To investigate TENS in low back pain patients, Melzack et al.7 carried out a randomized clinical trial comparing its effects with the effects from massage, in cases of chronic or acute low back pain. From the McGill Pain Questionnaire (MPQ), the TENS group was found to present a reduction in PRI of 69.5%, a reduction in PPI of 80.8%, a range of movement improvement and a reduction in pain intensity (VAS) of 84%. The effectiveness of the interventions, as determined by the patients’ percentage improvement, was 38% in the massage group and 85% in the TENS group. There was no statistically significant difference between the groups.