When analyzing my own Krav Maga training, I often think of the mantra “hands, body, feet.” That is the order of movement for many techniques in the system (except, of course, kicks), and for practically ALL the weapons defenses.
The hands move first; then the body defense is made, then the feet move. These movements can and should overlap, but there is an order of events, because the hands can move faster than the body, and you usually begin a body defense much earlier than your feet are ready to move (especially when surprised). This order of events, hands-body-feet, is fairly obvious in something like Gun from the Front, but it applies equally to a knife defense against a downward stab. Of course you should burst forward, but even before that, your hands must be rising to make the defense, and your body should lean forward slightly to add strength and stability, and to defend earlier. If you think of moving the feet before the hands, you will often be late, but think of the hands leading the body and the body leading the feet, you will usually make strong, aggressive defense, and you will usually be earlier than if you try to move your feet first.
This way of thinking doesn’t always jibe with other schools of thought and, frankly, I respect some of the teachers in those schools very much. I know good fight coaches that will teach a hook punch with the body and shoulder turn first and the hand following slightly behind. I get why they do it – it lends a whip-like feeling to the hook punch. But, truth be told, I’ve watched their hook punch compared to mine, and I think the final result is about the same. Their hands don’t really trail much behind the shoulder movement; my hands don’t lead too far in front. It’s more a philosophical difference and a difference in overall systemic emphasis.
As an overall approach to self defense, though, I believe this “hands-body-feet” philosophy is an important one. Like all rules, it has exceptions, but if you look at many techniques from this point of view, you’ll be able to executive more effectively from a wider variety of attacks. Try it, and let me know what you think!