This study intends to evaluate dynamic respiratory motor performance as a valuable measure of pulmonary function in adults with late-onset Pompe disease. The investigators will adopt a strategy that includes comprehensive evaluations of respiratory volume, flow, and timing parameters during resting and loaded breathing. These evaluations will then be associated to the standard clinical measure of maximal inspiratory pressure, the static inspiratory muscle function, as well as magnetic resonance imaging of thoracic expansion and diaphragmatic descent at rest and with exertion. Outcomes in participants with late-onset Pompe disease will be contrasted to the function of age- and gender-matched control subjects. This approach will enable the investigators to evaluate the relationship between dynamic diaphragmatic function and respiratory motor function.