Shaping exercise performance and neuromuscular fatigue through neuromodulation: unleashing the power of brain-muscle connections

Neuromuscular fatigue represents a reduced ability of the muscle to express force during a motor task. The literature proposes protocols to limit the development of this physiological event by modulating the peripheral components (e.g., muscle). On the other hand, repetitive transcranial magnetic stimulation is a widespread tool for regulating neuronal networks and brain functions in clinical and research settings. However, theta burst stimulation (TBS) protocols, which are faster and equally effective, remain confined to the clinical sphere for treating neuropsychological disorders. To date, the still unclear physiological mechanisms, and the high variability of response to TBS limit its wide-ranging use and application. Instead, thanks to the induction of long-term excitatory (intermittent TBS) and inhibitory (continuous TBS) effects, TBS may be a valid approach for the modulation of the central components also in the field of neuromuscular fatigue. Therefore, this thesis aims to verify the effectiveness of excitatory and inhibitory TBS on the components of neuromuscular fatigue, and its adjustments during physical exercise in young and healthy subjects. Chapter 1 provides a brief introduction and a review of the literature with the necessary information to understand the phenomenon of neuromuscular fatigue, the tools for its verification, and the related physiological mechanisms. Subsequently, in Chapter 2 the objectives and hypotheses pursued in this thesis are presented. In Chapters 3, 4, and 5, you can find the results of original studies on the topic in question. Finally, Chapter 6 provides a summary and overview of the results, highlighting the strengths and limitations of the work, and providing ideas for future investigations.