Analysis of motor units with high-density surface electromyography: methodological considerations and physiological significance.

This manuscript comprehensively examines current approaches for analyzing neural commands through high-density surface electromyography (HDsEMG) recordings and associated decomposition algorithms, discussing their applicability across multiple research settings. We present a detailed overview of EMG-derived analyses, including the extraction of motoneuron discharge properties, coherence analysis, estimation of persistent inward currents, and evaluation of motoneuron input-output gain. These approaches are discussed in the context of their physiological significance and are supported by robust statistical frameworks to ensure analytical rigour. Although some of these techniques are also applicable to intramuscular EMG, the present review focuses explicitly on advanced methodologies developed for high-spatial-resolution surface EMG. We summarize key analytical strategies for the interpretation of EMG data, integrating recent methodological advancements with established practices in HDsEMG decomposition and analysis. The aim of this review is to serve as a comprehensive and accessible resource for researchers in applied physiology investigating neuromuscular function. By highlighting both the physiological relevance and methodological precision of HDsEMG-derived techniques, we outline current best practices to support the accurate and meaningful interpretation of neural signals in human motor control research.