Ultrasound-guided Neuromodulation Percutaneous in Lower Back Pain

Participants received the percutaneous electrical stimulation intervention. Specifically, this consisted of the application of a square wave biphasic electrical current, with 3 Hz frequency and a 250µs pulse width, at the maximal tolerable intensity, to cause an tolerable muscle contraction. The application was 10 stimulations of 10 seconds, with 10 seconds at rest between stimulations. A trained physiotherapist performed the PNM intervention.