Electrotherapy modalities are used to assist pain reduction and the natural healing response via an increase in energy. Electrotherapy modalities include Transcutaneous Electrical Nerve Stimulation (TENS), Interferential Current (IFC) therapy, Ultrasound, and Laser. TENS and IFC therapy is the application of electrical stimulation transmitted through the body via electrodes for therapeutic purposes. Ultrasound is a method of using very high frequency sound waves to stimulate the tissue beneath the skin's surface. Laser therapy is a treatment that utilises specific wavelengths of light to interact with tissue and is thought to help accelerate the healing process. The benefits of these electrotherapy modalities vary from each modality but include pain reduction, increased localised circulation, preventing or retarding disuse muscle atrophy, and muscle re-education.