INS and metabolic syndrome: Because we recognize metabolic profile, such as insulin sensitivity and resistance, as well as glucose and lipid metabolism, to be directly associated to muscle function as found in previous studies [37,38], a sub analysis of the obese group was performed, dividing groups according to an insulin resistance index using a 1.95 cutoff for Homeostasis Model Assessment (HOMA) [39] and NCEP ATP-III metabolic syndrome criteria [40].