Time off didn’t interest Romeo Okwara. Neither did strictly football-related training. The second-year defensive end got a taste of NFL success his rookie year and didn’t want it to be fleeting.

So the open-minded Okwara, a photographer in his spare time who also can play three instruments, thought outside the box. He spent his downtime in Las Vegas training with a former Navy SEAL.

“I’m always open to try to experience new things,” Okwara said Friday after Giants practice.

Especially if it can translate to success on the football field. The Nigerian-born Okwara, 22, spent six weeks with Steve Chayra of Red Road Training in the spring and another month in the summer. They were introduced through a mutual friend and hit it off. Chayra promised the training would be applicable to football, and Okwara was all in.

“He’s one of those stories I really gravitate towards,” Chayra said in a phone interview, referring to Okwara going undrafted out of Notre Dame yet beating the odds to earn a roster spot with the Giants last summer. “I saw this huge kid, real humble good kid. I though there were some things I can pass on via my background.”

They met four days a week, spending one of those days in the pool. That’s where the real challenges took place. Okwara, training alongside Minnesota Wild hockey player Jason Zucker, ran with weights underwater and swam 25-to-50 meters underwater while holding his breath. They practiced tumbling to improve flexibility, and used different breathing exercises. Chayra wanted him to use his mind to control his body, as a way of mastering his focus, to get to be comfortable with being uncomfortable.

“I went in from the theory of strengthening the mind and the body will follow,” Chayra said. “He adapted so well to it. “In the third quarter, when other guys are tired, he can push through that.”

The purpose was to build endurance in a different setting, for the lineman to learn how to control his breathing when his muscles grow tired.

“Its more of a mental training, being able to push yourself when you’re tried,” Okwara said. “It was definitely challenging, but you get used to it, and you get better every day.”

Chayra praised Okwara’s willingness to try something new. He said Okwara never hesitated, taking the attitude of “What’s next?”

Okwara, meanwhile, said he has seen differences since the training: he feels faster and stronger, and is able to catch his breath quicker between plays.

Nevertheless, that doesn’t mean he thinks he could have been a Navy SEAL simply because he has undergone a tiny percentage of the training.

“It’s probably the toughest training you could have in the world,” Okwara said.

Okwara is hoping his extra training pays off. He’s coming off a strong rookie year, when he performed well in spot duty, after earning a roster spot with a stellar preseason that included a sack of Patriots superstar Tom Brady. He received five starts after Jason Pierre-Paul was lost to core-muscle surgery, making the most of it by producing a sack, 25 tackles and two passes defensed.

Though he doesn’t have to worry about his standing on the roster this year, his goal is to prove to coaches they can lessen the workload on stalwart defensive ends Olivier Vernon and Pierre-Paul by taking more reps.

“You want to be the guy to go in there and step up and perform the same way,” Okwara said. “You got to take advantage of every opportunity you’re given.”

He jumped at an opportunity in the offseason to improve himself, and it may lead to more chances on the field, too.