The Endorphin Pro 4 running shoe is a miraculous feat of engineering: snappy and responsive yet smooth and efficient. Something we achieved by fusing PWRRUN PB and PWRRUN HG together in the midsole – an industry first. A full carbon plate adds longitudinal stiffness and maximum metabolic efficiency. And the silky-smooth heel liner and integrated tongue system makes this marathon shoe feel like slipping on an old friend come race day.