IFT which stands for Interferential Therapy is one of the types of electrotherapy used for the management of pain. The principle of interferential therapy is to cause two medium frequency currents of slightly different frequencies to interfere with one another. For example, if circuit A carries a current with a frequency of 4000Hz and Circuit B carries a current with a frequency of 3980 Hz, then the low frequency produced will be 20 Hz and this frequency is very useful in pain modulation. A new low-frequency current known as the beat frequency is equal to the difference in frequencies between the two medium frequency currents produced in the tissues at the point where the two currents cross.

It is basically used for the treatment of Chronic, Post Traumatic, and Post-surgical pains. The basic principle involves the utilization of effects of low frequencies (<250pps) without painful or unpleasant side effects. The major advantage of IFT is that it produces effects in the tissue, exactly where required without unnecessary and uncomfortable skin stimulation. This technique is widely used to elicit muscle contraction, promote healing and reduce edema.