Okay, but I have yet to see a MMA fighter utilize anything resembling "Tan-Sau" as demonstrated in that video during a fight. This includes Orr, who is clearly using standard MMA striking derived from kickboxing.
I was just using that as an example. However listen to what he is saying. He is basing everything in a simple fact. While I don't think he ever used the term "biomechanics" all humans, and thus all Martial Arts, can only move in so many ways. He shows a
tan in the video, though not as defense as one example. The arm position is consistent when he uses it, he just illustrates a non-typical WC way it can be used, and is used, by wrestling in an application other than a block. He trapped a hand with a
gum sau but it is something many other arts use as well, they may simply call it trapping and not have some flowery name. In the form both hands come down in
gum but in practice only one hand can be used. Yes the punches he did looked like kick boxing punches, but they also adhered to WC principles, the elbows were down, the fist with the palm facing in and coming from the centerline without rotation of the elbow or excessive use of the shoulder.
It's like what I did at work one night. A
fak sau is essentially a knife hand or "chop", in the form it is done parallel to the ground. Usually you see it as an attack to side of the head or neck while fighting an opponent. I did it after stepping behind a suspects leading leg in order to execute a take down. Now was that WC? Absolutely. Would someone look at it and immediately say "that was WC?" No they wouldn't, they would see what appeared to be a simple take down maybe, from watching Steven Segal movies, assuming it was Aikido.
Now if you look at the art standing alone and in its totality, yes WC is different than other MAs. However when you look at individual techniques, in practice, there are similarities with many other MAs, and tbh, there simply must be due to the very nature of biomechanics. The differences will be terminology and at times intent. He shows the example of the arm bar, in wrestling that would be to take the person down, in WC it would be to turn the opponent's blind side to the fighter so they can strike the vulnerable areas on the kidneys and maybe under the arm. The take down I did, by a wrestler would be to do what I did, follow them to the ground so you can restrain them. If I was doing it with WC intent it would be to ground and pound.
The problem is one of perspective I think. You see things from the lens of your experience. If that is kick boxing then you will see kick boxing, if it is WC you see WC. I learn two arts side by side, WC and Kali. There are times when I watch fights and say "yep that's something I don't do", then times I say "hey we do that in WC" or " we do that in Kali ". There are even times I say "he we do that in both WC and Kali." It is inevitable.