Four men and 8 women who were healthy, college-aged volunteers (age=22.2±2.25 years, calf subcutaneous fat=7.2±1.9 mm) participated in our study. Each participant was screened for disqualifying conditions that included pregnancy, fever, peripheral vascular disease, infection, injury to the triceps surae muscle in the 2 months before the study, compromised circulation, compromised sensation to the area being treated, and subcutaneous fat thickness of the calf greater than 15 mm.