That tells me you forgot the question.
So I'll rephrase it.
Well them
If it works in sparring, why doesn't it work in a fight? Why would the street guy get a broken arm, but the sparring guy wouldn't?
Second, I asked for a video of this technique working on someone that isn't playing along, to make sure we are actually talking about something here, and not one of the many existent 'untestable'(bullsh#t) techniques that exist all throughout tma. Like I said, I don't care about what ifs.
What specific technique I'm talking about is irrelevant, is part of why I didn't post a video. There are other reasons, but that's the biggest. We're talking about the concept of what speed things work at.
The reason I bring up the punch, is because a punch at half speed is significantly easier to avoid. The same is true of many grappling concepts. If I go for a double leg by crouching down and duck-walking towards you, it won't work. At half speed, it doesn't work against resistance.
The other reason I bring up the punch, is because most sparring is done with the effort to not injure your partner. Taking boxing for self defense would be pointless if you're getting concussions in class every other week. In light sparring, typically a tag to the head to say "gotcha!" is enough. Where in a match or a real fight, you throw as hard as you can to try and knock the other person out. Unfortunately, this can also lead to concussions, which is why I've heard some people quit MMA to focus specifically on grappling competitions.
But back to grappling. In light sparring or light rolling, if I can get into a position where the submission is available, my partner will usually tap. When I was a white belt, I went hard on every technique, and what ended up happening is I could barely use my hands the next day because my wrists were so sore from all the wristlock submissions we do. I learned when to go hard, and when to let my partner drill without sacrificing my body for it. If my partner does something that would result in my arm being broken had he continued, I will acknowledge his victory.
In a match, that's not the case. If my winning or losing a tournament is dependent on my tapping, I'm going to do everything in my power to not tap. If someone has me in a position where I am at the edge of my flexibility, but I have options to brace or roll out of the technique, I'm going to do that. I'm not going to just give you the submission (
and don't stop reading here), because I am going to try to roll or brace.
However, the only reason I
can roll or brace, is because you stopped to give me a chance to tap. If you wouldn't have given me a chance to figure it out, then my arm would be broken.
Let's go back to the punch. Because for some reason concussions are okay. If we're doing light sparring, I'm going to tap you on the head, because I don't want you to suffer permanent brain damage. If I were to punch that way in a boxing match or MMA fight, it wouldn't work. Because you would just ignore the tap on the head and keep going.
The same applies to grappling. In sparring, I can make it work, because people recognize what I could have done if I didn't hold back. In a match, it won't work, because people won't tap until absolutely necessary, and I'm not going to go full speed on the break because I'm not a sociopath. But in a real situation when I want to disable my attacker, I'm going to use it full force.