Both human activity profile scores, the maximal activity score and adjusted activity score, were reduced (Table 2). The 6-MWT, sit-to-stand, and stair-climbing measurements in MHD patients were 71.5, 60.7, and 161.2 %, respectively, of the values obtained from normal controls (p < 0.001 for each comparison, Table 2). The reduced distance walked during the 6-MWT occurred even though no patient stopped walking.