side kicks and spin kicks that i know i use my heel, front kick is the ball of the bottom of ur foot, round house kicks and others are usually at the top of my foot. i figured it takes time to get the pain away, because my blackbelt friends foot is very flat compared to mines, and he can kick practically anything and not experience that much pain. u ever heard of those guys that roll down their shins very hard with base ball bats, then kick trees? thats crazy.