Third, exercise was unable to restore muscle and/or bone mass and strength in PPARβ−/− mice, contrasting with preclinical and clinical studies showing an improvement of muscle function by exercise through an increase in glycogen synthesis and a decrease in lipid accumulation in rodent models of type 2 diabetes (44, 45) and T2DM subjects (46, 47). Here, PPARD is linked to type 2 diabetes mellitus.