Electrotherapy
Mid-frequency electrotherapy
"Mid-frequency electrotherapy means treatment between 1,000 and 100,000 Hz in frequency.Besides the classic interference, a number of mid-frequency treatments are used to relieve pain and to exercise muscles. At frequency of 4000-Hz skin resistance decreases (not much redness), and therefore deeper tissues can be stimulated as well, with effect deep under. Primarily used for pain relief. Mid-frequency current has no positive and negative poles, so it cannot be used to administer medicine.Vacuum electrodes are frequently used, and this means that the effect of the electric current may be increased by the mechanical energy. Some forms are also used for exercising muscles, for intactly nerved but atrophied muscles, for example to stimulate thinned muscles after prolonged rest or under orthopedic cast."