Microelectric Currents

I once had small electric currents passed through acupuncture needles that were put in my back to relieve pain.  The therapist explained that the currents were pulsing my muscles many times over the twenty minutes that the needles were in.  That pulsing of the muscle made them tired and so they would relax.

Here is an article about many medical uses of small electric currents from healing wounds to pain relief to cosmetic uses in making skin firmer.