Contributors to increases in insulin sensitivity (M/I) in older men and women after 6 months of aerobic exercise training followed by 2 weeks of detraining. Sustained increases in capillarization accounted for approximately half of the exercise training-induced increase in insulin sensitivity after detraining when other intramyocellular mechanisms reverted to baseline levels. mo, month; wk, week; p-Akt, GLUT4, glucose transporter-4; AMPK, 5′ AMP-activated protein kinase; GS, glycogen synthase; phosphorylated AktSer473. (Reprinted from (14). Copyright © 2015 the American Diabetes Association®. Used with permission.)