I HAVE PURCHASED OTHER PROPET SHOES, AND THEY ARE COMFORTABLE FOR TREADMILL USE.  THIS SHOE, HOWEVER, IS PRESENTLY UNCOMFORTABLE AS THE HEIGHT OF THE BACK OF THE SHOE IS TOO HIGH AND RUBS WRONG.  HOPEFULLY, THIS FEELING WILL GO AWAY IF I PURSUE IN WEARING.  THE COST WAS BETTER THAN AT OTHER SITES SO I REMAIN HOPEFUL.