Cycle Training Increased GLUT4 and Activation of Mammalian Target of Rapamycin in Fast Twitch Muscle Fibers

Abstract

Progressive intensity stationary cycle training of previously sedentary subjects increased muscle insulin-responsive glucose transporters (GLUT4 and GLUT12) and decreased the fructose transporter (GLUT5). The increase in GLUT4 occurred primarily in Type II muscle fibers, and this coincided with activation of the mTOR muscle hypertrophy pathway. There was little impact on Type I fiber GLUT4 expression and no evidence of change in mitochondrial biogenesis.