BOSTON (CBS) — Jaylen Brown is a pretty physical specimen, a ridiculous athlete who seems to get more strapping by the day. And if you’re worried that he may lose some of his explosiveness during the NBA’s current hiatus, you shouldn’t be.

Brown may not be putting up some high-stake jumpers at the moment, but he’s going above and beyond to stay in shape. He’s doing so with the help of his 78-year-old grandfather, a former boxer who sparred against greats like Muhammad Ali, Joe Frazier and Sonny Liston.

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We’ve gotten a glimpse of Brown’s hefty workouts, but The Boston Globe’s Adam Himmelsbach offered an in-depth look at everything Brown is doing on Monday. It started with convincing his grandfather, Willie Brown, to leave Atlanta for Boston.

For Jaylen, it was more than just getting someone to help him stay in shape — or get in even better shape — while away from the basketball court. His Paw-paw lives alone, and he was concerned about him riding out the COVID-19 storm by himself. So he wanted to make him feel comfortable with his move up north.

Willie seems to be doing just fine living with and training his grandson.

“We said we needed him to help me train and get back ready for the season, so he could feel comfortable sticking around here,” Jaylen told The Globe. “But on the other side of that, he’s like, ‘OK, we’re going to train then.’ We’ve been training hard and a lot. On one hand, it’s great that he’s comfortable being here, but on the other he’s making me work my [butt] off.”

The senior Brown would wake Jaylen up at 7:30 each morning and put him to work, making his grandson jump rope and carry five-pound weights as he ran up and down the street, in addition to some boxing exercises and resistance-band training.

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Despite not playing in an NBA game for over two months, the 23-year-old Brown says he’s now in the best shape of his life.

“He has me doing a lot of things I’ve never done before,” said Jaylen. “It’s the old way of training. Everything he does is kind of a throwback, but it’s good. He’s never been stagnant, and I got that from him.”

The elder Brown is a former Marine who did a tour in Vietnam. He would have loved to have made a career out of boxing, but didn’t think he could make a living out of it. He became a truck driver, but offered to be a sparring partner for anyone training for a fight across the country. That’s when he did some dancing with greats like Ali and Frazier.

Now, he’s happy to pass along his knowledge — and those trick of the trade — to his grandson.

“It’s beautiful,” Willie told The Globe. “I can’t believe it myself. He works like a pro. It’s in his blood, you understand that? He does amazing things.”

Brown was having a breakout season in his fourth year in the NBA, averaging a career-high 20.4 points and 6.4 rebounds for Boston before the season was put on hold. He had taken his already explosive game to a whole new level, improving on nearly every front.

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While he may be off the court at the moment, it certainly sounds like he’ll pick up right where he left off when the NBA returns to action — with a few new tricks up his sleeve.