Generally speaking, BJJ players are terrible athletes. Weirdly it's one of the few sports where strength training is actually discouraged. Freakin' bobsledders take strength training way more seriously than a lot of BJJ guys. Don't get me wrong, there are plenty of BJJ competitors who are tremendous athletes. However, the mainstream jiu-jitsu community has been inundated with the idea that it's a cardinal sin to have muscles and use them.
Historically, martial arts culture has largely been made up of skinny little wimps who got bullied and tried to remedy the problem by learning how to fight back. The good schools of martial arts in my opinion are the ones that help the students develop strength (physical and mental) and teach them how to use that strength efficiently. The bad schools are the ones that don't help the students get stronger (neither physically nor mentally), and tell them a beautiful lie that if they just put move around the right way, they'll easily be able to beat larger, stronger, more athletic opponents, in spite of having the constitution of a wet noodle.
So when BJJ guys who can't tell the difference between a squat and a deadlift see actual athletes competing in jiu-jitsu, they lose their minds and attribute all athleticism to performance enhancing drugs. Weirdly, it the same people preaching that size and strength don't matter that also get most bent out of shape about the possibility of BJJ competitors on steroids.
I once had an immensely powerful strength athlete come to my gym to learn some jiu-jitsu. He was a very humble, teachable guy, and strong as a gorilla. Over twice my size and objectively 8 times stronger. I soon realized that I couldn't effectively teach him because I was simply too weak and too small to use my technique when rolling with him. I had frequently rolled and competed against larger stronger opponents before, and even competed with some big dudes and won shiny gold medals in openweight grappling tournaments, but nothing like this. The difference between fighting someone 30% bigger and stronger vs a freakin' strong-man about to crush a human skull in one hand is night and day. It was like a grown man fighting a toddler, and I was the toddler.
(It should always be remembered that good "technique" is nothing more than an efficient use of strength and power, while bad "technique" is an inefficient use of strength and power. All human movement is a use of strength and power.)
But instead of chalking my failure up to someone else's alleged steroid abuse (he was 100% natural, by the way) I dedicated the next year of my life to strength training and dietary changes that resulted in adding 30 kg to my frame (a very skinny 64kg to a lean 94kg, starting at 6% going up to 9.3% body fat, at 185cm height). And yes, I have body composition tests from my annual physicals to prove it. I don't care how unusual or impossible that sounds to you based on what you've read on wikipedia, that was actually my experience. (Apparently a lot of people think it's impossible for a skinny dude to gain that much weight in a year without getting fat without the use of drugs.)
After which I was frequently asked what I was "taking" to bulk up. And everyone stared in disbelief when the answer was "food, sleep, and consistently lifting heavy things." (specifically going from 1800 calories a day to an average of 5500 calories per day, and a major focus on deadlifts and squats)
Ultimately, I was still much smaller and weaker than my strong-man student, but I had become just about strong enough to teach technique by example rather than apologizing for jiu-jitsu by effectively saying "Well, against normal sized humans, this usually works."
After relating this story to a certain BJJ black belt, he suggested that if my technique was better, I would have been able to easily control and submit a huge strongman without having to become stronger and more athletic myself. I suggested to him that "technique" can never nullify the laws of physics. There's this beautiful lie that's been propagated throughout the martial arts community for decades (and the BJJ community is not exempt from this kind of thinking) that a cerebral understanding of "technique" will allow the martial artists to easily defeat anyone regardless of stature, strength, or athleticism. And I believe that kind of magical thinking is responsible for holding potential athletes back.
