on a related note though, how do people "practice" with steel toed boots? they're freaking heavy!! when i train, it's always either barefoot or on MA shoes, but when i'm at work i usually wear steel tipped boots due to the nature of my job. i tried kicking with it but felt so damn awkward doing it. usually even losing my balance if i go full power. (my shoes have steel insoles tips- reaaaaly heavy) i used to run/jog with ankle weights, so the weight isn't really a very big issue- maybe it's where the "weight" is located. (the soles and toes- instead of the ankles)
Surely it depends which kick is used as to which part of the foot/leg yto kick with. Personally, if i was tryin to disable i'd go for a thrust kick (possibly wrong name i'm bad with them) to the kneecap using the heel of my foot. Should break the knee, giving plenty of time to walk away. Also, if you've got shoes on it houldn't hurt a bit.
Like anything else, you use the tool most applicable for the job. I find it odd that people are still talking about "best" techniques. I say that if it lands you have used the correct kick.
Shin is great for delivering damage but there are some targets that require a more precise tool. The heel, if properly inserted into your opponents eye is very damagind. A turning kick using the ball of the foot instead of the instep can target an opponents nose, temple or ear fairly well. The floating rib is usually targted by the instep easier than by the shin, and causes the opponent to skip a breath.
Shin, no question. For ages, I was taught to kick with the instep. Now I'm kicking with the shin, it's a much more powerful and useful kick. More important than the point you choose to make contact with is the method of chambering/not chambering. For round kicks, the non-chambering method I'm currently learning in MMA seems a lot better, and for straight kicks I find chambering adds a great deal of power to the kick.
I would say that if you're going for a quicker, more jab-like kick, go with the in-step. But if you want power, definitely use your shins. Also, as Ikken said, if they move back from your shin kick, you could easily hit them with your in-step and if they move forward, there's always the chance they get the knee.
