Perhaps you have heard of the metaphor ‘to draw a line in the sand.’ This is famous phrase which can trace its origins to a very long time ago. Basically, the meaning is that you are emphasizing a point at which, when crossed, you will act. This can be for any reason, and but it usually has the connection with an ultimatum, meaning you are telling someone (maybe yourself) that if you go ‘this’ far (meaning to the line), I will respond in some manner.
I like to use this phrase when coaching students in sparring. Many lower ranked students have trouble with distance to their opponent, and often times don’t react when the attacker gets in their zone. Getting familiar with your distance to your opponent is an important part of learning to spar and becoming effective. I will tell a student that they must have in their minds a point (distance) at which if their opponent breaches, they will do something. This is their line in the sand. Suppose, for example, that 2 students are about to point spar and the referee makes sure they are apart and then says begin. If you are not going to attack but instead wait to see what your opponent does, when do you react? You must have a line in the sand. If your line is drawn too close to you, then your opponent might be able to score against you before you can do anything. If your line is too far away, you will react without the need to, likely wasting energy and telegraphing your intentions to your opponent. But, imagine if your line was just at the edge of your kicking distance. If your opponent gets to that line, you can react and successfully kick them. If they are outside of that line, you are for the most part out of danger for the moment and can conserve energy. If they are within that line, they are definitely in your space and you should react with kicks or hand strikes.
The point is that you must learn where your line in the sand is. You must understand your body and the space around it, and be able to discern when you need to react and when you don’t. Of course, there are critical distance movements to close distance and there are foot maneuvers to create space, but you must have a base level of understanding about where your range extends to and where it does not.
One way to develop this skill is to use a heavy bag or a ‘Bob’ dummy to practice kicking to the edge of your range. Work on moving around but yet keeping the distance to the object the same, which is just at the edge or your kicking distance. With time, your body will develop an understanding of that space and you will be more effective in determining where your line in the sand is. You want to get to the point where the only time someone gets within your line (without a greeting) is when you want them to because you have a nice technique waiting for them.