While training for his recent boxing match with Nate Diaz, a mixed martial artist, Jake Paul headed to a running track near his base in Dorado, P.R., alongside Larry Wade, his new strength and conditioning coach.

Wade planned to put Paul, the social media star turned pro boxer, through 2.5 miles of running. In the context of traditional road work, which involves long runs at a low but steady effort level, that distance seems insignificant.

But the workout Wade had planned was all about intensity.

He had Paul start with an 800-meter run, follow it with a 400 and then finish with a pair of 200s, each run separated by a one-minute rest. Following a short break, Paul repeated that sequence. After another quick breather came a 400 and two 200s.

For Wade, it is a benchmark workout for a modern boxer that indicates how much output they can muster during rounds, and how well they will recover between them.

The structure of that lung-busting workout also reflects Wade’s background. Before reinventing himself as a strength and conditioning coach for world-class boxers, Wade was best known as a top 110-meter hurdler, who won an N.C.A.A. title in 1998 and finished fourth at the 2003 world championships.

He went on to be an assistant coach at the University of Nevada, Las Vegas, where his wife, Yvonne Wade, was the head track and field coach until 2021. He still consults track athletes, but several breakout performances from a growing roster of clients have made Wade, 48, one of the most sought-after strength coaches in boxing. While track and field gave him his start as an athlete and a coach, Wade said, the aggressiveness with which he attacked his hurdle races translated well to his new sport.

“I was a boxer in tights. The mind-set fits,” Wade said in an interview. “It was the first time I truly felt comfortable in the element.”

Wade trains three world champions, including Robeisy Ramirez, the World Boxing Organization featherweight champion, as well as the super bantamweight Marlon Tapales and Rolando Romero, a super lightweight.

Athletes say they benefit from the emphasis on quality over volume in Wade’s training regimen. Paul said his session introduced him to sensations beyond pain and fatigue.

“During the 800, your body kind of goes into this shock mode,” Paul said in an interview before the Diaz fight, which he won by unanimous decision to improve to 7-1. “You start tingling. My whole back and body were tingling.”

Wade’s involvement in boxing happened by chance. In the summer of 2013, Wade was trackside at U.N.L.V. when he saw an athlete churning through a set of sprints. Wade thought the workout looked grueling, but lacked purpose. After the session, Wade approached the athlete, whom he had assumed was a football player, and offered to help.

The athlete was, in fact, Shawn Porter, the welterweight title contender. Porter invited Wade to volunteer at his next training camp. Wade optimized Porter’s running workouts while learning the nuances of boxing from Porter, who won two world titles while training with Wade.

“He helped me focus not so much on just making it through runs, but doing them with integrity,” said Porter, who retired from boxing in 2021. “He’s big on managing your energy. If fighters are paying attention, that’s what they’ll realize he’s giving you on fight night. A way to manage your energy.”

Superficially, hurdling and boxing have little in common. Hurdlers each run in their own lanes, and collide only by accident. In boxing, contact is the point. And while a world class men’s 110-meter hurdle race ends in roughly 13 seconds — Wade’s personal best was 13.01 seconds — boxing matches can last 36 minutes.

But Wade points out that preparing an athlete for either sport requires a detailed knowledge of the body’s energy systems and how they interact and interfere with each other. Long, steady runs, for example, improve baseline aerobic fitness, Wade said, but they do not prepare a fighter for the flurries of intensity that define high-level boxing.

So Wade takes his fighters to the track, where they might perform quarter- and half-mile runs, or run for 90 seconds, and then hit target mitts for 90 more.

“All that long-run stuff has nothing to do with short bursts and explosions,” Wade said. “You can run miles all day. It doesn’t mean you can throw combinations all day.”

Paul weighed in at 185 pounds for his match with Diaz, and appeared both leaner and more muscular than in February, when he lost a decision to Tommy Fury, the first, and only, full-time boxer he had faced. The changes were not just cosmetic.

“More weight, more push-ups, more pull-ups than I’ve ever done,” Paul said of his new strength.

Wade is one of several high-level boxing strength coaches with track and field backgrounds. Joey Scott, who trains the former heavyweight champion Deontay Wilder, also runs a track club in Miami. The lightweight champion Gervonta Davis does strength and conditioning work with Mo Wells, a former track athlete who also coaches Alaysha Johnson, the sixth-fastest 100-meter hurdler this season.

All three coaches are part of a broader trend toward more modern conditioning regimens for world-class boxers. Terence Crawford ran and swam to prepare for his dominating win over Errol Spence Jr. last month, but he also lifted heavy weights.

Wade traces this shift away from old-school conditioning programs to his mentor, Mackie Shilstone, who is best known for helping guide Michael Spinks to his upset win over the heavyweight champion Larry Holmes in 1985. Shilstone’s program favored track work over distance runs and weight training over calisthenics, and it paid close attention to nutrition.

Spinks bulked up from the light heavyweight class to heavyweight without losing speed, and defeated Holmes over 15 grueling rounds.

Still, some traditionalists weren’t convinced.

“Nutrition sucks. Wind sprints suck too,” the famed trainer Angelo Dundee, who died in 2012, told Sports Illustrated in response to Spinks’s win in 1985. “And if I catch a fighter of mine near a weight room, he better be able to take a baseball bat to the head.”

While Wade said today’s boxing trainers are more enlightened, he still encounters resistance from new clients who cling to old habits.

“I knew I brought something different to the table,” Wade says.

If a boxer insists on 10-mile training runs, Wade will first try to dissuade them. Otherwise, he will compromise at five miles.

And he will ask them to commit to the process and note the results.

When Ramirez first hired Wade, the boxer, who competes at 126 pounds, could perform only 35 push-ups in one set. Ramirez now can do many more than that and bench presses 235 pounds, which indicates a significant jump in strength.

Last month, Ramirez stopped Satoshi Shimizu with a series of power punches to defend his W.B.O. title. The outcome, Wade said, points to the real purpose of those track and weight room sessions.

“It becomes less about how much can this guy lift heavy than how much can he utilize,” Wade said. “That’s the real key.”