TENS Therapy to Reduce Exercise-Induced Pain in Women With Fibromyalgia

The goal of this clinical trial is to evaluate the short-term (24-hour) effect of conventional transcutaneous electrical nerve stimulation (TENS) compared to Sham TENS on pain induced by resistance training in women with fibromyalgia. The main questions it aims to answer are: 1. Can conventional TENS effectively reduce pain intensity and unpleasantness during and after a resistance training session in women with fibromyalgia? 2. Is there a significant difference between the effects of conventional TENS and Sham TENS on exercise-induced pain in this population? Researchers will compare a conventional TENS group to a Sham TENS group to see if active TENS application during and after resistance training sessions leads to reduced pain levels and improved pain perception. Participants will: * Undergo a supervised resistance training session * Receive either conventional TENS or ShamTENS treatment during and after exercise * Complete pain assessments, measuring both intensity and unpleasantness, before, during, and up to 24 hours after exercise sessions

Study Design Randomization with minimization will be performed using MinimPy software to ensure group balance, considering the following factors: * Pain intensity, assessed using a pain scale (0-10) * Fibromyalgia severity, assessed using the Fibromyalgia Impact Questionnaire * Age Participants will be informed that different types of TENS stimulation may or may not produce a sensation, and this does not impact treatment effectiveness. Resistance Exercise Protocol The resistance training protocol involves a leg press exercise performed at a 90° starting angle. Participants will undergo a familiarization period, a warm-up, and a repetitions-to-failure (RTF) test to determine their 5-repetition maximum (RM). The Epley equation will be used to predict the 1RM. Participants will then perform two sets of 10 repetitions at 60% of their estimated 1RM, with a 1-minute rest between sets. A kinesiologist will supervise the training session. Data Collection Baseline Assessments: Demographic information (age, gender identity, height, weight, medication) Physical activity level (Physical Activity Questionnaire for Adults) Fibromyalgia severity (Fibromyalgia Impact Questionnaire) Kinesiophobia (Tampa Scale of Kinesiophobia) Treatment expectations (Numerical scale from -100 to 100) Blood pressure Repetitions to Failure Test (RTF) Participants will also complete a digital logbook via REDCap to record their pain levels at the end of the day and 24 hours post-exercise.