The MR protocol includes the special T1 weighted sequence DIXON (1x1x3mm3; TR: 5.31ms TE: 2.46ms) enabling acquisition of muscle and fat images at 3 Tesla (Magnetom-Skyra, Siemens AG, Erlangen, Germany). The MR scans will consist of 400 axial slices covering from L1 to the ankle resulting in a total scan time of 22½ minutes.