ActuAlly about most of the world comment, i do belive most Chinese Martial arts belive in kicking with the foot and I'd also wadger that most japanese do aswell, so thats like over a billion there dude, plus MA's like TKD, Karate, Gung Foo,Capoiera(sp?) and JKD(not positive on this one tho) all use the foot mostly and are pretty popular in the western world, so I'd say the majority of people belive the foot is the way to go, as for kicking with the instep, i've gone throught about, 3 boards that are about an inch thick placed back to back. I'm sure I'm not making an record but just saying insteps aren't gonna break as easily as people belive. O, and I would never suggest any one begin on an 800lb bag, because if it's bottom heavy, which most bags usually become, ur gonna hurt no matter if u use shin or foot.