I recall back in the day when there was nothing that was against the rules in UFC other than fish-hooking and eye gouging. Hell kicking someone in the nuts was allowed for a while. You would not be DQ'd even if your only strategy was going for the crotch of your opponent. Obviously things have changed a lot in MMA since then and almost all of it is for the better.
There is one rule that everyone kind of agrees is stupid, and that is the "12-6" elbows being banned. If you don't know what that is just imagine a clock and you thrusting your elbow like this on a person. There is speculation that this is banned simply because of how the move is hyped up in movies and how strip-mall karate classes break boards using this technique simply to ooh and aah the parents who are paying for their kids to put on pajamas and dance around for a few hours a week.
There are a couple of rules that don't get broken very often but they do get broken and there is a good reason why these are against the rules. You cannot "soccer kick" a downed opponent (kicking their head while they are down), you can't knee a downed opponent while standing, and you can't hit someone in the back of the head. These rules are all designed so that people don't die in the octagon or ring because if that starts happening, the sport will end up getting banned. Seeing as how it is a major money-maker, they don't want to see that happen and have to return to the days where you could only have these events in countries that truly don't give a damn about any laws.
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At the most recent Fight Night we saw the striking to the back of the head get pretty blatantly violated by Jacob Malkoun when he didn't just strike Cody Brundage in the back of the head but he did a full force full body elbow into the back of his head.
There are a lot of strikes that make accidental contact with the back of the head of an opponent who is scrambling to get away but this sort of thing is just a really dumb mistake on the part of Malkoun. When a standing opponent moves and your foot or fist inadvertently strikes them in the back of the head there is some room for stating that this was an accident and the fight can go on. There was no ability to make such a claim in this situation.
The really idiotic part of this on the part of Malkoun is that he was clearly the better fighter out of the two and had gained this top position in the first place because it was relatively evident that he was going to win this fight. I don't know if he just really wanted a first round TKO or what, but the fact that he would revert to a very well-known illegal move is just seriously stupid.
The other time that sticks out in my mind from recent history is when Petr Yan put a knee into the head of a clearly downed Aljamain Sterling. Both of these instances can only be blamed on the lack of discipline of the fighters because there aren't that many rules in MMA and seeing as how you are meant to be the best in the world, nobody can claim that they didn't know.
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For Yan, this resulted in his career going into free-fall although he might get another chance now that Sterling has lost the belt.
My apologies for this YT'ers self-promoting intro but it is the only footage of this I can find that isn't on Twitter. It also probably doesn't have the license to replay this footage so it will likely be taken down soon.
Brundage didn't allow the referee to raise his hand after the DQ victory and claims that he wanted to continue but the ring doctor wouldn't allow him to. I don't buy that for a second. Brundage was a massive underdog in this fight and a lot of people are talking about how this was the only way he could get a "W". I agree with this notion but it doesn't change the fact that Malkoun knows this is an illegal hit but did it anyway. You have to keep control of yourself in these situations and he didn't compose himself in what was an almost certain victory situation. I suspect that Malkoun wanted that fight of the night bonus and the to be part of a highlight reel with a huge KO victory. Well he is part of the highlight reel, that is for sure.
This doesn't bode well for either fighter though because this was an undercard middleweight fight in a Fight Night event that not many people watched anyway. It helps Brundage's record sure, but victories by DQ don't get you to the big time.
Nobody wins in this situation and I would imagine it will be a long time before we hear anything about these guys in the future.