Immediate analgesic effect of transcutaneous electrical nerve stimulation (TENS) and interferential current (IFC) on chronic low back pain: Randomised placebo-controlled trial

To compare the immediate analgesic effect of transcutaneous nerve stimulation (TENS) and interferential current (IFC), with different combinations of parameters, in individuals with chronic low back pain (CLBP). 280 individuals with CLBP were included in the study, both genders, randomized in 8 groups: GI2KHz/100Hz, GI2KHz/2Hz, GI4KHz/100Hz, GI4KHz/2Hz, placebo interferential group (GIP), GT100Hz, GT2Hz, and placebo TENS group (GTP). All individuals underwent a single application of TENS or IFC for 30min. The assessments were carried out prior to the intervention, as well as immediately after, with the following outcomes: pain intensity (Numeric Pain Rating Scale-NPRS), qualitative pain characteristics (McGill Pain Questionnaire-MPQ), and pressure pain threshold (PPT) by pressure algometry (PA) in 4 points of the low back region. In the intergroup comparison of NPRS, all intervention groups showed greater pain reduction compared to GTP (p