving range of motion and flexibility by stimulating motor nerves.

• Relaxing muscle spasms to reduce pain.

• Reducing swelling by improving circulation and reducing water retention. 

• Relieving pain by blocking the transmission of pain impulses from the body to the brain. 

• Healing wounds by increasing blood flow to the area. 

• Treating urinary incontinence with EMS training of pelvic floor muscles.

• Aiding neurorehabilitation in patients with spinal cord injuries through voluntary motor training to improve motor function.

• Employing neuromuscular electrostimulation (NMES) for pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD). 

EMS for General Health and Wellness and Cosmetic Enhancement

Electrical muscle stimulation (EMS) is also used in cosmetic treatment sessions in healthy subjects. The stimulation parameters (pulse duration and frequency) are typically lower than what are used during therapeutic uses of EMS. Mild electrical currents are used to tone and tighten skin and slim and tone areas such as the abdomen, arms, and thighs. These EMS treatments are usually performed using hand-held devices. 

Benefits of EMS  

Muscle Strengthening and Conditioning  

Electromyostimulation training can lead to strength gains by mimicking voluntary contractions and muscle movement. In other words, EMS treatments can have similar effects as a voluntary exercise program by triggering repeated muscle contractions.

Muscle Recovery  

Electrical stimulation causes involuntary contractions in affected muscles, which promotes recovery in injured muscles. This is accomplished by re-educating muscles, helping to fight atrophy (thinning and wasting of muscle fibers) through motor unit recruitment, increasing blood flow to an injured muscle, and improving overall muscle function and motor control.

Pain Reduction 

Electrical impulses can decrease the transmission of pain signals from parts of the body to the brain, thus providing pain relief. 

Do Electronic Muscle Stimulators Really Work?   

Athletic Performance

Clinical studies have shown that electrical stimulation of muscles and nerves has benefits for both athletes and non-athletes.

One study found that trained and elite athletes who used EMS for 3-6 weeks had significant improvements in strength, speed, power, and jumping ability.

Another study showed that superimposing EMS on strength training in healthy non-athletic adults leads to improvements in contracted muscle size and more efficient muscle contractions. 

Recovery from Injuries and Surgeries

Russian stimulation or functional electrical stimulation has been found to cause a statistically significant improvement in the ability to generate muscle force in people with muscle weakness from athletic injuries as well as those who have undergone ACL repair (anterior cruciate ligament surgery).

Pain Management

A systematic review and meta-analysis of randomized clinical trials showed that transcutaneous electrical nerve stimulation (TENS) results in decreased pain during and after treatment. Similar to exercise and voluntary contraction of muscles, nerve and muscle stimulation also causes the release of endorphins (happiness chemicals). 

Potential Side Effects and Considerations

What Are The Side Effects of Electrical Muscle Stimulation?

EMS is largely safe when performed by trained healthcare professionals. However, there is a risk of skin irritation, tissue burns, bruising, pain, and electrical shocks. 

Contraindications and Cautions  

The following people should avoid EMS or use it with caution under the supervision of a healthcare provider:

• Pregnant women

• People with epilepsy

• Those with implanted pacemakers and other implanted medical devices

• Those with transdermal drug delivery systems (medicine skin patches)

• People with open wounds or certain skin conditions

Safety Guidelines for Using EMS Devices

Most FDA-approved electrical muscle stimulators (EMS devices) are intended for use by healthcare providers in physical therapy or PM&R (physical medicine and rehabilitation) clinics. However, there are some devices available to use at home. The U.S. Food and Drug Administration warns that:

An EMS device may temporarily strengthen and tone a muscle, but no device is FDA-approved for weight loss, reduction in waist size, or building strong abdominal muscles.

Choose EMS devices manufactured by reputable companies to ensure they are properly designed and comply with electrical safety standards. Follow the instructions carefully to prevent electrocution and other serious adverse events.