JAYSON TATUM'S NBA FINALS debut did not go as planned.

Not only did the Boston Celtics fall to the Golden State Warriors in six games last season, watching Stephen Curry and the Warriors claim a fourth championship in the past eight years on the floor at TD Garden, but Tatum saw massive drops in his offensive numbers as his playoff minutes piled up.

Tatum shot 36.7% overall in the six games -- 30.7% from 3-point range -- with nearly five turnovers per contest in Boston's four losses.

After failing to earn a ring, Boston's 23-year-old star forward decided during the offseason that some things were going to change.

He tweaked his diet. He ramped up his weightlifting routine. He devoted workouts to the rigors of postseason basketball. All of this to ensure Tatum wouldn't run out of gas at the end of 82 regular-season games and the two-plus months of high-level, high-intensity playoff contests.

"I was very durable last season, and throughout the course of my career," Tatum said during All-Star Weekend in Salt Lake City, where he captured All-Star Game MVP.

"But I feel like the changes we made this offseason, they prepared me to play heavy minutes, so it's not a shock when we get to the playoffs. It's just kind of a gradual build."

The result? Tatum has maintained his efficiency while playing the second-most minutes per game in the NBA: 37.3, just 0.2 behind Toronto Raptors All-Star Pascal Siakam.

And, as the Celtics (44-18) enter Wednesday's game against the Cleveland Cavaliers (7:30 p.m. ET, ESPN), they do so with Tatum playing at an MVP level, on pace to become the first Celtic to average at least 30 points per game over an entire season.

Tatum is also following in the footsteps of other stars -- from LeBron James to Kevin Durant to Giannis Antetokounmpo -- who, as their careers evolved, mastered how to manage their bodies to peak when it mattered most.

"[Tatum is] very detailed," Celtics coach Joe Mazzulla said. "He doesn't waste time. He's made a conscious decision and investment in his body as far as lifting, as far as sleep, as far as breathing, as far as his diet. So everything he does now is set up to where he can be at his absolute best. ...

"I think some of that just comes with time. Some of that just comes with learning how to do it."

TATUM'S FINALS STRUGGLES could be seen as a by-product of a grueling regular season and postseason. The truth, though, was that not only did Tatum play heavy minutes across the 2021-22 season, but that grind was coming on the heels of arguably the busiest stretch any NBA player has had over the past three years.

Tatum went from the Eastern Conference finals in the NBA's Orlando bubble in the summer and fall of 2020 right into starting the 2020-21 season in late December. He spent the summer of 2021 helping Team USA win gold at the Tokyo Olympics, then marched all the way until late June last season during a Finals run that featured back-to-back seven-game series against the Milwaukee Bucks and Miami Heat.

And since the start of the 2020 NBA playoffs, Tatum leads the NBA in games played (244) and minutes (9,045).

"His legs were gone," Drew Hanlen, Tatum's longtime trainer, told ESPN. "We tried to look at it from a perspective of 'What can we do to try to prevent that from happening?'"

Hanlen, Tatum and his personal strength coach, Nick Sang, devised a comprehensive offseason plan. First came Tatum's nutrition regimen. Rather than cutting out specific foods, it was designed instead to accomplish specific goals.

"Everything is just healthier options," Tatum said. "Not like a vegan or anything. But whether it's eggs, [eating] organic eggs, or the meat that I eat, and [the time and] what I'm eating after the games or what I'm eating pregame. Being just kind of punctual about things like that, and I've noticed the difference."

Added Hanlen: "Before, each year was like, 'Oh, I'm going to eat less bad and more good.' This is the first time where he [said], 'Here is my plan.'"

Tatum also fine-tuned his workouts, including diligent weightlifting sessions with Sang after games. The same went for his summer workouts with Hanlen, which not only focused on skill improvement -- finishing inside became a focus after seeing how physical things got during the 2022 playoffs -- but also faster-paced workouts designed to force Tatum to play through fatigue.

And if Tatum needed any pointers on how to maximize his level of play late in the season, he could look across the country at his rival in Los Angeles, as no player in league history has maintained themselves throughout their career better than James.

Now in his 20th NBA season, the league's all-time leading scorer has been the picture of consistency for a generation. Despite some nagging injuries in recent seasons, he still boasts averages of 29.5 points, 8.4 rebounds and 6.9 assists at 38 years old.

"My secret? Well, I tell you my secret, [but] it wouldn't be a secret anymore," James said during All-Star Weekend.

"But I would say just dedicating myself to the game. I've never cheated the game. There's a saying in sports called the 'game gods,' and when you cheat the game gods or you shortcut the game gods, karma comes with that, and they will figure out a way to get you back.

"I learned that at a very young age. I've never cheated the process of how great I can be or how I can maximize my potential."

PEER INTO ANY NBA locker room postgame and two types of players will emerge: The guy on his rookie deal, bouncing around with endless energy, and the veteran, loaded up with ice, trying to stay ready for the next game.

"You're just aware of the cooldown and how long it takes after the game," LA Clippers star Paul George said during All-Star Weekend. "Icing down, getting treatment ... when you're young, you don't think about it like that after a game -- straight to the showers, you're out of there.

"But as I've gotten older, putting the emphasis on after the game, make sure I'm doing my checklist of everything [to get] to the next day."

That checklist grows longer, especially for players such as Tatum, James or Antetokounmpo, who not only are expecting to play until late June every year, but also carry the burden of leading their teams there.

There might not be anyone who has a more difficult task from that standpoint than Antetokounmpo, who spends much of his on-court time using his singular combination of size and speed to inflict a pounding on his opponents -- one that, by extension, leads to a natural pounding on Antetokounmpo's own frame.

As he sat surrounded by reporters at All-Star Weekend, Antetokounmpo was nursing his own injury, a right wrist sprain suffered a couple days earlier when he hit it on the stanchion in a win against the Chicago Bulls.

Antetokounmpo tabbed James as an example of the expense -- from time to money to mental willpower -- that it takes to consistently stay ready to play at that level.

"I've heard a lot of times that LeBron spends a million dollars a year on his body," Antetokounmpo said. "You have to invest in your body. We are a company. Some players here make more money than the 500 best companies in the world. ...

"The best investment you can do is yourself. It's your body, so the more you invest in your body, the more it's going to last, the more you'll be able to perform everything at a high level."

TATUM'S MINUTES HAVE been a recurring topic around the Celtics this season. But Mazzulla, who consistently monitors Tatum's workload, said those conversations are focused on the wrong things.

"We're spending too much time talking about how many minutes he is playing instead of how he is embracing the responsibility of being a great player, and doesn't want to sit out games," Mazzulla said.

"Yes, he's made great adjustments as far as his mental approach, his diet, his exercise, his lifting ... investments in his life that have helped him take on this responsibility."

What's even more important, both to Tatum and the Celtics, is making that final leap forward in the playoffs. Essentially from the moment the Celtics lost to Golden State last spring, players up and down the roster -- led by Tatum and fellow All-Star Jaylen Brown -- have been vocal about not settling with one trip to the Finals.

Boston wants to get back there again. And the process of achieving that goal began last summer, shepherded by Tatum's drive to be ready for Game 102, not just Game 82.

It took last year's Finals disappointment for Tatum to realize what players such as Antetokounmpo and James have known for years. And he spent the summer trying to ensure things would go differently for this year's playoffs.

"We have the opportunity to do something special for a short amount of time, and you want to take and seize every opportunity you have," Celtics guard Marcus Smart told ESPN. "That just shows the growth and maturity and who [Tatum] is.

"When you come so close, it's not the big steps that are going to matter. It's the little steps, those little motions that you've got to work on that are going to put you over the top."