LeBron James remains one of the NBA’s top players at 39, with his incredible longevity standing as perhaps his greatest accomplishment. This endurance can be traced back to one key trait instilled by his longtime trainer, Mike Mancias, since LeBron was a teenager.

During an appearance on the High Performance podcast, host Jake Humphrey asked Mancias what the most valuable lesson he had imparted to LeBron over their 20-year relationship. Mancias responded that he had emphasized the importance of consistency, a principle LeBron embraced and made a part of his daily life.

“The most important thing I could have taught him is just to stay consistent,” Mancias said. “We push each other every day. I really believe we’ve taught each other how to develop extreme consistency.”

Mancias went on to highlight how consistency is crucial in team sports, explaining that a player like LeBron, with his relentless drive, sets an example for teammates. “When you’re consistent in your behavior, attitude, and performance, your teammates know they can rely on you without question,” the trainer added.

LeBron credits much of his remarkable achievement—playing at an All-NBA level for two decades—to Mancias’ guidance. As the 20th NBA season of his career wound down, LeBron acknowledged Mancias’ impact during an interview in April 2023.

“Without him, I wouldn’t have made it through 20 seasons,” LeBron admitted. “It’s that simple. I couldn’t continue to play at this level without him. He’s that vital to my performance, my game, and even my mindset. Seven, maybe twelve years might’ve been possible, but twenty? No way without him.”

Mancias has been by LeBron’s side throughout his NBA journey, which shows no signs of slowing down. LeBron’s impressive showing at the 2024 Paris Olympics further demonstrated his enduring hunger to compete at the highest level, even after two decades. As LeBron prepares for his 22nd NBA season, Mancias will continue pushing him just as hard as he did when they first started working together.