Martial D
Senior Master
Yes. The distance doesn't change. At least, you aren't changing the distance. But YOU are only 50% of the equation.The moment that you move your leading leg, the moment that the distance between you and your opponent has changed.
When you move your back leg first, you don't have to take any risk. If your opponent's leg can't reach to your leading leg (and your body), when you move your back leg, his leg still can't reach to your leading leg (and your body). So when you advance your back leg, the distance between you and your opponent hasn't changed yet. You are still safe.
Before your back foot landing, if you also move your leading leg, you can combine 2 moves into 1 move. This footwork is just like the jumping kick. You can cover more distance, you can also reduce your risk.
View attachment 26735
Here is another example that you combine back leg move and leading leg move into one move - a hop.
The other guy also moves. And once your feet are together you can be easily double legged, single legged, or hip tossed. In that moment you have no base.
Where as if you move first with your lead leg, and take your hips with you, you are in no danger of being swept.