Myths and methodologies: Invasive and non-invasive assessment of respiratory muscle activity in humans

Survival relies on neural respiratory drive from the medullary respiratory centres to activate the respiratory muscles for breathing. Accurate assessment of respiratory muscle activity, as an estimate of neural respiratory drive in humans, will facilitate a greater understanding of respiratory physiology, the pathophysiology of diseases and injuries, clinical investigations and the neurophysiology of breathlessness perception. Here, we highlight the methodologies to measure respiratory muscle activity, their appropriate application, the potential limitations of the data and their safety and feasibility considerations. These recommendations can be applied to all skeletal muscles.