Daniel Bryan walks backstage after finishing a match, something he's done thousands of times over the course of his 19-year career. Instead of heading right to the locker room to shower and change before driving on to the next town, Bryan has to first take the number eight and multiply it by three, multiple that number by three and divide it all by four. If he can't come up with the correct answer, he's not wrestling.

This is the cost that Bryan has to pay if he wants to wrestle for the WWE.

It's just one of the tests a WWE doctor performs on Bryan after he's endured any physical activity in the ring. First, he gets his eyes checked. Next, he goes through a series of balance tests. And in the final step, as we've covered, the doctor asks Bryan to solve a math equation -- nothing too complicated, but something challenging enough to determine if his brain is functioning properly. The series of tests can be strenuous given that they occur night in and night out, but the WWE isn't taking any chances with a performer who has suffered 10 documented concussions.

"The big concern with concussions is that, this has happened to me in the past, you don't know you had a concussion and your instinct as an athlete is to say, 'Hey, I'm fine,'" Bryan said in a recent interview with ESPN. "What we do now ensures that doesn't happen."

WWE put this very specific and sometimes tedious concussion protocol in place after Bryan was cleared for physical activity by an independent group of neurosurgeons, neurologists and concussion experts, as well as WWE medical director Joseph Maroon, in March 2018. These precautionary measures are well worth the hassle to WWE after Bryan was initially forced to retire in February 2016 due to a history of concussions and the discovery of a lesion in his brain.

Despite the logistical hurdles he has to face every time he steps out of the ring, Daniel Bryan couldn't be happier with the state of his life and his renewed WWE career. WWE

Ten months and nearly 100 matches after he made his return at WrestleMania 33, Bryan still has to go through each and every step of the protocol once he makes his way backstage. WWE hasn't deviated from the strict routine despite Bryan claiming he's feeling "really, really good" as he's yet to suffer any setbacks. Bryan is hopeful that all of those positive results will result in a turn back toward the baseline.

"It's still pretty much the same, but we're working on loosening it up a little bit because our doctors do have to look after other people, right?" Bryan said with his signature chuckle. "So it's like, I go out, I do a match and I'm fine and they're having to do all these tests with me, so we're working on loosening that up a little bit. But that's more of a thing as far as getting everything legally to where we could do that sort of thing."

Bryan on facing AJ Styles through the years "When AJ came here, I was really sad because that was when I wasn't cleared to wrestle," Bryan said. "It didn't look like WWE was gonna clear me to wrestle. I was like, 'Man, I've known AJ for years and we're never gonna get a chance to wrestle on the WWE stage.' You talk about the 2002 Ring of Honor show, at least at that show, there was like 300 people there; 300 people is not a lot of people in comparison to however many people there's gonna be at the Royal Rumble -- I don't know, like 30-40,000 -- but AJ and I also wrestled in 2005, [too]. It's on YouTube, and I feel like there's 40 people there [laughs]. "People may not understand the difference between 300 people and 40 people, but when you're wrestling in a high school gym, the difference is huge. 300 people is a crowd. 40 people is just a smattering of people. The whole thing is surreal. But to be fair, I feel like most my career has been surreal in general. We're gonna be wrestling at Chase Field in Phoenix which is really cool, because it's a baseball stadium and I think that's gonna be a lot of fun."

Part of the reason Bryan hasn't suffered any setbacks might be attributed to his lighter schedule. Bryan wrestled 227 matches during his last full year of pre-retirement WWE performances in 2013. This calendar year, he's on pace for around 120. Bryan's limited schedule allows him more time to recover in between matches -- and also gives him more time with his baby girl, Birdie.

"I think the schedule that I'm on now is pretty much the schedule that I'll stick to, if not even a little bit lighter as I get older," Bryan said. "I'm 37 now, I'll be 38 this year, and all this takes a toll on your body. I love wrestling, like love, love, love wrestling, and anyone who knows me knows I love wrestling -- but it's no longer the No. 1 love of my life. I want to be able to spend time with my family, I want to be able to take vacation, I want to be able to do some of those fun things. I envision it being this schedule or lighter, probably, from here on out."

His post-match process might be different, and his priorities may have shifted, but the change that fans have noticed most has happened on a weekly basis on SmackDown. Bryan -- whose relatable appearance, sympathetic plight and pop-culture-transcending "YES!" chants won him fans the world over -- has entered the new year as WWE's top heel. As with many of the most effective heel turns in the annals of WWE history, the moment was both shocking and believable.

The moment he snapped came in a WWE championship match against AJ Styles ahead of Survivor Series in November. Bryan low-blowed Styles before capturing the WWE championship for the first time since he had to relinquish the belt in May 2014. Many fans questioned why WWE would turn one of its popular babyface acts, but it's crucial to note that it was actually Bryan who asked for the sudden change of character.

