Electrotherapy refers to the transcutaneous (i.e., through the skin) delivery of electrical currents to the nerves and muscles. Often used as an accessory treatment for a variety of injuries and conditions, electrotherapy can help reduce pain and swelling as well as improve range of motion and mobility. It often is considered an effective treatment because the waveform of the electrical current allows for very deep muscle penetration, thus eliminating the need use needles. This type of treatment is commonly used to relieve pain associated with strain or sprain injuries or to relax back and neck spasms. It increases blood circulation in the treatment area and can help strengthen muscles, tendons, and ligaments, thus accelerating the healing process. It also is effective in lessening the severity of the symptoms associated with tennis elbow, carpal tunnel syndrome, shoulder injuries, knee injuries, chronic muscle conditions, and post-surgical pain. Furthermore, it can help slow or prevent muscle atrophy due to inactivity as well as speed muscle recovery following intense training or overexertion. Electrotherapy is considered a safe and comfortable procedure. While most patients report little to no pain from electrotherapy, some people experience a mild tingling sensation and gentle pressure while receiving this treatment.