Transcutaneous electrical nerve stimulation (TENS) is a form of electrotherapy and a method of pain relief involving the use of a mild electrical current. The electrical impulses help reduce the pain signals going to the  spinal cord and brain by temporarily ‘switching off’ the nerve endings of the affected area, thus helping to relieve pain     and relax muscles. These impulses also stimulate the production of endorphins, which are the body’s natural painkillers.

The electrotherapy technique makes it possible to cause the passage of electric currents through the body, normally intended to excite and contract a muscle. By activating the muscle through stimulation, electrotherapy quickly recovers muscle tone allowing a return to the anti-resistance activities with which the muscle can recover trophism.

Through muscle contraction, electrotherapy also squeezes the venous blood towards the heart, draining liquids that, in the absence of activity, ‘stagnate’ further and feed the suffering of the tissues affected by trauma. Muscle pump activity induced by electrostimulated contraction will reduce the effects of edemas from venous and lymphatic stasis — linked to trauma and immobilisation — to promote the recovery of injured limbs.

One of the difficulties facing the validation of TENS is the limitations of a placebo group within trials.  This is because during the application of TENS, it is accompanied by an easily observed ‘sensation’ as the current is felt passing through. The synergistic effects of ultrasound and TENS therapies together have also been noted, although further research into this area is required.

Further reading