Shortwave diathermy (SWD) is a widely used clinical modality, which has been used in therapeutic treatments since 1928. The focused electromagnetic energy that is produced by shortwave diathermy machines works at the molecular level to move rapidly move ions in the treatment area. In areas of tissue containing blood vessels or muscle this produces heat.
The physiological response to tissue heating from shortwave diathermy is similar to other methods of heating, dilation of blood vessels and increased blood flow, which has been shown to alleviate pain symptoms, as well as muscle spasms. Shortwave diathermy has also been shown to decrease stiffness in joints, increase range of motion, and reduce swelling.
Referenced from Continuous short-wave (radio-frequency) diathermy by Geoffrey C. Goats. PhD, MCSP.