Interferential current: Uses two biphasic sinusoidal AC currents that are designed to intersect or “interfere” with each other.  Electrodes may be placed so they surround a painful area. Interferential current is effective in relieving pain and reducing swelling. According to the theory behind IFC, pain needs to be relieved because it produces spasms and unnatural movement within the body. These restrictions can lead to even more injuries. The IFC current has an analgesic effect - it deadens the pain - and a vasodilatory effect on the tissues, which means it causes the blood vessels to dilate or expand. Swelling is reduced because the permeability of the cells increases and venous and lymphatic flow are also improved.