Spectral Analysis of Bioelectrical Activity in Experimentally Provoked Referred Pain - Motor Alterations Related to the Network of Trigger Points.

Purpose: This study investigates bioelectrical changes in thigh muscles associated with referred pain following noxious stimulation of the gluteus minimus, focusing on understanding motor alterations related to the network of trigger points. While previous research suggested atypical autonomic activity, motor alterations in referred pain areas remain understudied. Thus, our aim was to investigate motor alternations using spectral analysis. Methods: Sixty-three participants were selected based on tests for atypical autonomic reactivity within the referred zone. The control group (CON) comprised 15 out of 48 healthy volunteers with negative test results, while the experimental group (EXP) included 13 out of 15 Polish national Short Track athletes with positive test results. They underwent a 10-minute surface electromyography session during gluteus minimus dry needling. Power spectral density analysis was then applied to assess the obtained signals. Results: Significant statistical differences in power spectral density were observed between the EXP and CON groups in thigh muscles, while no statistical differences were found in the pelvic girdle muscles. The most notable atypical bioelectrical activity was observed in the vastus lateralis, semitendinosus, and rectus femoris muscles. Results Importance: Visualization of motor alterations related to the trigger point network in the thigh due to noxious stimulation of the gluteus minimus trigger points. Conclusion: Noxiously provoked referred pain from the gluteus minimus muscle, confirmed by abnormal autonomic activity, is characterized by motor alternations of the thigh muscles, suggesting a network of latent trigger points. Further studies exploring this observed phenomenon for both active and latent trigger points can provide new insights into myofascial pain syndrome.