Interferential electrotherapy is the use of small electrical impulses to repair muscle tissue, stimulate and control the healing and repair processes. Interferential uses the physiological effects of low-frequency electrical stimulation. The core benefits of this treatment are to promote healing, pain relief, muscle stimulation, increased blood flow and reduced swelling in the area. Ultrasound therapy uses high-energy sound waves (those above the range we hear) to help ease painful joints and muscles. The therapist guides the painless waves into the body from the head of an ultrasound machine.