Tim Duncan hasn’t returned to the gym yet. But shortly after his season ended, and about three or four times a week since, he’s driven to Alamo Heights to train in martial arts.

What began as taekwondo and evolved to muay thai, has now turned into Dutch kickboxing. And as Duncan sweats, as determined as ever to learn the next nuanced maneuver, not only is his return to the Spurs more likely.

So is a healthy return.

Maybe his late-career success can be attributed to genetics or luck or both. When Kyrie Irving became the latest NBA player to fall, after all, there was no way to know what could have prevented a broken kneecap.

Still, Irving’s injury fits with a league-wide epidemic. And back in December, after seven of the top 11 draft picks had suffered a physical setback, a trainer shared his theory.

Tim Grover, best known for once calling Michael Jordan a client, wrote in Sports Illustrated:

“Hundreds of games, thousands of hours, since they were old enough to pick up a ball. … No time for rest or recovery. No time to play or train for other sports. End result: The same muscles, ligaments, tendons, and joints are used over and over again, in the same direction, the same angles, the same motions. What piece of machinery doesn’t eventually give out from repeated use over many years? At some point, the human body just says, ‘Enough.’”

Duncan’s body seemed to be saying that around 2010. Given the status of his left knee, surgically repaired in the summer of 2000, his decline seemed to come at an appropriate time.

Duncan reacted by changing his diet, and he continued to go to the Spurs’ practice facility to work on his game. But just as his athletic career began in swimming, he continued to search for ways to vary his activity. When he hasn’t been lifting tractor tires, he’s been boxing.

James Leija has monitored the latter. He will again starting next month, and he thinks it is this dedication that saves Duncan.

Leija says Duncan is like Floyd Mayweather in that he never stops training. “Most guys get hurt because they are out of shape and trying to get it back,” Leija said Saturday. “Tim never gets out of shape.”

Leija knows firsthand how far Duncan takes this. Sometimes, in the middle of July, Duncan will want to go outside at midday to hit the mitts with him.

“If I had more like him in boxing,” Leija laughed, “I would have a few world championships.”

Duncan has been most consistent, however, with martial arts. He works with a local trainer named Jason Echols, and what Duncan contributed for Echols’ website addresses Grover’s theory.

“I’ve used many different forms of off-season conditioning throughout my career,” Duncan wrote, “but have found my training with Jason to be the longest lasting because of its ever-changing and challenging workouts.”

Echols doesn’t pretend to have all the answers. But he’s always been an advocate of this kind of training because, as he put it, “it grounds an athlete.”

He loves the cross-training potential. “It increases your hand-eye coordination, literally connecting your brain to your body,” Echols said Saturday. “And when you put it in the hands of someone like Tim Duncan, it can turn into magic.”

Echols says Duncan works on this as he does his jumper. He pays attention to detail, from the footwork to the transfer in weight.

“He eats it up,” Echols said.

And when asked what others ask him, that all of this suggests Duncan must be preparing to return for another season, Echols is smart enough to protect his client.

“I don’t know if even he knows that,” Echols said.

So for now Duncan will train at martial arts, as he’s done for the past half-dozen years. And while it might be nothing more than a great way for a 39-year-old to stay in shape, the byproduct of what he is doing is undeniable.

Something else Duncan put on Echols’ website speaks to that. “It’s been a great way,” Duncan wrote, “to get my body ready for the rigors of my season.”

bharvey@express-news.net

Twitter: @Buck_SA