The writer, Gary Dix, is a teacher of computing. He also has a degree in psychology.
There are three zones around you: an outer zone—the fence—a middle zone, and finally at close quarter, the inner zone.

In self defence each zone has its own moves, which serve different purposes. The outer zone is to keep people out; it's where you keep the scary people.
The closer you get the more moves you have available to use but the more vulnerable you become. The mid range, the sparring range, is where you measure yourself off against your opponent, trying to judge his abilities. In the closest zone your weaknesses become evident and your vulnerabilities obvious. It’s a place where the other persons is ‘in your face’, it's sweaty, can be smelly and physically dangerous.
This concept of zones can also be seen in our relationships with each other. We have an outer zone of contact with others, with few moves, that are often used just to maintain distance, in this case social distance. We keep in the outer range those that scare us, the big guys, the bad guys, people we can’t handle, people we don’t want to get close to. What passes for a ranging kick, may be a morning ‘hello’.
We also have a mid range of relationships, with whom we have more techniques. We let into the mid range those we are equals of, those we know we can handle, and those we are familiar with. We have social niceties and verbal parries. "How was your weekend? How’s your day going?"
Finally the close inner zone. We have many different techniques; in this zone it gets personal; you get up close with your partner, it's sweaty, can be smelly and sure is painful. But you come away really knowing something about the person, knowing where their limits are, and knowing what their weakness is. Knowing too how vulnerable you are, and being known, being revealed, to others.
Just where are we with each other as colleagues and workmates--are we parrying each other off at a distance, dismissing with a few moves, or closer in, engaging each other? Is there someone who reaches the inner zone, someone you relate to who knows your strengths and weaknesses?
Finally, and most important, there is a third area which operates with zones as well. That is the area of your relationship with God. In the outer zone, are you keeping distance from the things that God wants, but you find threatening or different?
Maybe God is in your middle zone, a place where he visits on Sundays, funerals and Easter. A socially and culturally structured relationship. Or maybe you have let God into your inner zone, where he works to expose your strengths and weaknesses, and where by his grace you are made strong.

Is he there, close-quarter grappling for your thoughts, for your motivations, for your love? Do you let him in that close, where he knows your weaknesses, where he anticipates your thoughts, your moves, or do you hold him off, afraid who would win, comfortable in a place where you can keep him at arms distance?
Jacob wrestled with God when he was in fear of his life after cheating his brother out of his birthright God revealed to Jacob his weaknesses and Jacob, afraid he was going to die, wrestled in his innermost being. The result transformed him into the nation of Israel.