Therapeutic ultrasound delivers alternating compression and rarefaction of sound waves at 0.7–3.3 MHz. Maximum energy absorption in soft tissue occurs from 2–5 cm depth, primarily targeting connective tissue — ligaments, tendons, fascia, and scar tissue.
Applied via a transducer in direct contact with the skin, with coupling gel to reduce friction and assist transmission.
Ultrasound is delivered continually at a set intensity. Generates thermal effects by stimulating tissue regeneration, changing cell membrane permeability, and increasing intracellular calcium.
Delivered in short bursts over a period. Produces non-thermal effects to increase tissue metabolism, enhance fibrous tissue extensibility, and elevate pain relief.
Ultrasound is delivered continuously but intensity oscillates between the selected level and a minimum of 0.5 W/cm². Requires minimum set intensity of 0.6 W/cm². For example, at 1.5 W/cm² the output cycles down to 0.5 and back up over the set duration.