Naturally, this black belt (who himself is a pretty big guy) shrugged this idea off as a silly notion from someone inexperienced who doesn't understand the true spirit of jiu-jitsu, or whatever. So I proposed this hypothetical scenario:
A fight between the world's best,most technical BJJ guy and a silverback gorilla. How does that fight play out? Bear in mind, even the worst BJJ black belt on Earth is still a pretty dang good grappler (that could change in 20 years or so, if BJJ continues to sell itself out and water itself down to the lowest common denominator like so many other martial arts have over the years)
The gorilla doesn't even know jiu-jitsu. Easy right? Probably not, since that gorilla was also 6 times stronger than the world's strongest man when it hit puberty. It's also much bigger and faster than the blackbelt by a huge margin. It's so big and so wide, that even if the blackbelt were to get behind it, he couldn't even get his hooks in. The muscles connecting the gorillas' head to it's shoulders are so thick and so broad that the black belt couldn't even fit his arms around the apes' neck to attempt a rear naked choke, let alone finish one. But let's pretend that somehow the blackbelt managed to catch that over-sized simian in a perfect armbar- everything is technically right. All the pieces are in place. Here's what happens next: anything the gorilla wants.
You can't hyper-extend his arm if he doesn't want you to. The gorilla can do curls against your leverage. That's not a technical failing on the part of the blackbelt. Not at all. It's because it's a gorilla! That animal has a capacity to inflict and withstand violence far beyond what any unarmed human can endure or inflict.
Take the best strongest, biggest, most athletic fighter in the world, heck, take five or six of them at the same time, and I'd still put my money on the gorilla to win that fight. And that has nothing to do with how good their technique is- it's a matter of physiology, resulting in unconquerable strength, power, and resilience.
Now, let's go to the opposite end of the spectrum: a new student walks into your gym and wants to learn jiu-itsu. She's the most tiny, unathletic weakling you've ever seen. Even the most basic movements are a serious challenge for her against any level of resistance, even after diligently working on them for months. But she wants to learn how to grapple because she believes it will allow her to fight off bigger guys- and in her case, those guys are 3-5 times bigger and 20+ times stronger than her.
This new students saw UFC 1 and got really excited about the underdog aspect of "little" Royce Gracie choking out big dudes in the octagon. But day after day, month after month, in the gym she's stuck on the bottom getting squashed by even the smallest, weakest, least experienced training partners. Day after day, month after month she sees her peers surpass her. She struggles and sweats and does the work and then some, but doesn't seem to get the result because she's just too small, and too weak to compete with "normal" sized people.
What do you tell Gracie when she comes crying to you that the "technique" isn't enough. Do you tell her that once she acquires enough knowledge that gravity will no longer apply? What do you tell her when she says "you don't know what it's like to be in this situation!" after you give her the whole "just stick with it, it doesn't happen all at once" speech?
You know what I told that Gracie? Start lifting. Because you're fighting gorillas, and you need a better a weapon.
She lifted for a while and saw some marginal improvements, but it wasn't happening fast enough for her. It was still like watching a small person trying to fight a giant bodybuilder every time she got on the mat. One day she said "This makes me want to take steroids just so I can have a chance!" And eventually she stopped coming back. And I took that pretty personally as a failure on my part. I kept telling myself there was more I could have done as a coach, or some obvious technical aspect I was overlooking. But no, it turns out that it really is super hard to win when you're at an extreme physical disadvantage, and not everyone can handle that kind of pressure day after day, month after month without ever seeing any tangible evidence of progress. Can you blame them?
Back on topic:
Yes, some people take steroids. Some people cheat at sports. Some people break the rules. I'm not talking about them. I'm talking about the droves of internet warriors who have never spent any significant time under a barbell that can't wrap their minds around the idea that a human being can have visible muscle striations without pharmaceutical help.
And yet time and time again, we're still hearing the dogma that muscles don't matter. It's an absurd pseudo-egalitarianism when we equate all martial artists of the same belt level as having the same capacity to fight. Nope. You can't tell me that skinny dude from BJJ After 40 (bless his heart) is the same level of jiu-jitsu as Andre Galvao just because they both wear a black strap around their pajamas. Bigger isn't always better, but is sure does make a difference.
Too many weak martial artists want to believe that the strong ones are using an unethical advantage. Everyone wants to believe in a magic pill that turns you into an athlete, a bodybuilder, or a fitness model. The martial arts community is no exception- except instead of wanting to buy the pill, they want to believe everyone else is.