The article "Rate of temperature increase in human muscle during 1MHz and 3MHz continuous ultrasound" was based on a study where twenty-four college students were used to see the effectiveness of ultrasound for tissue temperature rise. The students had thermistors inserted into their left mediceps surae muscle belly, to measure the tissue temperature at different frequencies and intensities. Twelve students were used to measure tissue temperature at 1MHz and the other twelve were used for 3MHz. All were lying prone and participated in four applications of the ultrasounds at different intensities: .5,1.0,1.5. and 2.0 w/cm2 each for ten minutes.

The study proved that ultrasound is effective in heating tissues and that stronger intensities may have to be used to heat deeper tissues.