T.E.N.S stands for Transcutaneous Electrical Nerve Stimulation, meaning that the T.E.N.S pads send a micro-current through to the nerve supply in the skin that is over the affected area of your pain and or injury, By stimulating the skins nerves it will over ride the pain that is travelling from the deeper structures responsible for your pain, as a result it blocks your pain and providing an analgesic response.
T.E.N.S is a great tool to assist with chronic pain or very sensitive areas that are too painful for other treatment modalities.
T.E.N.S isn't suitable for all types of injuries so your therapist will suggest this as an ideal treatment option if applicable.