I also studied Judo and was a state champ wrestler. He was running. Thus you use his momentum against him. But yeah if he's going low right into you I'm probably going on top with an arm under the chin in a choke hold and pushing his face into the concrete under my weight. But I'm not "Smarterthantheaveragebear." If he says he's gonna take the guys knee out.. it's probably because ... he's gonna take the guy's knees out.
Uh huh....well believe what and who you please....this "bear" character is a fraud....Further, there's no way in the world you want to close quarters with a guy of that size and strength and you're not going to side-step him because he's too wide....one of his arms with gather you in and you're fucked. Any streetfighter knows that....any martial arts instructor will just laugh at the idea...like I have been.
The way you side step a big guy is to feign one direction then as he shifts his weight to the direction you feigned you go the other direction. Anyone that's played football knows that.
A guy that big, I'm faster than him, sidestepping him and getting enough distance for a snap kick as he's charging me isn't that difficult.
In fact, probably no less difficult at all then getting behind him and getting him into a choke hold.
BUT, my point is, most LEOs are not trained enough to do EITHER thing, so the gun is the only option.