Lung volume variations during quiet breathing (grey lines) and vital capacity (blue lines) in an healthy subject (left) and a muscular dystrophy patient (right). Lung volume variations during quiet breathing (grey lines) and vital capacity (blue lines) in an healthy subject (left) and a muscular dystrophy patient (right). Muscular dystrophy patients are characterised by reduced vital capacity, and rapid and shallow breathing at rest, i.e. reduced tidal volume and increased respiratory rate. RV: residual volume; FRC: functional residual capacity. Antonella Lo Mauro, and Andrea Aliverti Breathe 2016;12:318-327 ©2016 by European Respiratory Society