You've got to see Robert Durbin's transformation to believe it.

Durbin, a 64-year-old great grandfather from Louisville, Ky., was confined to a wheelchair for several years after he broke both of his ankles in a fall in 1987. He ballooned to 208 pounds.

About nine years ago Durbin started hitting the gym, and during the past decade he's become as ripped as they come. These photos of his transformation are unbelievable:

Durbin told the blog "Fitness, Food and Style" that adjusting his diet has been an important part of his bodybuilding routine.

"As a kid I ate country style every thing cooked in lard or bacon grease and same as my adulthood, I just ate more of it," Durbin said. "Since body building the hardest part of eating was smaller portions, now for me I have the perfect diet. "

In a new video, which has accumulated tens of thousands of views since it was posted Monday, Durbin shows off his incredible feats of strength.

These include one-handed push-ups and "the flag," the move in which you grab an upright pole and hold your body parallel to the ground. You can see him perform this at the 1:36 mark of the video.

Durbin says he feels better now than he did at 18.

And if that wasn't enough to convince you that Durbin is one of the fittest great-grandfathers in the world, check out these clips from his Instagram account:

If Durbin keeps up this routine for 30 years, maybe one day he'll be able to beat the marks set by 93-year-old bodybuilder Charles Eugster.

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