Effects of Interferential Therapy Parameter Combinations Upon Experimentally Induced Pain in Pain-Free Participants: A Randomized

Background. Little evidence exists regarding parameter selection for hypoalgesia using interferential therapy (IFT). Objective. This study investigated segmental and extrasegmental hypoalgesic effects of different IFT parameter combinations upon experimentally induced pres-sure pain threshold (PPT) in pain-free volunteers. Design. The participants were randomly assigned to 6 groups: control, placebo, bipolar constant amplitude modulation frequency (AMF), bipolar sweep AMF, quad-ripolar constant AMF, and quadripolar sweep AMF. Setting. The study was conducted in a university laboratory. Participants. One hundred eighty adults who were healthy and pain-free partic-ipated in the study. Intervention. Interferential therapy was delivered to all groups at high, to-tolerance intensity and at high AMF. Stimulation to the dominant forearm was delivered for 30 minutes, with monitoring for a further 30 minutes. Measurements. Pain pressure threshold was measured at the area of first dorsa