We call both versions a roundhouse, because your support leg, hip and striking leg use the same motion throughout. the only difference being the striking surface. We did learn a third, using the toes, but we don't practice it as we have no realistic application nor are we conditioned for it. We use primarily the top of the foot and occasionally the ball of the foot, depending on what you're trying to kick. A harder surface may injure the top of your foot, unless you have shoes on in which case this is much more forgiving. The ball is great for barefeet against a hard object, but as I believe Nick mentioned, with shoes on, getting the proper angle may be difficult. I wear softer sole shoes for that reason. (even dress shoes). I've only thrown a roundhouse for effect on one occasion and it was with the ball of my foot.