Nike air zoom structure 19 running shoes aw15 with its flymesh upper and triple density foam midsole the nike air zoom structure 19 running shoe gives the support and response needed for smooth and stable fast paced runs a triple density dynamic support system in the midsole helps slow the rate of pronation with firmer foam along the inside midfoot and wedged foam in the heel supporting your foot as it transitions through the footstrike the woven flymesh upper provides ventilation and support