Effectiveness of exercise training in increasing ultrasound-mediated improvements in body composition – preliminary results

Ultrasound treatment is commonly used in aesthetic medicine as a non-surgical method to reduce localized fat deposits. Transdermal focused ultrasound waves cause adipocytes cell membrane destruction: this lead to the liberation of the cell content in the interstitial space which, in turn, may increase high-energy substrate availability in the bloodstream. High-energy substrate utilization is augmented by both aerobic and resistance exercise: fat is the major fuel during low-intensity aerobic exercise whereas resistance training increases post-exercise high-energy substrate utilization. Although ultrasound treatment has been proved to be a safe and effective method in reducing localized fat deposits, the possible adjunctive effects of aerobic and resistance exercises has never been studied. The aim of this study is to compare the effectiveness of combining exercise training and multiple ultrasound treatments (EU group) versus either exercise (E group) or ultrasound (U group) interventions alone. Sixteen young female subjects were randomly assigned to the EU (n=9; 29.3±3.8yr) and the U (n=7; 32±4.9yr) groups, while the recruitment of the E group is still in progress. Intervention of the EU group consisted in 10 ultrasound treatments (1/wk) plus combined walking and resistance training (2/wk x 10 wks). U group intervention was identical but restricted to the ultrasound treatments. Before (t0) and after (t1) the intervention, subjects underwent the following measurements: height (m), weight (kg), body circumferences (cm), skinfold thickness (mm), 6-minute walk distance (6MWD) covered (m) and the number of steps taken (a step counter was used) during a 6-minute walk test. Measurements were used to estimate body mass index (BMI) and fat mass (FM), while the 6MWD and the step count were used to prescribe the walking speed (step•min-1) of aerobic training in the EU group. Once-a-week, subjects exercised no later than 24 hrs after the ultrasound treatment. E group has not been recruited yet, thus preliminary results focus on single-group (t0 vs. t1 in either EU or E group) and between-group (EU vs. U of t1-t0 differences) comparisons (Wilcoxon matched-pair test or Mann-Whitney U-test for single-group or between-group comparisons, respectively). Single group results evidenced, at t1, significant reductions (values in %) of BMI (EU -3.4; U -3.1), weight (EU -3.3; U -3), FM (EU -5.5; U -4.9), and hip (EU -3.6%; U -2.1), umbilicus (EU -2.6; U -1.7), right thigh (EU -4.4; U -3.9), and left thigh (EU -3.8; U -3.3) circumferences, whereas 6MWD improvement was non-significant (EU +5.6; U 0.8) in both groups. Although between group comparisons revealed no statistical differences among body shape and composition, single group results clearly showed superior effects of the combined intervention. Furthermore, 6MWD - which represents a reliable cardiorespiratory health index - as expected showed a significantly higher improvement in the EU group compared to the U group.