Effects of an Acute Bout of Resistance Exercise on Fiber-type Specific to GLUT4 and IGF-1R Expression

The effects of resistance exercise on fiber-type-specific expression of insulin-like growth factor I receptor (IGF-1R) and glucose transporter 4 (GLUT4) was determined in 6 healthy males. The expression of both genes increased in Type I fibers (p < 0.05), but only GLUT4 increased (p < 0.05) in Type II fibers. These data demonstrates that an acute bout of resistance exercise can up-regulate mechanisms of glucose uptake in slow and fast-twitch fibers, but the IGF signaling axis may not be as effective in fast-twitch fibers.