Frequency The number of cycles per second. 1 MHz or 3 MHz frequencies are commonly used in athletic training applications. Each frequency has its own characteristics and its selection depends on the depth of the targeted tissues.
1 MHz for deep tissue, 3 MHz for superficial tissue
1 MHz 3 MHz Beam profile Relatively divergent Relatively collimating Penetration Depth 5 or more cm 0.8 to 3 cm Maximum heating rate 0.2°C (.36°F) 0.6°C (1.1°F) per min per w/cm 2 per min per w/cm 2 “ Slow heater” “Fast heater” Heat latency Longer Shorter