The effectiveness of Daniel Bryan's on-screen presentation can largely be attributed to the fact that the words he's speaking are permutations on the way he actually feels about key issues. WWE

"It's interesting, because it's coming from this idea that when I came back, I really felt this pressure to be the Daniel Bryan that everybody used to know. I had moved on from that mentally," Bryan said. "When I was an active wrestler, my style evolved over time and one of the things I really enjoy about the craft of wrestling is that my character, my style, everything changes over time as I see what works and what doesn't work.

"When I came back, it was almost like my style and my character were stuck in 2014, which at this point is almost five years ago. I came back and I really felt that. I really want to change. There are these expectations that fans have of me, that the company has of me, that they want the video shots of everybody chanting, 'YES,' and I was sick of those expectations. Doing what I'm doing now allows me to wrestle and present myself in a way that excites me -- and that really keeps me mentally invested in what I'm doing."

What Bryan is doing now is some of the best heel work WWE has seen in years. The effectiveness of Bryan's on-screen persona stems from his character being far from an average, formulaic, lying, cheating heel. Bryan borrows from his viewpoints as a proud vegan and environmentalist for ammo against his opponents and the WWE Universe -- and to this point, it has been a tremendously potent well to draw from.

Bryan's experiences during his time out of the ring also inform the "new" Daniel Bryan. The "old" Daniel Bryan was never viewed as a skilled talker, but the "new" Daniel Bryan can do no wrong with a mic in his hand. Kicking off an episode of SmackDown in front of a hoard of WWE fans at a concession stand? Bryan put on a masterful performance as he compared fans abusing hotdogs, soda and the plastic they're served in to cheering for Styles.

Or how about when Bryan interrupted Cathy Kelly and Mike Rome's holiday segment on the TLC Kickoff show to rant about society's lack of deep thinking and how it leads to compulsively buying WWE merchandise? Bryan's anti-consumerism complaints even come down to the very detail of the leather strap of his WWE title, which he says "was made from a skinned cow that I like to name Daisy."

None of Bryan's promos picked up nearly as much attention as his most recent diatribe, though, as he stood face to face with his billionaire boss Vince McMahon Tuesday on SmackDown. Bryan ripped into McMahon and his baby boomer generation for "putting profits over both the people and the planet" and creating economic and environmental debts that fans happily ignore. These outbursts don't sound like traditional wrestling promos, and they're not meant to.

Daniel Bryan is in the midst of a fascinating rivalry with AJ Styles that has seen both men doing some of their best work in recent memory against one another. WWE

Bryan is channeling genuine beliefs, and for the first time, he's been given the freedom to voice them in front of an audience. For that reason, he's never been more confident on the mic.

"When you talk about the time off giving you a different perspective and being good for you, one of the things that it really did was they put me in the General Manager role where my only job was talking, so I had to get better at it," Bryan said. "When you're a good guy, people don't understand how hard it is to be a good guy and go out there and say things that get people to like you and to keep people liking you. For me, to say things that I really believe and that are actually true, that's not hard at all. When somebody asked [Brie Bella] about my character she goes, 'Ugh, that's just Bryan. That's just how he talks'. So maybe that's what makes it a lot easier."

Bryan certainly seems to be peaking at the right time, with the Royal Rumble set to take place at Chase Field in Arizona on Sunday, with Bryan playing a key role as he defends his WWE championship against longtime foe Styles. The 2019 Royal Rumble marks five years since the 2014 Rumble, when fans hijacked the match in frustration over Bryan not being involved. That infamous moment helped crystallize just how much fan support there was for Bryan. In his mind, their chants for Bryan, their boos for both Rey Mysterio and Batista, and CM Punk leaving WWE the next day were the converging forces that pushed Bryan into the main event of WrestleMania 30.

"I don't know if that was the most pivotal night in 2014, but it sure feels like it because that was the moment that it wasn't just, 'Oh, Daniel Bryan is getting a lot of cheers.' People were angry that Daniel Bryan was not being put in a position to succeed," Bryan said. "There's a difference between being cheered and people caring so much that they're angry that their guy isn't out there. I think that's when the perception of the company really started to shift as far as like, 'We knew he was popular, but we didn't think it was this.' That and CM Punk quitting the next day were the real game-changers as far as me ending up main-eventing WrestleMania 30."

After his match with Styles on Sunday, Bryan will run through the gamut of tests with which he's become all too familiar over the past year. He'll have to answer any complicated math equation thrown his way just moments after tearing it up inside the ring in front of tens of thousands of fans at Chase Field. And he's willing to do it a thousand more times if that's what it takes to continue to do what he loves.

"I've lived a very blessed life regardless of if I weren't cleared or if I was cleared," Bryan said. "Everything you get in this life, you have to keep in mind that I'm very, very blessed. I had that time where when I was off, my wife and I had a baby, I was able to mentally re-think how I thought about wrestling so that when I came back I was much more appreciative of what this is and what it means to my life. That doesn't mean if I had been wrestling all those years, I wouldn't have grown, I wouldn't have changed into a different version of Daniel Bryan.

"This is just how it ended up, but I'm grateful for how it ended up."