This Video Of Rory McIlroy Training Will Show You Golf Isn't Just A Leisurely Sport For Retirees

03/25/2015 03:19 pm ET | Updated Mar 25, 2015

The impression many people have of golf is that of a casual 18 holes on a Sunday morning, requiring little to no physical exertion. Or a sport mostly enjoyed by retirees or power executives with too much time on their hands.

So why then is Rory McIlroy working out so hard in this video?:

The video, posted Tuesday by Nike, is part of Nike Training's new "Inner Strength" documentary series, which explores different athletes and their process for getting in shape to dominate their respective sport.

“I had huge amounts of mobility and flexibility -- that's never been my problem, but I couldn't stand on one leg for more then 10 seconds. I couldn't hold a plank for more than 30 seconds,” McIlroy, currently ranked the world No. 1, said.

"I wasn't really big into the gym," he says of his regimen before pairing up with exercise physiologist Dr. Steve McGregor in 2010.

What started as a way to help his back, McIlroy says he now hopes training will extend his career by increasing both his muscle strength and stamina.

“If this can help me get an extra two or three years out of my career or help me get one shot a round … whether it’s because I’m more mentally focused, more fit or more confident,” he said. “I feel like getting in here gives me the best possible chance to go out on the golf course and perform to the best of my ability.”

And don't let the stationary bike fool you, because by the 0:42 second mark, the pro golfer, who will be taking part in the Master's Tournament in April, is lifting some serious weight:

And doing this:

And whatever this is:

But of course, at the end of the day, Rory just does what Rory does best:

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