Abdominal electrical muscle stimulation makes the stomach muscles contract using weak electrical pulses sent through electrodes stuck to the skin. It can work these muscles. It doesn't make you lose weight and doesn't replace physical activity.
Here's how it works, what the available data show, how to use it carefully and when to ask for medical advice before you start.
What is electrical stimulation?
Several devices use electrodes placed on the skin, but not for the same purpose:
- Electrical muscle stimulation (EMS, or NMES in medical terms) sends pulses that make the muscles under the electrodes contract. This is the principle behind abdominal stimulators.
- TENS (transcutaneous electrical nerve stimulation) is mainly used to ease some types of pain, by acting on the nerves. Its purpose is not to work the muscle.
Most electrical stimulation devices reviewed by the U.S. Food and Drug Administration (FDA) are intended for physical therapy and rehabilitation, under the supervision of a healthcare professional. Consumer devices use the same principle. This article is about electrical muscle stimulation.
What happens when the electrodes stimulate a muscle?
The current triggers contractions without you having to move. These contractions are not identical to those of a voluntary movement: during normal effort, the nervous system gradually recruits the motor units it needs; with electrical stimulation, it's always the same ones, located under the electrodes, that contract at the same time.
Researchers believe this recruitment pattern partly explains why an electrically stimulated muscle tires more quickly than during voluntary effort. It's also why the intensity and length of sessions matter.
Abdominal EMS: what it can and cannot do
According to the FDA, an electrical stimulation device may temporarily strengthen a muscle. The agency states that no device has been cleared to date for weight loss, waist reduction or getting "rock-hard" abs, and that, used on its own, a device will not give you a "six-pack".
A study published in 2005 compared 24 adults who used an abdominal stimulator (5 days a week, 20 to 40 minutes per session, for 8 weeks, with no other exercise) with 16 adults who didn't change their habits:
- abdominal muscle strength and endurance increased in the stimulated group;
- weight, body mass index and skinfold thickness (an indicator of fat under the skin) did not change significantly;
- waist circumference decreased by an average of 3.5 cm, and participants felt there had been a change in their stomach area.
This is a single, older study, carried out on few people and with a single device. It describes local muscle work: it does not show fat loss and cannot be used to promise a result with another device.
In short, abdominal electrical muscle stimulation:
- does not make you lose fat or weight on its own;
- does not reshape your figure and does not define your abs;
- is not a treatment: a consumer device is not designed to treat pain or a health problem.
Electrical muscle stimulation and physical activity
Electrical muscle stimulation does not replace physical activity. A stimulator can accompany a strengthening routine, as an extra: it makes one muscle contract locally, whereas physical activity engages the whole body, the heart and breathing. The FDA also points out that a noticeable change in appearance comes from a suitable diet and regular exercise, not from a device alone.
How do you use an electrical muscle stimulation device?
- Read the user manual in full: session length, intensity, electrode placement and contraindications are specific to each device. The FDA stresses this point.
- Place the electrodes on clean, dry, healthy skin, where the user manual indicates.
- Start at the lowest intensity and increase gradually. You should feel the contraction, without pain.
- Stick to the stated duration and don't extend it.
- Stop if your skin turns red, itches, feels hot or hurts, and remove the electrodes.
As with TENS devices, don't use it while sleeping, in the bath or shower, or while driving or operating machinery.
Precautions and contraindications
The FDA has received reports of electric shocks, burns, bruising, skin irritation and pain, some of which required hospital care. It also reports cases of interference with implanted devices such as pacemakers and defibrillators, and notes that cables on non-compliant devices can expose users to electric shock.
Do not use an electrical muscle stimulation device without medical advice:
- if you have a pacemaker, a defibrillator or another implanted electronic device;
- if you are pregnant;
- if you have epilepsy;
- if you have a known health condition, recent surgery or an injury in the abdominal area, or pain whose cause you don't know.
Never place electrodes on irritated, damaged, infected or numb skin, or on the neck or face. For pregnancy, epilepsy, the skin and the neck, these instructions are the ones the UK's National Health Service (NHS) gives for TENS; they are included here as a precaution, because both techniques pass a current through electrodes stuck to the skin.
What about Komua 03?
Komua 03 is an electrical muscle stimulation device: one pad for the abdomen and two smaller additional pads, each with its own control unit with a display, rechargeable via USB. Intensity and mode are set on the control unit. It's used at home, alongside physical activity, and promises no effect on weight or figure.
The precautions above apply, and the product's user manual is the reference for its use. To find out more, see the Komua 03 · Abdominal Muscle Stimulator product page. To compare it with other types of devices, see our guide How to choose a massage device.
