Facioscapulohumeral muscular dystrophy (FSHD) is one of the most frequent genetic muscular dystrophies. The disease is characterized by progressive muscle weakness and fatty infiltration. Janssen studied the muscle specific aspects of FSHD. Goal of the study was to uncover the pathophysiological aspects of FSHD using non-invasive MR imaging and spectroscopy. These studies showed (amongst other things) that, even though FSHD is described as a slow progressive disease, the muscle specific progression can be very fast. And edema usually preceeds the period of fast deterioration. Next to that it was shown that the rate of fatty infiltration can be decreased by adapting to an active lifestyle.