Transcutaneous Electrical Nerve Stimulation (TENS) vs Electrical Muscle Stimulation (EMS)

What is Transcutaneous Electrical Nerve Stimulation (TENS)?

Nerve stimulation is a technique that aims to relieve pain using an electrical current. Transcutaneous Electrical Nerve Stimulation (or TENS) involves sending small, low-voltage electrical impulses to a specific nerve via electrodes placed on the skin, with the aim of modifying the way that neurones send signals and preventing the pain signals from reaching the brain.

What is Electrical Muscle Stimulation (EMS)?

Electrical stimulation is a technique that aims to stimulate the muscles using an electrical current in order to achieve a specific result. Electrical Muscle Stimulation (EMS) involves delivering small, low-voltage electrical impulses to a muscle via electrodes placed on the skin, in order to cause the muscle to contract. This muscle contraction can have two, very different purposes: firstly, to relieve inflammation, and secondly, to strengthen the muscle without involving the nervous system, which avoids pain and fatigue.

How EMS and TENS machines work

A TENS machine, also known as a TENS unit or a nerve stimulator, consists of an electrical impulse generator connected to electrodes placed on your skin. It works by delivering small electrical impulses to stimulate the mechanisms that cause pain. TENS machines work in three different ways:

• They block the transmission of pain signals to the brain.
• They stimulate the production of endorphins (which are natural painkillers).
• They improve blood circulation.

An EMS machine works in more or less the same way. It also consists of an electrical impulse generator connected to electrodes that are placed on your skin around the muscle to be treated. It also works by sending small electrical impulses, which this time are delivered directly to the muscle, causing it to contract. The muscle contracts and relaxes repeatedly, which helps to improve blood circulation, which in turn serves to:

• Relax the muscle
• Minimize any inflammation
• Prevent muscle atrophy
• Speed up muscle healing
• Stimulate muscle growth

EMS or TENS machines: which to choose?

TENS machines are used to relieve nerve, muscle or joint pain, which is often chronic and takes various forms, including inflammatory arthritis, back pain, foot pain, contractions during childbirth, or post-operative pain. Migraine pain can be relieved by specialized TENS machines.

EMS machines, on the other hand, are used to relax or strengthen the muscles, for example in cases of muscular spasm, poor blood circulation (particularly in the back and nape of the neck), muscle atrophy after an illness or as part of rehabilitation from an injury. They are therefore more often recommended for the relief of muscle pain. Athletes also sometimes use EMS in order to recover from an injury more quickly, as electrical muscle stimulation will enable them to (re)build muscle without too much strain and to exercise muscles that they may not use very much.

The main difference

Transcutaneous Electrical Nerve Stimulation (TENS) machines stimulate the nerves exclusively for the purpose of relieving pain, whereas Electrical Muscle Stimulation (EMS) machines are designed to stimulate the muscles for the purposes of strengthening and rehabilitating them.

We therefore recommend that if you are seeking to relieve nerve pain, you use a Transcutaneous Electrical Stimulation (TENS) machine that combines TENS with heat, such as OMRON HeatTens. Similarly, if you are seeking rehabilitation from muscle pain, or to strengthen your muscles as part of a training programme, for example, we would advise you to choose an Electrical Muscle Stimulation (EMS) machine.