ABSTRACT
Therapeutic modalities that alter hemodynamic parameters may have a dramatic impact on the viability of living tissues. The purpose of the current study was to investigate the response of blood flow velocity to various treatment parameters of therapeutic ultrasound. Twenty healthy volunteers attended six randomly selected, 15-minute treatment sessions of the following parameters: Tx-1 = 1.0 MHz at 1.5 W/cm2, Tx-2 = 1.0 MHz at 1.0 W/cm2; Tx-3 = 3.0 MHz at 1.2 W/cm2; Tx-4 = 3.0 MHz at 1.0 W/cm2, Tx-5 = sham; and Tx-6 = control. Ultrasound was applied to a circular area over the triceps surae muscle mass. Blood flow velocity in the popliteal artery was assessed after 5, 10, and 15 minutes of ultrasound and at two posttreatment intervals via a dual frequency, bidirectional ultrasound Doppler. A two-factor analysis of variance (p < or = 0.05) with repeated measures for treatment and time was performed on the data. Groups Tx-1 and Tx-2 showed significant increases in blood flow velocity when compared with the control and all other groups. The sham group showed significant increases in blood flow velocity when compared with the control group. Group Tx-3 and Tx-4 showed no significant change when compared with the sham condition. The results of the current study indicate that 1.0 MHz ultrasound delivered at 1.0 and 1.5 W/cm2 to the triceps surae musculature as described in the present study can increase the blood flow velocity in the popliteal artery.