An experimental verification of neurophysics treatment by executing a multifractal analysis of surface electromyography signals on trapezius, abdominals, and adductor muscles in athletes

Background: NeuroPhysics Treatment (NPT) is an exercise-based approach that was hypothesized to utilize the body's genius to trigger and organize self-healing. NPT involves mild resistance training exercises with extremely slow movements in an erect posture under therapeutic coaching. NPT was hypothetically based on system dynamics, chaos, and fractal theory. The aim of this study was to investigate this thesis by a cross-disciplinary approach. Methods: The differences between surface electromyography (sEMG) signals recorded on the trapezius, the abdominals, and the adductors of 10 healthy, male athletes at rest, during and following NPT were investigated by using the multifractal analysis based on Multifractal Detrended Analysis and with added Surrogate Data Analysis. Results: All the muscles represent complex systems, and their bio signal profiles constitute a multifractal. During the NPT treatment, these systems are subjected to continuous and differential transitions, enabling a continuous and differential rearrangement of the indices between different muscles and in the same muscles. Conclusions: This study is methodological and evidences the importance of always performing the multifractal analysis in sEMG studies and indicates the necessity for the same analysis of the EEG and of the R-R signals to obtain a whole picture of the involved dynamics, as a future prospect.